[2/3] thermal: Add Mediatek thermal controller support

Commit Message

Sascha Hauer Sept. 23, 2015, 1:37 p.m. UTC

This adds support for the Mediatek thermal controller found on MT8173
and likely other SoCs.
The controller is a bit special. It does not have its own ADC, instead
it controls the on-SoC AUXADC via AHB bus accesses. For this reason
we need the physical address of the AUXADC. Also it controls a mux
using AHB bus accesses, so we need the APMIXEDSYS physical address aswell.

Signed-off-by: Sascha Hauer <[e-mail]>
Reviewed-by: Daniel Kurtz <[e-mail]>
---
 drivers/thermal/Kconfig       |   8 +
 drivers/thermal/Makefile      |   1 +
 drivers/thermal/mtk_thermal.c | 537 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 546 insertions(+)
 create mode 100644 drivers/thermal/mtk_thermal.c

Comments

Vladimir Zapolskiy Sept. 23, 2015, 6:31 p.m. UTC | #1

Hi Sascha,

On 23.09.2015 16:37, Sascha Hauer wrote:
> This adds support for the Mediatek thermal controller found on MT8173
> and likely other SoCs.
> The controller is a bit special. It does not have its own ADC, instead
> it controls the on-SoC AUXADC via AHB bus accesses. For this reason
> we need the physical address of the AUXADC. Also it controls a mux
> using AHB bus accesses, so we need the APMIXEDSYS physical address aswell.
> 
> Signed-off-by: Sascha Hauer <[e-mail]>
> Reviewed-by: Daniel Kurtz <[e-mail]>
> ---
>  drivers/thermal/Kconfig       |   8 +
>  drivers/thermal/Makefile      |   1 +
>  drivers/thermal/mtk_thermal.c | 537 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 546 insertions(+)
>  create mode 100644 drivers/thermal/mtk_thermal.c
> 

[snip]

> +
> +	auxadc = of_parse_phandle(np, "mediatek,auxadc", 0);
> +	if (!auxadc) {
> +		dev_err(&pdev->dev, "missing auxadc node\n");
> +		return -ENODEV;
> +	}
> +
> +	auxadc_phys_base = of_get_phys_base(auxadc);

in case of OF_DYNAMIC enabled of_parse_phandle() requires of_node_put(),
which is fine to place right here.

> +	if (auxadc_phys_base == OF_BAD_ADDR) {
> +		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
> +		return -EINVAL;
> +	}
> +

[snip]

> +
> +	/*
> +	 * These calibration values should finally be provided by the
> +	 * firmware or fuses. For now use default values.
> +	 */
> +	mt->calib_slope = -123;
> +	mt->calib_offset = 465124;
> +
> +	for (i = 0; i < MT8173_NUM_ZONES; i++)
> +		mtk_thermal_init_bank(mt, i, apmixed_phys_base, auxadc_phys_base);
> +
> +	platform_set_drvdata(pdev, mt);
> +
> +	for (i = 0; i < MT8173_NUM_ZONES; i++) {
> +		struct mtk_thermal_bank *bank = &mt->banks[i];
> +
> +		bank->tzd = thermal_zone_of_sensor_register(&pdev->dev, i, bank,
> +				&mtk_thermal_ops);

I would propose to add return value checks here, otherwise there might
be an oops in mtk_thermal_remove(), if something goes wrong.

--
With best wishes,
Vladimir
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Eduardo Valentin Sept. 29, 2015, 11:04 p.m. UTC | #2

