[v2,2/4] iio: adc: Add driver for Renesas RZ/G2L A/D converter

Commit Message

Prabhakar July 19, 2021, 8:58 a.m. UTC

Add ADC driver support for Renesas RZ/G2L A/D converter in SW
trigger mode.

A/D Converter block is a successive approximation analog-to-digital
converter with a 12-bit accuracy and supports a maximum of 8 input
channels.

Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Biju Das <[e-mail]>
---
 MAINTAINERS                 |   8 +
 drivers/iio/adc/Kconfig     |  10 +
 drivers/iio/adc/Makefile    |   1 +
 drivers/iio/adc/rzg2l_adc.c | 545 ++++++++++++++++++++++++++++++++++++
 4 files changed, 564 insertions(+)
 create mode 100644 drivers/iio/adc/rzg2l_adc.c

Comments

Jonathan Cameron July 24, 2021, 6:06 p.m. UTC | #1

On Mon, 19 Jul 2021 09:58:38 +0100
Lad Prabhakar <[e-mail]> wrote:

> Add ADC driver support for Renesas RZ/G2L A/D converter in SW
> trigger mode.
> 
> A/D Converter block is a successive approximation analog-to-digital
> converter with a 12-bit accuracy and supports a maximum of 8 input
> channels.
> 
> Signed-off-by: Lad Prabhakar <[e-mail]>
> Reviewed-by: Biju Das <[e-mail]>

Hi Lad,

A few additional comments inline.

Thanks,

Jonathan

> ---
>  MAINTAINERS                 |   8 +
>  drivers/iio/adc/Kconfig     |  10 +
>  drivers/iio/adc/Makefile    |   1 +
>  drivers/iio/adc/rzg2l_adc.c | 545 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 564 insertions(+)
>  create mode 100644 drivers/iio/adc/rzg2l_adc.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6c8be735cc91..6a52f9f4604c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15839,6 +15839,14 @@ L:	[e-mail]
>  S:	Maintained
>  F:	drivers/phy/renesas/phy-rcar-gen3-usb*.c
>  
> +RENESAS RZ/G2L A/D DRIVER
> +M:	Lad Prabhakar <[e-mail]>
> +L:	[e-mail]
> +L:	[e-mail]
> +S:	Supported
> +F:	Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
> +F:	drivers/iio/adc/rzg2l_adc.c
> +
>  RESET CONTROLLER FRAMEWORK
>  M:	Philipp Zabel <[e-mail]>
>  S:	Maintained
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index db0c8fb60515..af168e1c9fdb 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -887,6 +887,16 @@ config ROCKCHIP_SARADC
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called rockchip_saradc.
>  
> +config RZG2L_ADC
> +	tristate "Renesas RZ/G2L ADC driver"
> +	depends on ARCH_R9A07G044 || COMPILE_TEST
> +	help
> +	  Say yes here to build support for the ADC found in Renesas
> +	  RZ/G2L family.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called rzg2l_adc.
> +
>  config SC27XX_ADC
>  	tristate "Spreadtrum SC27xx series PMICs ADC"
>  	depends on MFD_SC27XX_PMIC || COMPILE_TEST
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index f70d877c555a..d68550f493e3 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -82,6 +82,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
>  obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
>  obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
>  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
> +obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
>  obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
>  obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
>  obj-$(CONFIG_STX104) += stx104.o
> diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
> new file mode 100644
> index 000000000000..033cdec9e976
> --- /dev/null
> +++ b/drivers/iio/adc/rzg2l_adc.c
> @@ -0,0 +1,545 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * RZ/G2L A/D Converter driver
> + *
> + *  Copyright (c) 2021 Renesas Electronics Europe GmbH
> + *
> + * Author: Lad Prabhakar <[e-mail]>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>

Add mod_devicetable.h and drop the of specific headers
as nothing in them used directly as far as I can tell.

> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +
> +#define DRIVER_NAME		"rzg2l-adc"
> +
> +#define RZG2L_ADM(n)			((n) * 0x4)
> +#define RZG2L_ADM0_ADCE			BIT(0)
> +#define RZG2L_ADM0_ADBSY		BIT(1)
> +#define RZG2L_ADM0_PWDWNB		BIT(2)
> +#define RZG2L_ADM0_SRESB		BIT(15)
> +#define RZG2L_ADM1_TRG			BIT(0)
> +#define RZG2L_ADM1_MS			BIT(2)
> +#define RZG2L_ADM1_BS			BIT(4)
> +#define RZG2L_ADM1_EGA_CLEAR		~GENMASK(13, 12)
> +#define RZG2L_ADM2_CHSEL_CLEAR		~GENMASK(7, 0)

I'd rather see these defined as _MASK and the
inversion made explicit inline.

> +#define RZG2L_ADM3_ADSMP		0x578
> +#define RZG2L_ADM3_ADCMP		(0xe << 16)
> +#define RZG2L_ADM3_ADIL_CLEAR		~GENMASK(31, 24)
> +
> +#define RZG2L_ADINT			0x20
> +#define RZG2L_ADINT_CH_CLEAR		~GENMASK(7, 0)
> +#define RZG2L_ADINT_CSEEN		BIT(16)
> +#define RZG2L_ADINT_INTS		BIT(31)
> +#define RZG2L_ADSTS			0x24
> +#define RZG2L_ADINT_INTST_MASK		GENMASK(7, 0)
> +#define RZG2L_ADSTS_CSEST		BIT(16)
> +#define RZG2L_ADIVC			0x28
> +#define RZG2L_ADIVC_DIVADC_CLEAR	~GENMASK(8, 0)
> +#define RZG2L_ADIVC_DIVADC_4		0x4

Perhaps adopt the _MASK and FIELD_PREP() approach to setting
particular values.  That way it is obvious at the call site that
DVADC_4 is a value within the DIVADC_MASK covered field.

> +#define RZG2L_ADFIL			0x2c
> +#define RZG2L_ADCR(n)			(0x30 + ((n) * 0x4))
> +#define RZG2L_ADCR_AD_MASK		GENMASK(11, 0)
> +
> +#define RZG2L_ADC_MAX_CHANNELS		8
> +#define RZG2L_ADC_CHN_MASK		0x7
> +#define RZG2L_ADC_TIMEOUT		usecs_to_jiffies(1 * 4)
> +
> +struct rzg2l_adc_data {
> +	const struct iio_chan_spec *channels;
> +	u8 num_channels;
> +};
> +
> +struct rzg2l_adc {
> +	void __iomem *base;
> +	struct clk *pclk;
> +	struct clk *adclk;
> +	struct reset_control *presetn;
> +	struct reset_control *adrstn;
> +	struct completion completion;
> +	const struct rzg2l_adc_data *data;
> +	u16 last_val[RZG2L_ADC_MAX_CHANNELS];
> +};
> +
> +static const char * const rzg2l_adc_channel_name[] = {
> +	"adc0",
Is it useful to expose these as labels to userspace?
Seems unnecessary given they map directly to the channel
numbers.

> +	"adc1",
> +	"adc2",
> +	"adc3",
> +	"adc4",
> +	"adc5",
> +	"adc6",
> +	"adc7",
> +};
> +
> +static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
> +{
> +	return readl(adc->base + reg);
> +}
> +
> +static void rzg2l_adc_writel(struct rzg2l_adc *adc, unsigned int reg, u32 val)
> +{
> +	writel(val, adc->base + reg);
> +}
> +
> +static void rzg2l_adc_pwr(struct rzg2l_adc *adc, bool on)
> +{
> +	u32 reg;
> +
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> +	if (on)
> +		reg |= RZG2L_ADM0_PWDWNB;
> +	else
> +		reg &= ~RZG2L_ADM0_PWDWNB;
> +	rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
> +	udelay(2);
> +}
> +
> +static void rzg2l_adc_start_stop(struct rzg2l_adc *adc, bool start)
> +{
> +	int timeout = 5;
> +	u32 reg;
> +
> +	/* stop A/D conversion */
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> +	if (start)
> +		reg |= RZG2L_ADM0_ADCE;
> +	else
> +		reg &= ~RZG2L_ADM0_ADCE;
> +	rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
> +
> +	if (start)
> +		return;
> +
> +	do {
> +		usleep_range(100, 200);
> +		reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> +		timeout--;
> +		if (!timeout) {
> +			pr_err("%s stopping ADC timed out\n", __func__);
> +			break;
> +		}
> +	} while (((reg & RZG2L_ADM0_ADBSY) || (reg & RZG2L_ADM0_ADCE)));
> +}
> +
> +static void rzg2l_set_trigger(struct rzg2l_adc *adc)
> +{
> +	u32 reg;
> +
> +	/* SW trigger */
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(1));
> +	reg &= RZG2L_ADM1_EGA_CLEAR;
> +	reg &= ~RZG2L_ADM1_BS;
> +	reg |= RZG2L_ADM1_MS;
> +	reg &= ~RZG2L_ADM1_TRG;
> +	rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
> +}
> +
> +static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
> +{
> +	u32 reg;
> +
> +	if (rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_ADBSY)
> +		return -EBUSY;
> +
> +	rzg2l_set_trigger(adc);
> +
> +	/* select channel */
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(2));
> +	reg &= RZG2L_ADM2_CHSEL_CLEAR;
> +	reg |= BIT(ch);
> +	rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
> +
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
> +	reg &= RZG2L_ADM3_ADIL_CLEAR;
> +	reg |= RZG2L_ADM3_ADCMP;
> +	reg |= RZG2L_ADM3_ADSMP;

No loss in readability in combining the two lines above and shorter
code is always good.  Having the mask on a separate line makes
sense but the |= pair doesn't.

What is a bit unusual here is you clear some bits then write different
ones.  That is presumably relying on the fact that the ADCCMP part
is always set to the same value.  That seems unwise to assume from
a long term maintainability point of view.

> +	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
> +
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADIVC);
> +	reg &= RZG2L_ADIVC_DIVADC_CLEAR;
> +	reg |= RZG2L_ADIVC_DIVADC_4;
> +	rzg2l_adc_writel(adc, RZG2L_ADIVC, reg);
> +
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADINT);
> +	reg &= ~RZG2L_ADINT_INTS;
> +	reg &= RZG2L_ADINT_CH_CLEAR;
> +	reg |= RZG2L_ADINT_CSEEN;
> +	reg |= BIT(ch);
> +	rzg2l_adc_writel(adc, RZG2L_ADINT, reg);
> +
> +	return 0;
> +}
> +
> +static int rzg2l_adc_set_power(struct iio_dev *indio_dev, bool on)
> +{
> +	struct device *dev = indio_dev->dev.parent;
> +
> +	if (on)
> +		return pm_runtime_resume_and_get(dev);
> +
> +	return pm_runtime_put_sync(dev);
> +}
> +
> +static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc, u8 ch)
> +{
> +	int ret;
> +
> +	ret = rzg2l_adc_set_power(indio_dev, true);
> +	if (ret)
> +		return ret;
> +
> +	ret = rzg2l_adc_conversion_setup(adc, ch);
> +	if (ret) {
> +		rzg2l_adc_set_power(indio_dev, false);
> +		return ret;
> +	}
> +
> +	reinit_completion(&adc->completion);
> +
> +	rzg2l_adc_start_stop(adc, true);
> +
> +	if (!wait_for_completion_timeout(&adc->completion, RZG2L_ADC_TIMEOUT)) {
> +		rzg2l_adc_writel(adc, RZG2L_ADINT,
> +				 rzg2l_adc_readl(adc, RZG2L_ADINT) & RZG2L_ADINT_CH_CLEAR);
> +		rzg2l_adc_start_stop(adc, false);
> +		rzg2l_adc_set_power(indio_dev, false);
> +		return -ETIMEDOUT;
> +	}
> +
> +	return rzg2l_adc_set_power(indio_dev, false);
> +}
> +
> +static int rzg2l_adc_read_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int *val, int *val2, long mask)
> +{
> +	struct rzg2l_adc *adc = iio_priv(indio_dev);
> +	int ret;
> +	u8 ch;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (chan->type != IIO_VOLTAGE)
> +			return -EINVAL;
> +
> +		ret = iio_device_claim_direct_mode(indio_dev);
> +		if (ret)
> +			return ret;
> +
> +		ch = chan->channel & RZG2L_ADC_CHN_MASK;
> +		ret = rzg2l_adc_conversion(indio_dev, adc, ch);
> +		if (ret) {
> +			iio_device_release_direct_mode(indio_dev);
> +			return ret;
> +		}
> +		*val = adc->last_val[ch];
> +		iio_device_release_direct_mode(indio_dev);
> +
> +		return IIO_VAL_INT;
> +
> +	default:
> +		return -EINVAL;
> +	}
> +}
> +
> +static int rzg2l_adc_read_label(struct iio_dev *iio_dev,
> +				const struct iio_chan_spec *chan,
> +				char *label)
> +{
> +	if (chan->channel >= RZG2L_ADC_MAX_CHANNELS)
> +		return -EINVAL;
> +
> +	return snprintf(label, PAGE_SIZE, "%s\n", rzg2l_adc_channel_name[chan->channel]);

sysfs_emit()?.

> +}
> +
> +static const struct iio_info rzg2l_adc_iio_info = {
> +	.read_raw = rzg2l_adc_read_raw,
> +	.read_label = rzg2l_adc_read_label,
> +};
> +
> +static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
> +{
> +	struct rzg2l_adc *adc = (struct rzg2l_adc *)dev_id;
> +	u8 intst;
> +	u32 reg;
> +	u8 i;
> +
> +	reg = rzg2l_adc_readl(adc, RZG2L_ADSTS);
> +	if (reg & RZG2L_ADSTS_CSEST) {

Probably good to add a brief comment on what is going on in this check.
Perhaps even an error print if it's an error path.

> +		rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
> +		return IRQ_HANDLED;
> +	}
> +
> +	intst = reg & RZG2L_ADINT_INTST_MASK;
> +	if (!intst)

I'm guessing this means spurious interrupt in which case IRQ_NONE
so the core irq code knows about it.

> +		return IRQ_HANDLED;
> +
> +	for (i = 0; i < RZG2L_ADC_MAX_CHANNELS; i++) {
> +		if (intst & BIT(i))

for_each_bit_set() and make intst a long so the types are right for
that macro


> +			adc->last_val[i] = rzg2l_adc_readl(adc, RZG2L_ADCR(i)) & RZG2L_ADCR_AD_MASK;
> +	}
> +
> +	rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
> +
> +	complete(&adc->completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int rzg2l_adc_parse_of(struct platform_device *pdev, struct rzg2l_adc *adc)
> +{
> +	struct iio_chan_spec *chan_array;
> +	struct fwnode_handle *fwnode;
> +	struct rzg2l_adc_data *data;
> +	unsigned int channel;
> +	int num_channels;
> +	int ret;
> +	u8 i;
> +
> +	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	num_channels = device_get_child_node_count(&pdev->dev);
> +	if (!num_channels) {
> +		dev_err(&pdev->dev, "no channel children\n");
> +		return -ENODEV;
> +	}
> +
> +	if (num_channels > RZG2L_ADC_MAX_CHANNELS) {
> +		dev_err(&pdev->dev, "num of channel children out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
> +				  GFP_KERNEL);
> +	if (!chan_array)
> +		return -ENOMEM;
> +
> +	i = 0;
> +	device_for_each_child_node(&pdev->dev, fwnode) {
> +		ret = fwnode_property_read_u32(fwnode, "reg", &channel);
> +		if (ret)
> +			return ret;
> +
> +		if (channel >= RZG2L_ADC_MAX_CHANNELS)
> +			return -EINVAL;
> +
> +		chan_array[i].type = IIO_VOLTAGE;
> +		chan_array[i].indexed = 1;
> +		chan_array[i].channel = channel;
> +		chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> +		chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
> +		i++;
> +	}
> +
> +	data->num_channels = num_channels;
> +	data->channels = chan_array;
> +	adc->data = data;
> +
> +	return 0;
> +}
> +
> +static int rzg2l_adc_sw_reset(struct rzg2l_adc *adc)
> +{
> +	int timeout = 5;
> +	u32 val;
> +
> +	val = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> +	val |= RZG2L_ADM0_SRESB;
> +	rzg2l_adc_writel(adc, RZG2L_ADM(0), val);
> +
> +	while (!(rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_SRESB)) {
> +		if (!timeout)
> +			return -EBUSY;
> +		timeout--;
> +		usleep_range(100, 200);
> +	}
> +
> +	return 0;
> +}
> +
> +static int rzg2l_adc_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct iio_dev *indio_dev;
> +	struct rzg2l_adc *adc;
> +	int ret;
> +	int irq;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	adc = iio_priv(indio_dev);
> +
> +	ret = rzg2l_adc_parse_of(pdev, adc);

*_parse_properties() or *_parse_firmware()
as it's not of specific now.

> +	if (ret)
> +		return ret;
> +
> +	adc->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(adc->base))
> +		return PTR_ERR(adc->base);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(dev, "no irq resource\n");
> +		return irq;
> +	}
> +
> +	adc->pclk = devm_clk_get(dev, "pclk");
> +	if (IS_ERR(adc->pclk)) {
> +		dev_err(dev, "Failed to get pclk");
> +		return PTR_ERR(adc->pclk);
> +	}
> +
> +	adc->adclk = devm_clk_get(dev, "adclk");
> +	if (IS_ERR(adc->adclk)) {
> +		dev_err(dev, "Failed to get adclk");
> +		return PTR_ERR(adc->adclk);
> +	}
> +
> +	adc->adrstn = devm_reset_control_get_exclusive(dev, "adrst-n");
> +	if (IS_ERR(adc->adrstn)) {
> +		dev_err(dev, "failed to get adrstn\n");
> +		return PTR_ERR(adc->adrstn);
> +	}
> +
> +	adc->presetn = devm_reset_control_get_exclusive(dev, "presetn");
> +	if (IS_ERR(adc->presetn)) {
> +		dev_err(dev, "failed to get presetn\n");
> +		return PTR_ERR(adc->presetn);
> +	}
> +
> +	ret = reset_control_deassert(adc->adrstn);
> +	if (ret)
> +		return ret;

devm_add_action_or_reset() here to make the reasserting of these part
of the automated cleanup.