On Wed, Sep 23, 2015 at 03:37:42PM +0200, Sascha Hauer wrote:
> This adds support for the Mediatek thermal controller found on MT8173
> and likely other SoCs.
> The controller is a bit special. It does not have its own ADC, instead
> it controls the on-SoC AUXADC via AHB bus accesses. For this reason
> we need the physical address of the AUXADC. Also it controls a mux
> using AHB bus accesses, so we need the APMIXEDSYS physical address aswell.
> 
> Signed-off-by: Sascha Hauer <[e-mail]>
> Reviewed-by: Daniel Kurtz <[e-mail]>
> ---
>  drivers/thermal/Kconfig       |   8 +
>  drivers/thermal/Makefile      |   1 +
>  drivers/thermal/mtk_thermal.c | 537 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 546 insertions(+)
>  create mode 100644 drivers/thermal/mtk_thermal.c
> 
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 0390044..dadd1eb 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -348,6 +348,14 @@ config INTEL_PCH_THERMAL
>  	  Thermal reporting device will provide temperature reading,
>  	  programmable trip points and other information.
>  
> +config MTK_THERMAL
> +	tristate "Temperature sensor driver for mediatek SoCs"
> +	depends on ARCH_MEDIATEK || COMPILE_TEST
> +	default y
> +	help
> +	  Enable this option if you want to have support for thermal management
> +	  controller present in Mediatek SoCs
> +
>  menu "Texas Instruments thermal drivers"
>  source "drivers/thermal/ti-soc-thermal/Kconfig"
>  endmenu
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 26f1608..5f979e7 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -45,3 +45,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
>  obj-$(CONFIG_ST_THERMAL)	+= st/
>  obj-$(CONFIG_TEGRA_SOCTHERM)	+= tegra_soctherm.o
>  obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
> +obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o
> diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> new file mode 100644
> index 0000000..6be1a6c
> --- /dev/null
> +++ b/drivers/thermal/mtk_thermal.c
> @@ -0,0 +1,537 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: Hanyi Wu <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>

You dont seam to be using this header. Can you please clean up to have
only the headers you need?

> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/thermal.h>
> +#include <linux/reset.h>
> +#include <linux/time.h>
> +#include <linux/types.h>
> +#include <dt-bindings/thermal/mt8173.h>
> +
> +/* AUXADC Registers */
> +#define AUXADC_CON0_V		0x000
> +#define AUXADC_CON1_V		0x004
> +#define AUXADC_CON1_SET_V	0x008
> +#define AUXADC_CON1_CLR_V	0x00c
> +#define AUXADC_CON2_V		0x010
> +#define AUXADC_DATA(channel)	(0x14 + (channel) * 4)
> +#define AUXADC_MISC_V		0x094
> +
> +#define AUXADC_CON1_CHANNEL(x)	BIT(x)
> +
> +#define APMIXED_SYS_TS_CON1	0x604
> +
> +/* Thermal Controller Registers */
> +#define TEMP_MONCTL0		0x000
> +#define TEMP_MONCTL1		0x004
> +#define TEMP_MONCTL2		0x008
> +#define TEMP_MONIDET0		0x014
> +#define TEMP_MONIDET1		0x018
> +#define TEMP_MSRCTL0		0x038
> +#define TEMP_AHBPOLL		0x040
> +#define TEMP_AHBTO		0x044
> +#define TEMP_ADCPNP0		0x048
> +#define TEMP_ADCPNP1		0x04c
> +#define TEMP_ADCPNP2		0x050
> +#define TEMP_ADCPNP3		0x0b4
> +
> +#define TEMP_ADCMUX		0x054
> +#define TEMP_ADCEN		0x060
> +#define TEMP_PNPMUXADDR		0x064
> +#define TEMP_ADCMUXADDR		0x068
> +#define TEMP_ADCENADDR		0x074
> +#define TEMP_ADCVALIDADDR	0x078
> +#define TEMP_ADCVOLTADDR	0x07c
> +#define TEMP_RDCTRL		0x080
> +#define TEMP_ADCVALIDMASK	0x084
> +#define TEMP_ADCVOLTAGESHIFT	0x088
> +#define TEMP_ADCWRITECTRL	0x08c
> +#define TEMP_MSR0		0x090
> +#define TEMP_MSR1		0x094
> +#define TEMP_MSR2		0x098
> +#define TEMP_MSR3		0x0B8
> +
> +#define TEMP_SPARE0		0x0f0
> +
> +#define PTPCORESEL		0x400
> +
> +#define TEMP_MONCTL1_PERIOD_UNIT(x)	((x) & 0x3ff)
> +
> +#define TEMP_MONCTL2_FILTER_INTERVAL(x)	(((x) & 0x3ff)) << 16
> +#define TEMP_MONCTL2_SENSOR_INTERVAL(x)	((x) & 0x3ff)
> +
> +#define TEMP_AHBPOLL_ADC_POLL_INTERVAL(x)	(x)
> +
> +#define TEMP_ADCWRITECTRL_ADC_PNP_WRITE		BIT(0)
> +#define TEMP_ADCWRITECTRL_ADC_MUX_WRITE		BIT(1)
> +
> +#define TEMP_ADCVALIDMASK_VALID_HIGH		BIT(5)
> +#define TEMP_ADCVALIDMASK_VALID_POS(bit)	(bit)
> +
> +#define MT8173_TS1	0
> +#define MT8173_TS2	1
> +#define MT8173_TS3	2
> +#define MT8173_TS4	3
> +#define MT8173_TSABB	4
> +
> +/* AUXADC channel 11 is used for the temperature sensors */
> +#define MT8173_TEMP_AUXADC_CHANNEL	11
> +
> +/* The total number of temperature sensors in the MT8173 */
> +#define MT8173_NUM_SENSORS		5
> +
> +/* The number of banks in the MT8173 */
> +#define MT8173_NUM_ZONES		4
> +
> +/* The number of sensing points per bank */
> +#define MT8173_NUM_SENSORS_PER_ZONE	4
> +
> +#define THERMAL_NAME    "mtk-thermal"
> +
> +struct mtk_thermal;
> +
> +struct mtk_thermal_bank {
> +	struct mtk_thermal *mt;
> +	struct thermal_zone_device *tzd;
> +	int id;
> +};
> +
> +struct mtk_thermal {
> +	struct device *dev;
> +	void __iomem *thermal_base;
> +
> +	struct clk *clk_peri_therm;
> +	struct clk *clk_auxadc;
> +
> +	struct mtk_thermal_bank banks[MT8173_NUM_ZONES];
> +
> +	struct mutex lock;
> +
> +	/* Calibration values */
> +	int calib_slope;
> +	int calib_offset;
> +};
> +
> +struct mtk_thermal_bank_cfg {
> +	unsigned int num_sensors;
> +	unsigned int sensors[MT8173_NUM_SENSORS_PER_ZONE];
> +};
> +
> +static const int sensor_mux_values[MT8173_NUM_SENSORS] = { 0, 1, 2, 3, 16 };
> +
> +/*
> + * The MT8173 thermal controller has four banks. Each bank can read up to
> + * four temperature sensors simultaneously. The MT8173 has a total of 5
> + * temperature sensors. We use each bank to measure a certain area of the
> + * SoC. Since TS2 is located centrally in the SoC it is influenced by multiple
> + * areas, hence is used in different banks.
> + */
> +static const struct mtk_thermal_bank_cfg bank_data[] = {
> +	[MT8173_THERMAL_ZONE_CA53] = {
> +		.num_sensors = 2,
> +		.sensors = { MT8173_TS2, MT8173_TS3 },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_CA57] = {
> +		.num_sensors = 2,
> +		.sensors = { MT8173_TS2, MT8173_TS4 },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_GPU] = {
> +		.num_sensors = 3,
> +		.sensors = { MT8173_TS1, MT8173_TS2, MT8173_TSABB },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_CORE] = {
> +		.num_sensors = 1,
> +		.sensors = { MT8173_TS2 },
> +	},
> +};
> +
> +struct mtk_thermal_sense_point {
> +	int msr;
> +	int adcpnp;
> +};
> +
> +static const struct mtk_thermal_sense_point
> +		sensing_points[MT8173_NUM_SENSORS_PER_ZONE] = {
> +	{
> +		.msr = TEMP_MSR0,
> +		.adcpnp = TEMP_ADCPNP0,
> +	}, {
> +		.msr = TEMP_MSR1,
> +		.adcpnp = TEMP_ADCPNP1,
> +	}, {
> +		.msr = TEMP_MSR2,
> +		.adcpnp = TEMP_ADCPNP2,
> +	}, {
> +		.msr = TEMP_MSR3,
> +		.adcpnp = TEMP_ADCPNP3,
> +	},
> +};
> +
> +/**
> + * raw_to_mcelsius - convert a raw ADC value to mcelsius
> + * @mt:		The thermal controller
> + * @raw:	raw ADC value
> + *
> + * This converts the raw ADC value to mcelsius using the SoC specific
> + * calibration constants
> + */
> +static int raw_to_mcelsius(struct mtk_thermal *mt, u32 raw)
> +{
> +	return mt->calib_offset + mt->calib_slope * (raw & 0xfff);
> +}
> +
> +/**
> + * mtk_thermal_get_bank - get bank
> + * @bank:	The bank
> + *
> + * The bank registers are banked, we have to select a bank in the
> + * PTPCORESEL register to access it.
> + */
> +static void mtk_thermal_get_bank(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +	u32 val;
> +
> +	mutex_lock(&mt->lock);
> +
> +	val = readl(mt->thermal_base + PTPCORESEL);
> +	val &= ~0xf;
> +	val |= bank->id;
> +	writel(val, mt->thermal_base + PTPCORESEL);
> +}
> +
> +/**
> + * mtk_thermal_put_bank - release bank
> + * @bank:	The bank
> + *
> + * release a bank previously taken with mtk_thermal_get_bank,
> + */
> +static void mtk_thermal_put_bank(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +
> +	mutex_unlock(&mt->lock);
> +}
> +
> +/**
> + * mtk_thermal_bank_temperature - get the temperature of a bank
> + * @bank:	The bank
> + *
> + * The temperature of a bank is considered the maximum temperature of
> + * the sensors associated to the bank.
> + */
> +static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +	int temp, i, max;
> +	u32 raw;
> +
> +	temp = max = INT_MIN;
> +
> +	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
> +		raw = readl(mt->thermal_base + sensing_points[i].msr);
> +
> +		temp = raw_to_mcelsius(mt, raw);
> +
> +		/*
> +		 * The first read of a sensor often contains very high bogus
> +		 * temperature value. Filter these out so that the system does
> +		 * not immediately shut down.
> +		 */
> +		if (temp > 200000)