> +
> +	ret = reset_control_deassert(adc->presetn);
> +	if (ret)
> +		goto assert_adrstn;
> +
> +	ret = clk_prepare_enable(adc->pclk);
> +	if (ret)
> +		goto assert_presetn;
> +
> +	ret = rzg2l_adc_sw_reset(adc);
> +	if (ret)
> +		goto unprepare_pclk;
> +
> +	clk_disable_unprepare(adc->pclk);

As below, reorder as:

	ret = rzg2l_adc_sw_reset(adc);
	clk_disable_unprepare(adc->pclk);
	if (ret)
		goto assert_preset_n;

> +
> +	init_completion(&adc->completion);
> +
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	ret = devm_request_irq(dev, irq, rzg2l_adc_isr,
> +			       0, dev_name(dev), adc);

Another aspect of the comment below about mixing and matching between
devm and not.  If the order of remove is not that opposite of probe
then there should be a comment saying why.  There are far too many
race conditions introduced by people doing things in a different order
without carefully considering why.

> +	if (ret < 0)
> +		goto assert_presetn;
> +
> +	indio_dev->name = DRIVER_NAME;
> +	indio_dev->info = &rzg2l_adc_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = adc->data->channels;
> +	indio_dev->num_channels = adc->data->num_channels;
> +
> +	pm_runtime_enable(dev);
> +
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		goto err_iio_device_register;
> +
> +	return 0;
> +
> +unprepare_pclk:
> +	clk_disable_unprepare(adc->pclk);

Bad sign that you have this here and not in remove..
When you have cases like this, it's normally better to
either factor out the relevant code into a function
that lets you do this call whether or not there is an
error, or to just move this up to the relevant if statements.


> +err_iio_device_register:
> +	pm_runtime_disable(dev);
> +assert_presetn:
> +	reset_control_assert(adc->presetn);
> +assert_adrstn:
> +	reset_control_assert(adc->adrstn);
> +	return ret;
> +}
> +
> +static int rzg2l_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct rzg2l_adc *adc = iio_priv(indio_dev);
> +
> +	reset_control_assert(adc->presetn);
> +	reset_control_assert(adc->adrstn);
> +	pm_runtime_disable(indio_dev->dev.parent);

You can't mix and match devm managed and unmanaged like this.
The userspace interfce is still exposed after you've put the
device into reset which is unlikely to be a good idea.

One option is to use devm_add_action_or_reset() to make
this stuff happen in the managed flow, which happens after
remove is done.  That would let you drop remove() entirely.


> +
> +	return 0;
> +}
> +
> +static const struct of_device_id rzg2l_adc_match[] = {
> +	{ .compatible = "renesas,rzg2l-adc",},
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, rzg2l_adc_match);
> +
> +static int __maybe_unused rzg2l_adc_pm_runtime_suspend(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct rzg2l_adc *adc = iio_priv(indio_dev);
> +
> +	rzg2l_adc_pwr(adc, false);
> +	clk_disable_unprepare(adc->adclk);
> +	clk_disable_unprepare(adc->pclk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused rzg2l_adc_pm_runtime_resume(struct device *dev)
> +{
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct rzg2l_adc *adc = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(adc->pclk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(adc->adclk);
> +	if (ret)
> +		return ret;
> +
> +	rzg2l_adc_pwr(adc, true);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops rzg2l_adc_pm_ops = {
> +	SET_RUNTIME_PM_OPS(rzg2l_adc_pm_runtime_suspend,
> +			   rzg2l_adc_pm_runtime_resume,
> +			   NULL)
> +};
> +
> +static struct platform_driver rzg2l_adc_driver = {
> +	.probe		= rzg2l_adc_probe,
> +	.remove		= rzg2l_adc_remove,
> +	.driver		= {
> +		.name		= DRIVER_NAME,
> +		.of_match_table = rzg2l_adc_match,
> +		.pm		= &rzg2l_adc_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(rzg2l_adc_driver);
> +
> +MODULE_AUTHOR("Lad Prabhakar <[e-mail]>");
> +MODULE_DESCRIPTION("Renesas RZ/G2L ADC driver");
> +MODULE_LICENSE("GPL v2");

Lad, Prabhakar July 25, 2021, 12:18 p.m. UTC | #2

Hi Jonathan,

Thank you for the review.

On Sat, Jul 24, 2021 at 7:03 PM Jonathan Cameron <[e-mail]> wrote:
>
> On Mon, 19 Jul 2021 09:58:38 +0100
> Lad Prabhakar <[e-mail]> wrote:
>
> > Add ADC driver support for Renesas RZ/G2L A/D converter in SW
> > trigger mode.
> >
> > A/D Converter block is a successive approximation analog-to-digital
> > converter with a 12-bit accuracy and supports a maximum of 8 input
> > channels.
> >
> > Signed-off-by: Lad Prabhakar <[e-mail]>
> > Reviewed-by: Biju Das <[e-mail]>
>
> Hi Lad,
>
> A few additional comments inline.
>
> Thanks,
>
> Jonathan
>
> > ---
> >  MAINTAINERS                 |   8 +
> >  drivers/iio/adc/Kconfig     |  10 +
> >  drivers/iio/adc/Makefile    |   1 +
> >  drivers/iio/adc/rzg2l_adc.c | 545 ++++++++++++++++++++++++++++++++++++
> >  4 files changed, 564 insertions(+)
> >  create mode 100644 drivers/iio/adc/rzg2l_adc.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 6c8be735cc91..6a52f9f4604c 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -15839,6 +15839,14 @@ L:   [e-mail]
> >  S:   Maintained
> >  F:   drivers/phy/renesas/phy-rcar-gen3-usb*.c
> >
> > +RENESAS RZ/G2L A/D DRIVER
> > +M:   Lad Prabhakar <[e-mail]>
> > +L:   [e-mail]
> > +L:   [e-mail]
> > +S:   Supported
> > +F:   Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
> > +F:   drivers/iio/adc/rzg2l_adc.c
> > +
> >  RESET CONTROLLER FRAMEWORK
> >  M:   Philipp Zabel <[e-mail]>
> >  S:   Maintained
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index db0c8fb60515..af168e1c9fdb 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -887,6 +887,16 @@ config ROCKCHIP_SARADC
> >         To compile this driver as a module, choose M here: the
> >         module will be called rockchip_saradc.
> >
> > +config RZG2L_ADC
> > +     tristate "Renesas RZ/G2L ADC driver"
> > +     depends on ARCH_R9A07G044 || COMPILE_TEST
> > +     help
> > +       Say yes here to build support for the ADC found in Renesas
> > +       RZ/G2L family.
> > +
> > +       To compile this driver as a module, choose M here: the
> > +       module will be called rzg2l_adc.
> > +
> >  config SC27XX_ADC
> >       tristate "Spreadtrum SC27xx series PMICs ADC"
> >       depends on MFD_SC27XX_PMIC || COMPILE_TEST
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index f70d877c555a..d68550f493e3 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -82,6 +82,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
> >  obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
> >  obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
> >  obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
> > +obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
> >  obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
> >  obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
> >  obj-$(CONFIG_STX104) += stx104.o
> > diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
> > new file mode 100644
> > index 000000000000..033cdec9e976
> > --- /dev/null
> > +++ b/drivers/iio/adc/rzg2l_adc.c
> > @@ -0,0 +1,545 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * RZ/G2L A/D Converter driver
> > + *
> > + *  Copyright (c) 2021 Renesas Electronics Europe GmbH
> > + *
> > + * Author: Lad Prabhakar <[e-mail]>
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
>
> Add mod_devicetable.h and drop the of specific headers
> as nothing in them used directly as far as I can tell.
>
OK.

> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/reset.h>
> > +
> > +#define DRIVER_NAME          "rzg2l-adc"
> > +
> > +#define RZG2L_ADM(n)                 ((n) * 0x4)
> > +#define RZG2L_ADM0_ADCE                      BIT(0)
> > +#define RZG2L_ADM0_ADBSY             BIT(1)
> > +#define RZG2L_ADM0_PWDWNB            BIT(2)
> > +#define RZG2L_ADM0_SRESB             BIT(15)
> > +#define RZG2L_ADM1_TRG                       BIT(0)
> > +#define RZG2L_ADM1_MS                        BIT(2)
> > +#define RZG2L_ADM1_BS                        BIT(4)
> > +#define RZG2L_ADM1_EGA_CLEAR         ~GENMASK(13, 12)
> > +#define RZG2L_ADM2_CHSEL_CLEAR               ~GENMASK(7, 0)
>
> I'd rather see these defined as _MASK and the
> inversion made explicit inline.
>
OK will use them as _MASK's and invert inline when required.

> > +#define RZG2L_ADM3_ADSMP             0x578
> > +#define RZG2L_ADM3_ADCMP             (0xe << 16)
> > +#define RZG2L_ADM3_ADIL_CLEAR                ~GENMASK(31, 24)
> > +
> > +#define RZG2L_ADINT                  0x20
> > +#define RZG2L_ADINT_CH_CLEAR         ~GENMASK(7, 0)
> > +#define RZG2L_ADINT_CSEEN            BIT(16)
> > +#define RZG2L_ADINT_INTS             BIT(31)
> > +#define RZG2L_ADSTS                  0x24
> > +#define RZG2L_ADINT_INTST_MASK               GENMASK(7, 0)
> > +#define RZG2L_ADSTS_CSEST            BIT(16)
> > +#define RZG2L_ADIVC                  0x28
> > +#define RZG2L_ADIVC_DIVADC_CLEAR     ~GENMASK(8, 0)
> > +#define RZG2L_ADIVC_DIVADC_4         0x4
>
> Perhaps adopt the _MASK and FIELD_PREP() approach to setting
> particular values.  That way it is obvious at the call site that
> DVADC_4 is a value within the DIVADC_MASK covered field.
>
Agreed will change that.

> > +#define RZG2L_ADFIL                  0x2c
> > +#define RZG2L_ADCR(n)                        (0x30 + ((n) * 0x4))
> > +#define RZG2L_ADCR_AD_MASK           GENMASK(11, 0)
> > +
> > +#define RZG2L_ADC_MAX_CHANNELS               8
> > +#define RZG2L_ADC_CHN_MASK           0x7
> > +#define RZG2L_ADC_TIMEOUT            usecs_to_jiffies(1 * 4)
> > +
> > +struct rzg2l_adc_data {
> > +     const struct iio_chan_spec *channels;
> > +     u8 num_channels;
> > +};
> > +
> > +struct rzg2l_adc {
> > +     void __iomem *base;
> > +     struct clk *pclk;
> > +     struct clk *adclk;
> > +     struct reset_control *presetn;
> > +     struct reset_control *adrstn;
> > +     struct completion completion;
> > +     const struct rzg2l_adc_data *data;
> > +     u16 last_val[RZG2L_ADC_MAX_CHANNELS];
> > +};
> > +
> > +static const char * const rzg2l_adc_channel_name[] = {
> > +     "adc0",
> Is it useful to expose these as labels to userspace?
> Seems unnecessary given they map directly to the channel
> numbers.
>
Exposing  them as this may vary depending on the wiring on the board,
so it  would be better for user space to know which channels are
available.

> > +     "adc1",
> > +     "adc2",
> > +     "adc3",
> > +     "adc4",
> > +     "adc5",
> > +     "adc6",
> > +     "adc7",
> > +};
> > +
> > +static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
> > +{
> > +     return readl(adc->base + reg);
> > +}
> > +
> > +static void rzg2l_adc_writel(struct rzg2l_adc *adc, unsigned int reg, u32 val)
> > +{
> > +     writel(val, adc->base + reg);
> > +}
> > +
> > +static void rzg2l_adc_pwr(struct rzg2l_adc *adc, bool on)
> > +{
> > +     u32 reg;
> > +
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> > +     if (on)
> > +             reg |= RZG2L_ADM0_PWDWNB;
> > +     else
> > +             reg &= ~RZG2L_ADM0_PWDWNB;
> > +     rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
> > +     udelay(2);
> > +}
> > +
> > +static void rzg2l_adc_start_stop(struct rzg2l_adc *adc, bool start)
> > +{
> > +     int timeout = 5;
> > +     u32 reg;
> > +
> > +     /* stop A/D conversion */
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> > +     if (start)
> > +             reg |= RZG2L_ADM0_ADCE;
> > +     else
> > +             reg &= ~RZG2L_ADM0_ADCE;
> > +     rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
> > +
> > +     if (start)
> > +             return;
> > +
> > +     do {
> > +             usleep_range(100, 200);
> > +             reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> > +             timeout--;
> > +             if (!timeout) {
> > +                     pr_err("%s stopping ADC timed out\n", __func__);
> > +                     break;
> > +             }
> > +     } while (((reg & RZG2L_ADM0_ADBSY) || (reg & RZG2L_ADM0_ADCE)));
> > +}
> > +
> > +static void rzg2l_set_trigger(struct rzg2l_adc *adc)
> > +{
> > +     u32 reg;
> > +
> > +     /* SW trigger */
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(1));
> > +     reg &= RZG2L_ADM1_EGA_CLEAR;
> > +     reg &= ~RZG2L_ADM1_BS;
> > +     reg |= RZG2L_ADM1_MS;
> > +     reg &= ~RZG2L_ADM1_TRG;
> > +     rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
> > +}
> > +
> > +static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
> > +{
> > +     u32 reg;
> > +
> > +     if (rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_ADBSY)
> > +             return -EBUSY;
> > +
> > +     rzg2l_set_trigger(adc);
> > +
> > +     /* select channel */
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(2));
> > +     reg &= RZG2L_ADM2_CHSEL_CLEAR;
> > +     reg |= BIT(ch);
> > +     rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
> > +
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
> > +     reg &= RZG2L_ADM3_ADIL_CLEAR;
> > +     reg |= RZG2L_ADM3_ADCMP;
> > +     reg |= RZG2L_ADM3_ADSMP;
>
> No loss in readability in combining the two lines above and shorter
> code is always good.  Having the mask on a separate line makes
> sense but the |= pair doesn't.
>
Agreed will move to the same line.

> What is a bit unusual here is you clear some bits then write different
> ones.  That is presumably relying on the fact that the ADCCMP part
> is always set to the same value.  That seems unwise to assume from
> a long term maintainability point of view.
>
The ADIL bits have to be set to zero, so I am clearing the ADIL bits
(bit 24-bits 31) and the ADCMP/ADSMP should be set to specific values
oxe/0x578 respectively.

> > +     rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
> > +
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADIVC);
> > +     reg &= RZG2L_ADIVC_DIVADC_CLEAR;
> > +     reg |= RZG2L_ADIVC_DIVADC_4;
> > +     rzg2l_adc_writel(adc, RZG2L_ADIVC, reg);
> > +
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADINT);
> > +     reg &= ~RZG2L_ADINT_INTS;
> > +     reg &= RZG2L_ADINT_CH_CLEAR;
> > +     reg |= RZG2L_ADINT_CSEEN;
> > +     reg |= BIT(ch);
> > +     rzg2l_adc_writel(adc, RZG2L_ADINT, reg);
> > +
> > +     return 0;
> > +}
> > +
> > +static int rzg2l_adc_set_power(struct iio_dev *indio_dev, bool on)
> > +{
> > +     struct device *dev = indio_dev->dev.parent;
> > +
> > +     if (on)
> > +             return pm_runtime_resume_and_get(dev);
> > +
> > +     return pm_runtime_put_sync(dev);
> > +}
> > +
> > +static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc, u8 ch)
> > +{
> > +     int ret;
> > +
> > +     ret = rzg2l_adc_set_power(indio_dev, true);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = rzg2l_adc_conversion_setup(adc, ch);
> > +     if (ret) {
> > +             rzg2l_adc_set_power(indio_dev, false);
> > +             return ret;
> > +     }
> > +
> > +     reinit_completion(&adc->completion);
> > +
> > +     rzg2l_adc_start_stop(adc, true);
> > +
> > +     if (!wait_for_completion_timeout(&adc->completion, RZG2L_ADC_TIMEOUT)) {
> > +             rzg2l_adc_writel(adc, RZG2L_ADINT,
> > +                              rzg2l_adc_readl(adc, RZG2L_ADINT) & RZG2L_ADINT_CH_CLEAR);
> > +             rzg2l_adc_start_stop(adc, false);
> > +             rzg2l_adc_set_power(indio_dev, false);
> > +             return -ETIMEDOUT;
> > +     }
> > +
> > +     return rzg2l_adc_set_power(indio_dev, false);
> > +}
> > +
> > +static int rzg2l_adc_read_raw(struct iio_dev *indio_dev,
> > +                           struct iio_chan_spec const *chan,
> > +                           int *val, int *val2, long mask)
> > +{
> > +     struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +     int ret;
> > +     u8 ch;
> > +
> > +     switch (mask) {
> > +     case IIO_CHAN_INFO_RAW:
> > +             if (chan->type != IIO_VOLTAGE)
> > +                     return -EINVAL;
> > +
> > +             ret = iio_device_claim_direct_mode(indio_dev);
> > +             if (ret)
> > +                     return ret;
> > +
> > +             ch = chan->channel & RZG2L_ADC_CHN_MASK;
> > +             ret = rzg2l_adc_conversion(indio_dev, adc, ch);
> > +             if (ret) {
> > +                     iio_device_release_direct_mode(indio_dev);
> > +                     return ret;
> > +             }
> > +             *val = adc->last_val[ch];
> > +             iio_device_release_direct_mode(indio_dev);
> > +
> > +             return IIO_VAL_INT;
> > +
> > +     default:
> > +             return -EINVAL;
> > +     }
> > +}
> > +
> > +static int rzg2l_adc_read_label(struct iio_dev *iio_dev,
> > +                             const struct iio_chan_spec *chan,
> > +                             char *label)
> > +{
> > +     if (chan->channel >= RZG2L_ADC_MAX_CHANNELS)
> > +             return -EINVAL;
> > +
> > +     return snprintf(label, PAGE_SIZE, "%s\n", rzg2l_adc_channel_name[chan->channel]);
>
> sysfs_emit()?.
>
OK

> > +}
> > +
> > +static const struct iio_info rzg2l_adc_iio_info = {
> > +     .read_raw = rzg2l_adc_read_raw,
> > +     .read_label = rzg2l_adc_read_label,
> > +};
> > +
> > +static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
> > +{
> > +     struct rzg2l_adc *adc = (struct rzg2l_adc *)dev_id;
> > +     u8 intst;
> > +     u32 reg;
> > +     u8 i;
> > +
> > +     reg = rzg2l_adc_readl(adc, RZG2L_ADSTS);
> > +     if (reg & RZG2L_ADSTS_CSEST) {
>
> Probably good to add a brief comment on what is going on in this check.
> Perhaps even an error print if it's an error path.
>
Agreed will add a comment, this condition happens on channel selection error.

> > +             rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
> > +             return IRQ_HANDLED;
> > +     }
> > +
> > +     intst = reg & RZG2L_ADINT_INTST_MASK;
> > +     if (!intst)
>
> I'm guessing this means spurious interrupt in which case IRQ_NONE
> so the core irq code knows about it.
>
Agreed IRQ_NONE should be returned.

> > +             return IRQ_HANDLED;
> > +
> > +     for (i = 0; i < RZG2L_ADC_MAX_CHANNELS; i++) {
> > +             if (intst & BIT(i))
>
> for_each_bit_set() and make intst a long so the types are right for
> that macro
>
>
Agreed will do.

> > +                     adc->last_val[i] = rzg2l_adc_readl(adc, RZG2L_ADCR(i)) & RZG2L_ADCR_AD_MASK;
> > +     }
> > +
> > +     rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
> > +
> > +     complete(&adc->completion);
> > +
> > +     return IRQ_HANDLED;
> > +}
> > +
> > +static int rzg2l_adc_parse_of(struct platform_device *pdev, struct rzg2l_adc *adc)
> > +{
> > +     struct iio_chan_spec *chan_array;
> > +     struct fwnode_handle *fwnode;
> > +     struct rzg2l_adc_data *data;
> > +     unsigned int channel;
> > +     int num_channels;
> > +     int ret;
> > +     u8 i;
> > +
> > +     data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> > +     if (!data)
> > +             return -ENOMEM;
> > +
> > +     num_channels = device_get_child_node_count(&pdev->dev);
> > +     if (!num_channels) {
> > +             dev_err(&pdev->dev, "no channel children\n");
> > +             return -ENODEV;
> > +     }
> > +
> > +     if (num_channels > RZG2L_ADC_MAX_CHANNELS) {
> > +             dev_err(&pdev->dev, "num of channel children out of range\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
> > +                               GFP_KERNEL);
> > +     if (!chan_array)
> > +             return -ENOMEM;
> > +
> > +     i = 0;
> > +     device_for_each_child_node(&pdev->dev, fwnode) {
> > +             ret = fwnode_property_read_u32(fwnode, "reg", &channel);
> > +             if (ret)
> > +                     return ret;
> > +
> > +             if (channel >= RZG2L_ADC_MAX_CHANNELS)
> > +                     return -EINVAL;
> > +
> > +             chan_array[i].type = IIO_VOLTAGE;
> > +             chan_array[i].indexed = 1;
> > +             chan_array[i].channel = channel;
> > +             chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> > +             chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
> > +             i++;
> > +     }
> > +
> > +     data->num_channels = num_channels;
> > +     data->channels = chan_array;
> > +     adc->data = data;
> > +
> > +     return 0;
> > +}
> > +
> > +static int rzg2l_adc_sw_reset(struct rzg2l_adc *adc)
> > +{
> > +     int timeout = 5;
> > +     u32 val;
> > +
> > +     val = rzg2l_adc_readl(adc, RZG2L_ADM(0));
> > +     val |= RZG2L_ADM0_SRESB;
> > +     rzg2l_adc_writel(adc, RZG2L_ADM(0), val);
> > +
> > +     while (!(rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_SRESB)) {
> > +             if (!timeout)
> > +                     return -EBUSY;
> > +             timeout--;
> > +             usleep_range(100, 200);
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int rzg2l_adc_probe(struct platform_device *pdev)
> > +{
> > +     struct device *dev = &pdev->dev;
> > +     struct iio_dev *indio_dev;
> > +     struct rzg2l_adc *adc;
> > +     int ret;
> > +     int irq;
> > +
> > +     indio_dev = devm_iio_device_alloc(dev, sizeof(*adc)
> > +     if (!indio_dev)
> > +             return -ENOMEM;
> > +
> > +     adc = iio_priv(indio_dev);
> > +
> > +     ret = rzg2l_adc_parse_of(pdev, adc);
>
> *_parse_properties() or *_parse_firmware()
> as it's not of specific now.
>
OK will rename it to rzg2l_adc_parse_properties().

> > +     if (ret)
> > +             return ret;
> > +
> > +     adc->base = devm_platform_ioremap_resource(pdev, 0);
> > +     if (IS_ERR(adc->base))
> > +             return PTR_ERR(adc->base);
> > +
> > +     irq = platform_get_irq(pdev, 0);
> > +     if (irq < 0) {
> > +             dev_err(dev, "no irq resource\n");
> > +             return irq;
> > +     }
> > +
> > +     adc->pclk = devm_clk_get(dev, "pclk");
> > +     if (IS_ERR(adc->pclk)) {
> > +             dev_err(dev, "Failed to get pclk");
> > +             return PTR_ERR(adc->pclk);
> > +     }
> > +
> > +     adc->adclk = devm_clk_get(dev, "adclk");
> > +     if (IS_ERR(adc->adclk)) {
> > +             dev_err(dev, "Failed to get adclk");
> > +             return PTR_ERR(adc->adclk);
> > +     }
> > +
> > +     adc->adrstn = devm_reset_control_get_exclusive(dev, "adrst-n");
> > +     if (IS_ERR(adc->adrstn)) {
> > +             dev_err(dev, "failed to get adrstn\n");
> > +             return PTR_ERR(adc->adrstn);
> > +     }
> > +
> > +     adc->presetn = devm_reset_control_get_exclusive(dev, "presetn");
> > +     if (IS_ERR(adc->presetn)) {
> > +             dev_err(dev, "failed to get presetn\n");
> > +             return PTR_ERR(adc->presetn);
> > +     }
> > +
> > +     ret = reset_control_deassert(adc->adrstn);
> > +     if (ret)
> > +             return ret;
>
> devm_add_action_or_reset() here to make the reasserting of these part
> of the automated cleanup.
>
OK will use devm_add_action_or_reset().

> > +
> > +     ret = reset_control_deassert(adc->presetn);
> > +     if (ret)
> > +             goto assert_adrstn;
> > +
> > +     ret = clk_prepare_enable(adc->pclk);
> > +     if (ret)
> > +             goto assert_presetn;
> > +
> > +     ret = rzg2l_adc_sw_reset(adc);
> > +     if (ret)
> > +             goto unprepare_pclk;
> > +
> > +     clk_disable_unprepare(adc->pclk);
>
> As below, reorder as:
>
>         ret = rzg2l_adc_sw_reset(adc);
>         clk_disable_unprepare(adc->pclk);
>         if (ret)
>                 goto assert_preset_n;
>
Agreed.

> > +
> > +     init_completion(&adc->completion);
> > +
> > +     platform_set_drvdata(pdev, indio_dev);
> > +
> > +     ret = devm_request_irq(dev, irq, rzg2l_adc_isr,
> > +                            0, dev_name(dev), adc);
>
> Another aspect of the comment below about mixing and matching between
> devm and not.  If the order of remove is not that opposite of probe
> then there should be a comment saying why.  There are far too many
> race conditions introduced by people doing things in a different order
> without carefully considering why.
>
Agreed will completely move to devm

> > +     if (ret < 0)
> > +             goto assert_presetn;
> > +
> > +     indio_dev->name = DRIVER_NAME;
> > +     indio_dev->info = &rzg2l_adc_iio_info;
> > +     indio_dev->modes = INDIO_DIRECT_MODE;
> > +     indio_dev->channels = adc->data->channels;
> > +     indio_dev->num_channels = adc->data->num_channels;
> > +
> > +     pm_runtime_enable(dev);
> > +
> > +     ret = devm_iio_device_register(dev, indio_dev);
> > +     if (ret)
> > +             goto err_iio_device_register;
> > +
> > +     return 0;
> > +
> > +unprepare_pclk:
> > +     clk_disable_unprepare(adc->pclk);
>
> Bad sign that you have this here and not in remove..
> When you have cases like this, it's normally better to
> either factor out the relevant code into a function
> that lets you do this call whether or not there is an
> error, or to just move this up to the relevant if statements.
>
As agreed above, will alter the code.

>
> > +err_iio_device_register:
> > +     pm_runtime_disable(dev);
> > +assert_presetn:
> > +     reset_control_assert(adc->presetn);
> > +assert_adrstn:
> > +     reset_control_assert(adc->adrstn);
> > +     return ret;
> > +}
> > +
> > +static int rzg2l_adc_remove(struct platform_device *pdev)
> > +{
> > +     struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> > +     struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +
> > +     reset_control_assert(adc->presetn);
> > +     reset_control_assert(adc->adrstn);
> > +     pm_runtime_disable(indio_dev->dev.parent);
>
> You can't mix and match devm managed and unmanaged like this.
> The userspace interfce is still exposed after you've put the
> device into reset which is unlikely to be a good idea.
>
> One option is to use devm_add_action_or_reset() to make
> this stuff happen in the managed flow, which happens after
> remove is done.  That would let you drop remove() entirely.
>
Agreed will use devm_add_action_or_reset() and get rid of remove callback().

Cheers,
Prabhakar
>
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct of_device_id rzg2l_adc_match[] = {
> > +     { .compatible = "renesas,rzg2l-adc",},
> > +     { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, rzg2l_adc_match);
> > +
> > +static int __maybe_unused rzg2l_adc_pm_runtime_suspend(struct device *dev)
> > +{
> > +     struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +     struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +
> > +     rzg2l_adc_pwr(adc, false);
> > +     clk_disable_unprepare(adc->adclk);
> > +     clk_disable_unprepare(adc->pclk);
> > +
> > +     return 0;
> > +}
> > +
> > +static int __maybe_unused rzg2l_adc_pm_runtime_resume(struct device *dev)
> > +{
> > +     struct iio_dev *indio_dev = dev_get_drvdata(dev);
> > +     struct rzg2l_adc *adc = iio_priv(indio_dev);
> > +     int ret;
> > +
> > +     ret = clk_prepare_enable(adc->pclk);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = clk_prepare_enable(adc->adclk);
> > +     if (ret)
> > +             return ret;
> > +
> > +     rzg2l_adc_pwr(adc, true);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct dev_pm_ops rzg2l_adc_pm_ops = {
> > +     SET_RUNTIME_PM_OPS(rzg2l_adc_pm_runtime_suspend,
> > +                        rzg2l_adc_pm_runtime_resume,
> > +                        NULL)
> > +};
> > +
> > +static struct platform_driver rzg2l_adc_driver = {
> > +     .probe          = rzg2l_adc_probe,
> > +     .remove         = rzg2l_adc_remove,
> > +     .driver         = {
> > +             .name           = DRIVER_NAME,
> > +             .of_match_table = rzg2l_adc_match,
> > +             .pm             = &rzg2l_adc_pm_ops,
> > +     },
> > +};
> > +
> > +module_platform_driver(rzg2l_adc_driver);
> > +
> > +MODULE_AUTHOR("Lad Prabhakar <[e-mail]>");
> > +MODULE_DESCRIPTION("Renesas RZ/G2L ADC driver");
> > +MODULE_LICENSE("GPL v2");
>

Jonathan Cameron July 25, 2021, 2:55 p.m. UTC | #3

On Sun, 25 Jul 2021 13:18:53 +0100
"Lad, Prabhakar" <[e-mail]> wrote:

> Hi Jonathan,
> 
> Thank you for the review.
> 
> On Sat, Jul 24, 2021 at 7:03 PM Jonathan Cameron <[e-mail]> wrote:
> >
> > On Mon, 19 Jul 2021 09:58:38 +0100
> > Lad Prabhakar <[e-mail]> wrote:
> >  
> > > Add ADC driver support for Renesas RZ/G2L A/D converter in SW
> > > trigger mode.
> > >
> > > A/D Converter block is a successive approximation analog-to-digital
> > > converter with a 12-bit accuracy and supports a maximum of 8 input
> > > channels.
> > >
> > > Signed-off-by: Lad Prabhakar <[e-mail]>
> > > Reviewed-by: Biju Das <[e-mail]>  
> >
> > Hi Lad,
> >
> > A few additional comments inline.
> >
> > Thanks,
> >
> > Jonathan
> >  

...

> 
> > > +#define RZG2L_ADFIL                  0x2c
> > > +#define RZG2L_ADCR(n)                        (0x30 + ((n) * 0x4))
> > > +#define RZG2L_ADCR_AD_MASK           GENMASK(11, 0)
> > > +
> > > +#define RZG2L_ADC_MAX_CHANNELS               8
> > > +#define RZG2L_ADC_CHN_MASK           0x7
> > > +#define RZG2L_ADC_TIMEOUT            usecs_to_jiffies(1 * 4)
> > > +
> > > +struct rzg2l_adc_data {
> > > +     const struct iio_chan_spec *channels;
> > > +     u8 num_channels;
> > > +};
> > > +
> > > +struct rzg2l_adc {
> > > +     void __iomem *base;
> > > +     struct clk *pclk;
> > > +     struct clk *adclk;
> > > +     struct reset_control *presetn;
> > > +     struct reset_control *adrstn;
> > > +     struct completion completion;
> > > +     const struct rzg2l_adc_data *data;
> > > +     u16 last_val[RZG2L_ADC_MAX_CHANNELS];
> > > +};
> > > +
> > > +static const char * const rzg2l_adc_channel_name[] = {
> > > +     "adc0",  
> > Is it useful to expose these as labels to userspace?
> > Seems unnecessary given they map directly to the channel
> > numbers.
> >  
> Exposing  them as this may vary depending on the wiring on the board,
> so it  would be better for user space to know which channels are
> available.

Hmm.  One thing to take into account is the IIO ABI doesn't require
channel numbers to be consecutive.  There are a few drivers where
they aren't due to channel optionality.

Perhaps that would make sense here?  If not, I'm fine with leaving
these as you have it.  They do no harm.

> 
> > > +     "adc1",
> > > +     "adc2",
> > > +     "adc3",
> > > +     "adc4",
> > > +     "adc5",
> > > +     "adc6",
> > > +     "adc7",
> > > +};
> > > +
...

> > > +static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
> > > +{
> > > +     u32 reg;
> > > +
> > > +     if (rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_ADBSY)
> > > +             return -EBUSY;
> > > +
> > > +     rzg2l_set_trigger(adc);
> > > +
> > > +     /* select channel */
> > > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(2));
> > > +     reg &= RZG2L_ADM2_CHSEL_CLEAR;
> > > +     reg |= BIT(ch);
> > > +     rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
> > > +
> > > +     reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
> > > +     reg &= RZG2L_ADM3_ADIL_CLEAR;
> > > +     reg |= RZG2L_ADM3_ADCMP;
> > > +     reg |= RZG2L_ADM3_ADSMP;  
> >
> > No loss in readability in combining the two lines above and shorter
> > code is always good.  Having the mask on a separate line makes
> > sense but the |= pair doesn't.
> >  
> Agreed will move to the same line.
> 
> > What is a bit unusual here is you clear some bits then write different
> > ones.  That is presumably relying on the fact that the ADCCMP part
> > is always set to the same value.  That seems unwise to assume from
> > a long term maintainability point of view.
> >  
> The ADIL bits have to be set to zero, so I am clearing the ADIL bits
> (bit 24-bits 31) and the ADCMP/ADSMP should be set to specific values
> oxe/0x578 respectively.

Understood, but from this 'local' bit of code it's not obvious that they don't
have other bits say, perhaps ADSMP is set to 0x483 for example by some
other code? (obviously it isn't, but it's nice to not have to sanity check
the rest of the driver to be sure!)  So normal thing to do would be to also
mask those bits out. 

I'm a bit curious on whether there are other bits in this register that make it
useful to do the read modify write cycle? (doesn't seem to be a public
datasheet from a quick google...)

> 
> > > +     rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
> > > +
> > > +     reg = rzg2l_adc_readl(adc, RZG2L_ADIVC);
> > > +     reg &= RZG2L_ADIVC_DIVADC_CLEAR;
> > > +     reg |= RZG2L_ADIVC_DIVADC_4;
> > > +     rzg2l_adc_writel(adc, RZG2L_ADIVC, reg);
> > > +
> > > +     reg = rzg2l_adc_readl(adc, RZG2L_ADINT);
> > > +     reg &= ~RZG2L_ADINT_INTS;
> > > +     reg &= RZG2L_ADINT_CH_CLEAR;
> > > +     reg |= RZG2L_ADINT_CSEEN;
> > > +     reg |= BIT(ch);
> > > +     rzg2l_adc_writel(adc, RZG2L_ADINT, reg);
> > > +
> > > +     return 0;
> > > +}
> > > +
...

Thanks,

Jonathan

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 6c8be735cc91..6a52f9f4604c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15839,6 +15839,14 @@  L:	[e-mail]
 S:	Maintained
 F:	drivers/phy/renesas/phy-rcar-gen3-usb*.c
 
+RENESAS RZ/G2L A/D DRIVER
+M:	Lad Prabhakar <[e-mail]>
+L:	[e-mail]
+L:	[e-mail]
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml
+F:	drivers/iio/adc/rzg2l_adc.c
+
 RESET CONTROLLER FRAMEWORK
 M:	Philipp Zabel <[e-mail]>
 S:	Maintained
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index db0c8fb60515..af168e1c9fdb 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -887,6 +887,16 @@  config ROCKCHIP_SARADC
 	  To compile this driver as a module, choose M here: the
 	  module will be called rockchip_saradc.
 
+config RZG2L_ADC
+	tristate "Renesas RZ/G2L ADC driver"
+	depends on ARCH_R9A07G044 || COMPILE_TEST
+	help
+	  Say yes here to build support for the ADC found in Renesas
+	  RZ/G2L family.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called rzg2l_adc.
+
 config SC27XX_ADC
 	tristate "Spreadtrum SC27xx series PMICs ADC"
 	depends on MFD_SC27XX_PMIC || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index f70d877c555a..d68550f493e3 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -82,6 +82,7 @@  obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
 obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
 obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
 obj-$(CONFIG_STX104) += stx104.o
diff --git a/drivers/iio/adc/rzg2l_adc.c b/drivers/iio/adc/rzg2l_adc.c
new file mode 100644
index 000000000000..033cdec9e976
--- /dev/null
+++ b/drivers/iio/adc/rzg2l_adc.c
@@ -0,0 +1,545 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RZ/G2L A/D Converter driver
+ *
+ *  Copyright (c) 2021 Renesas Electronics Europe GmbH
+ *
+ * Author: Lad Prabhakar <[e-mail]>
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+
+#define DRIVER_NAME		"rzg2l-adc"
+
+#define RZG2L_ADM(n)			((n) * 0x4)
+#define RZG2L_ADM0_ADCE			BIT(0)
+#define RZG2L_ADM0_ADBSY		BIT(1)
+#define RZG2L_ADM0_PWDWNB		BIT(2)
+#define RZG2L_ADM0_SRESB		BIT(15)
+#define RZG2L_ADM1_TRG			BIT(0)
+#define RZG2L_ADM1_MS			BIT(2)
+#define RZG2L_ADM1_BS			BIT(4)
+#define RZG2L_ADM1_EGA_CLEAR		~GENMASK(13, 12)
+#define RZG2L_ADM2_CHSEL_CLEAR		~GENMASK(7, 0)
+#define RZG2L_ADM3_ADSMP		0x578
+#define RZG2L_ADM3_ADCMP		(0xe << 16)
+#define RZG2L_ADM3_ADIL_CLEAR		~GENMASK(31, 24)
+
+#define RZG2L_ADINT			0x20
+#define RZG2L_ADINT_CH_CLEAR		~GENMASK(7, 0)
+#define RZG2L_ADINT_CSEEN		BIT(16)
+#define RZG2L_ADINT_INTS		BIT(31)
+#define RZG2L_ADSTS			0x24
+#define RZG2L_ADINT_INTST_MASK		GENMASK(7, 0)
+#define RZG2L_ADSTS_CSEST		BIT(16)
+#define RZG2L_ADIVC			0x28
+#define RZG2L_ADIVC_DIVADC_CLEAR	~GENMASK(8, 0)
+#define RZG2L_ADIVC_DIVADC_4		0x4
+#define RZG2L_ADFIL			0x2c
+#define RZG2L_ADCR(n)			(0x30 + ((n) * 0x4))
+#define RZG2L_ADCR_AD_MASK		GENMASK(11, 0)
+
+#define RZG2L_ADC_MAX_CHANNELS		8
+#define RZG2L_ADC_CHN_MASK		0x7
+#define RZG2L_ADC_TIMEOUT		usecs_to_jiffies(1 * 4)
+
+struct rzg2l_adc_data {
+	const struct iio_chan_spec *channels;
+	u8 num_channels;
+};
+
+struct rzg2l_adc {
+	void __iomem *base;
+	struct clk *pclk;
+	struct clk *adclk;
+	struct reset_control *presetn;
+	struct reset_control *adrstn;
+	struct completion completion;
+	const struct rzg2l_adc_data *data;
+	u16 last_val[RZG2L_ADC_MAX_CHANNELS];
+};
+
+static const char * const rzg2l_adc_channel_name[] = {
+	"adc0",
+	"adc1",
+	"adc2",
+	"adc3",
+	"adc4",
+	"adc5",
+	"adc6",
+	"adc7",
+};
+
+static unsigned int rzg2l_adc_readl(struct rzg2l_adc *adc, u32 reg)
+{
+	return readl(adc->base + reg);
+}
+
+static void rzg2l_adc_writel(struct rzg2l_adc *adc, unsigned int reg, u32 val)
+{
+	writel(val, adc->base + reg);
+}
+
+static void rzg2l_adc_pwr(struct rzg2l_adc *adc, bool on)
+{
+	u32 reg;
+
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
+	if (on)
+		reg |= RZG2L_ADM0_PWDWNB;
+	else
+		reg &= ~RZG2L_ADM0_PWDWNB;
+	rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
+	udelay(2);
+}
+
+static void rzg2l_adc_start_stop(struct rzg2l_adc *adc, bool start)
+{
+	int timeout = 5;
+	u32 reg;
+
+	/* stop A/D conversion */
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
+	if (start)
+		reg |= RZG2L_ADM0_ADCE;
+	else
+		reg &= ~RZG2L_ADM0_ADCE;
+	rzg2l_adc_writel(adc, RZG2L_ADM(0), reg);
+
+	if (start)
+		return;
+
+	do {
+		usleep_range(100, 200);
+		reg = rzg2l_adc_readl(adc, RZG2L_ADM(0));
+		timeout--;
+		if (!timeout) {
+			pr_err("%s stopping ADC timed out\n", __func__);
+			break;
+		}
+	} while (((reg & RZG2L_ADM0_ADBSY) || (reg & RZG2L_ADM0_ADCE)));
+}
+
+static void rzg2l_set_trigger(struct rzg2l_adc *adc)
+{
+	u32 reg;
+
+	/* SW trigger */
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(1));
+	reg &= RZG2L_ADM1_EGA_CLEAR;
+	reg &= ~RZG2L_ADM1_BS;
+	reg |= RZG2L_ADM1_MS;
+	reg &= ~RZG2L_ADM1_TRG;
+	rzg2l_adc_writel(adc, RZG2L_ADM(1), reg);
+}
+
+static int rzg2l_adc_conversion_setup(struct rzg2l_adc *adc, u8 ch)
+{
+	u32 reg;
+
+	if (rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_ADBSY)
+		return -EBUSY;
+
+	rzg2l_set_trigger(adc);
+
+	/* select channel */
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(2));
+	reg &= RZG2L_ADM2_CHSEL_CLEAR;
+	reg |= BIT(ch);
+	rzg2l_adc_writel(adc, RZG2L_ADM(2), reg);
+
+	reg = rzg2l_adc_readl(adc, RZG2L_ADM(3));
+	reg &= RZG2L_ADM3_ADIL_CLEAR;
+	reg |= RZG2L_ADM3_ADCMP;
+	reg |= RZG2L_ADM3_ADSMP;
+	rzg2l_adc_writel(adc, RZG2L_ADM(3), reg);
+
+	reg = rzg2l_adc_readl(adc, RZG2L_ADIVC);
+	reg &= RZG2L_ADIVC_DIVADC_CLEAR;
+	reg |= RZG2L_ADIVC_DIVADC_4;
+	rzg2l_adc_writel(adc, RZG2L_ADIVC, reg);
+
+	reg = rzg2l_adc_readl(adc, RZG2L_ADINT);
+	reg &= ~RZG2L_ADINT_INTS;
+	reg &= RZG2L_ADINT_CH_CLEAR;
+	reg |= RZG2L_ADINT_CSEEN;
+	reg |= BIT(ch);
+	rzg2l_adc_writel(adc, RZG2L_ADINT, reg);
+
+	return 0;
+}
+
+static int rzg2l_adc_set_power(struct iio_dev *indio_dev, bool on)
+{
+	struct device *dev = indio_dev->dev.parent;
+
+	if (on)
+		return pm_runtime_resume_and_get(dev);
+
+	return pm_runtime_put_sync(dev);
+}
+
+static int rzg2l_adc_conversion(struct iio_dev *indio_dev, struct rzg2l_adc *adc, u8 ch)
+{
+	int ret;
+
+	ret = rzg2l_adc_set_power(indio_dev, true);
+	if (ret)
+		return ret;
+
+	ret = rzg2l_adc_conversion_setup(adc, ch);
+	if (ret) {
+		rzg2l_adc_set_power(indio_dev, false);
+		return ret;
+	}
+
+	reinit_completion(&adc->completion);
+
+	rzg2l_adc_start_stop(adc, true);
+
+	if (!wait_for_completion_timeout(&adc->completion, RZG2L_ADC_TIMEOUT)) {
+		rzg2l_adc_writel(adc, RZG2L_ADINT,
+				 rzg2l_adc_readl(adc, RZG2L_ADINT) & RZG2L_ADINT_CH_CLEAR);
+		rzg2l_adc_start_stop(adc, false);
+		rzg2l_adc_set_power(indio_dev, false);
+		return -ETIMEDOUT;
+	}
+
+	return rzg2l_adc_set_power(indio_dev, false);
+}
+
+static int rzg2l_adc_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val, int *val2, long mask)
+{
+	struct rzg2l_adc *adc = iio_priv(indio_dev);
+	int ret;
+	u8 ch;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type != IIO_VOLTAGE)
+			return -EINVAL;
+
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		ch = chan->channel & RZG2L_ADC_CHN_MASK;
+		ret = rzg2l_adc_conversion(indio_dev, adc, ch);
+		if (ret) {
+			iio_device_release_direct_mode(indio_dev);
+			return ret;
+		}
+		*val = adc->last_val[ch];
+		iio_device_release_direct_mode(indio_dev);
+
+		return IIO_VAL_INT;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rzg2l_adc_read_label(struct iio_dev *iio_dev,
+				const struct iio_chan_spec *chan,
+				char *label)
+{
+	if (chan->channel >= RZG2L_ADC_MAX_CHANNELS)
+		return -EINVAL;
+
+	return snprintf(label, PAGE_SIZE, "%s\n", rzg2l_adc_channel_name[chan->channel]);
+}
+
+static const struct iio_info rzg2l_adc_iio_info = {
+	.read_raw = rzg2l_adc_read_raw,
+	.read_label = rzg2l_adc_read_label,
+};
+
+static irqreturn_t rzg2l_adc_isr(int irq, void *dev_id)
+{
+	struct rzg2l_adc *adc = (struct rzg2l_adc *)dev_id;
+	u8 intst;
+	u32 reg;
+	u8 i;
+
+	reg = rzg2l_adc_readl(adc, RZG2L_ADSTS);
+	if (reg & RZG2L_ADSTS_CSEST) {
+		rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
+		return IRQ_HANDLED;
+	}
+
+	intst = reg & RZG2L_ADINT_INTST_MASK;
+	if (!intst)
+		return IRQ_HANDLED;
+
+	for (i = 0; i < RZG2L_ADC_MAX_CHANNELS; i++) {
+		if (intst & BIT(i))
+			adc->last_val[i] = rzg2l_adc_readl(adc, RZG2L_ADCR(i)) & RZG2L_ADCR_AD_MASK;
+	}
+
+	rzg2l_adc_writel(adc, RZG2L_ADSTS, reg);
+
+	complete(&adc->completion);
+
+	return IRQ_HANDLED;
+}
+
+static int rzg2l_adc_parse_of(struct platform_device *pdev, struct rzg2l_adc *adc)
+{
+	struct iio_chan_spec *chan_array;
+	struct fwnode_handle *fwnode;
+	struct rzg2l_adc_data *data;
+	unsigned int channel;
+	int num_channels;
+	int ret;
+	u8 i;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	num_channels = device_get_child_node_count(&pdev->dev);
+	if (!num_channels) {
+		dev_err(&pdev->dev, "no channel children\n");
+		return -ENODEV;
+	}
+
+	if (num_channels > RZG2L_ADC_MAX_CHANNELS) {
+		dev_err(&pdev->dev, "num of channel children out of range\n");
+		return -EINVAL;
+	}
+
+	chan_array = devm_kcalloc(&pdev->dev, num_channels, sizeof(*chan_array),
+				  GFP_KERNEL);
+	if (!chan_array)
+		return -ENOMEM;
+
+	i = 0;
+	device_for_each_child_node(&pdev->dev, fwnode) {
+		ret = fwnode_property_read_u32(fwnode, "reg", &channel);
+		if (ret)
+			return ret;
+
+		if (channel >= RZG2L_ADC_MAX_CHANNELS)
+			return -EINVAL;
+
+		chan_array[i].type = IIO_VOLTAGE;
+		chan_array[i].indexed = 1;
+		chan_array[i].channel = channel;
+		chan_array[i].info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
+		chan_array[i].datasheet_name = rzg2l_adc_channel_name[channel];
+		i++;
+	}
+
+	data->num_channels = num_channels;
+	data->channels = chan_array;
+	adc->data = data;
+
+	return 0;
+}
+
+static int rzg2l_adc_sw_reset(struct rzg2l_adc *adc)
+{
+	int timeout = 5;
+	u32 val;
+
+	val = rzg2l_adc_readl(adc, RZG2L_ADM(0));
+	val |= RZG2L_ADM0_SRESB;
+	rzg2l_adc_writel(adc, RZG2L_ADM(0), val);
+
+	while (!(rzg2l_adc_readl(adc, RZG2L_ADM(0)) & RZG2L_ADM0_SRESB)) {
+		if (!timeout)
+			return -EBUSY;
+		timeout--;
+		usleep_range(100, 200);
+	}
+
+	return 0;
+}
+
+static int rzg2l_adc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct iio_dev *indio_dev;
+	struct rzg2l_adc *adc;
+	int ret;
+	int irq;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	adc = iio_priv(indio_dev);
+
+	ret = rzg2l_adc_parse_of(pdev, adc);
+	if (ret)
+		return ret;
+
+	adc->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(adc->base))
+		return PTR_ERR(adc->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev, "no irq resource\n");
+		return irq;
+	}
+
+	adc->pclk = devm_clk_get(dev, "pclk");
+	if (IS_ERR(adc->pclk)) {
+		dev_err(dev, "Failed to get pclk");
+		return PTR_ERR(adc->pclk);
+	}
+
+	adc->adclk = devm_clk_get(dev, "adclk");
+	if (IS_ERR(adc->adclk)) {
+		dev_err(dev, "Failed to get adclk");
+		return PTR_ERR(adc->adclk);
+	}
+
+	adc->adrstn = devm_reset_control_get_exclusive(dev, "adrst-n");
+	if (IS_ERR(adc->adrstn)) {
+		dev_err(dev, "failed to get adrstn\n");
+		return PTR_ERR(adc->adrstn);
+	}
+
+	adc->presetn = devm_reset_control_get_exclusive(dev, "presetn");
+	if (IS_ERR(adc->presetn)) {
+		dev_err(dev, "failed to get presetn\n");
+		return PTR_ERR(adc->presetn);
+	}
+
+	ret = reset_control_deassert(adc->adrstn);
+	if (ret)
+		return ret;
+
+	ret = reset_control_deassert(adc->presetn);
+	if (ret)
+		goto assert_adrstn;
+
+	ret = clk_prepare_enable(adc->pclk);
+	if (ret)
+		goto assert_presetn;
+
+	ret = rzg2l_adc_sw_reset(adc);
+	if (ret)
+		goto unprepare_pclk;
+
+	clk_disable_unprepare(adc->pclk);
+
+	init_completion(&adc->completion);
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	ret = devm_request_irq(dev, irq, rzg2l_adc_isr,
+			       0, dev_name(dev), adc);
+	if (ret < 0)
+		goto assert_presetn;
+
+	indio_dev->name = DRIVER_NAME;
+	indio_dev->info = &rzg2l_adc_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = adc->data->channels;
+	indio_dev->num_channels = adc->data->num_channels;
+
+	pm_runtime_enable(dev);
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		goto err_iio_device_register;
+
+	return 0;
+
+unprepare_pclk:
+	clk_disable_unprepare(adc->pclk);
+err_iio_device_register:
+	pm_runtime_disable(dev);
+assert_presetn:
+	reset_control_assert(adc->presetn);
+assert_adrstn:
+	reset_control_assert(adc->adrstn);
+	return ret;
+}
+
+static int rzg2l_adc_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct rzg2l_adc *adc = iio_priv(indio_dev);
+
+	reset_control_assert(adc->presetn);
+	reset_control_assert(adc->adrstn);
+	pm_runtime_disable(indio_dev->dev.parent);
+
+	return 0;
+}
+
+static const struct of_device_id rzg2l_adc_match[] = {
+	{ .compatible = "renesas,rzg2l-adc",},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzg2l_adc_match);
+
+static int __maybe_unused rzg2l_adc_pm_runtime_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rzg2l_adc *adc = iio_priv(indio_dev);
+
+	rzg2l_adc_pwr(adc, false);
+	clk_disable_unprepare(adc->adclk);
+	clk_disable_unprepare(adc->pclk);
+
+	return 0;
+}
+
+static int __maybe_unused rzg2l_adc_pm_runtime_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct rzg2l_adc *adc = iio_priv(indio_dev);
+	int ret;
+
+	ret = clk_prepare_enable(adc->pclk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(adc->adclk);
+	if (ret)
+		return ret;
+
+	rzg2l_adc_pwr(adc, true);
+
+	return 0;
+}
+
+static const struct dev_pm_ops rzg2l_adc_pm_ops = {
+	SET_RUNTIME_PM_OPS(rzg2l_adc_pm_runtime_suspend,
+			   rzg2l_adc_pm_runtime_resume,
+			   NULL)
+};
+
+static struct platform_driver rzg2l_adc_driver = {
+	.probe		= rzg2l_adc_probe,
+	.remove		= rzg2l_adc_remove,
+	.driver		= {
+		.name		= DRIVER_NAME,
+		.of_match_table = rzg2l_adc_match,
+		.pm		= &rzg2l_adc_pm_ops,
+	},
+};
+
+module_platform_driver(rzg2l_adc_driver);
+
+MODULE_AUTHOR("Lad Prabhakar <[e-mail]>");
+MODULE_DESCRIPTION("Renesas RZ/G2L ADC driver");
+MODULE_LICENSE("GPL v2");