Ok... How about after the first read?  is > 200000 a valid (supported) value range? 

Just trying to understand if the cap can be kept on all cases.

> +			temp = 0;
> +
> +		if (temp > max)
> +			max = temp;
> +	}
> +
> +	return max;
> +}
> +
> +static int mtk_read_temp(void *data, int *temp)
> +{
> +	struct mtk_thermal_bank *bank = data;
> +
> +	mtk_thermal_get_bank(bank);
> +
> +	*temp = mtk_thermal_bank_temperature(bank);
> +
> +	mtk_thermal_put_bank(bank);
> +
> +	return 0;
> +}
> +
> +static const struct thermal_zone_of_device_ops mtk_thermal_ops = {
> +	.get_temp = mtk_read_temp,
> +};
> +
> +static void mtk_thermal_init_bank(struct mtk_thermal *mt, int num,
> +		u32 apmixed_phys_base, u32 auxadc_phys_base)
> +{
> +	struct mtk_thermal_bank *bank = &mt->banks[num];
> +	const struct mtk_thermal_bank_cfg *cfg = &bank_data[num];
> +	int i;
> +
> +	bank->id = num;
> +	bank->mt = mt;
> +
> +	mtk_thermal_get_bank(bank);
> +
> +	/* bus clock 66M counting unit is 12 * 15.15ns * 256 = 46.540us */
> +	writel(TEMP_MONCTL1_PERIOD_UNIT(12), mt->thermal_base + TEMP_MONCTL1);
> +
> +	/*
> +	 * filt interval is 1 * 46.540us = 46.54us,
> +	 * sen interval is 429 * 46.540us = 19.96ms
> +	 */
> +	writel(TEMP_MONCTL2_FILTER_INTERVAL(1) |
> +			TEMP_MONCTL2_SENSOR_INTERVAL(429),
> +			mt->thermal_base + TEMP_MONCTL2);
> +
> +	/* poll is set to 10u */
> +	writel(TEMP_AHBPOLL_ADC_POLL_INTERVAL(768),
> +			mt->thermal_base + TEMP_AHBPOLL);
> +
> +	/* temperature sampling control, 1 sample */
> +	writel(0x00000000, mt->thermal_base + TEMP_MSRCTL0);
> +
> +	/* exceed this polling time, IRQ would be inserted */
> +	writel(0xffffffff, mt->thermal_base + TEMP_AHBTO);
> +
> +	/* number of interrupts per event, 1 is enough */
> +	writel(0x0, mt->thermal_base + TEMP_MONIDET0);
> +	writel(0x0, mt->thermal_base + TEMP_MONIDET1);
> +
> +	/*
> +	 * The MT8173 thermal controller does not have its own ADC. Instead it
> +	 * uses AHB bus accesses to control the AUXADC. To do this the thermal
> +	 * controller has to be programmed with the physical addresses of the
> +	 * AUXADC registers and with the various bit positions in the AUXADC.
> +	 * Also the thermal controller controls a mux in the APMIXEDSYS register
> +	 * space.
> +	 */
> +
> +	/*
> +	 * this value will be stored to TEMP_PNPMUXADDR (TEMP_SPARE0)
> +	 * automatically by hw
> +	 */
> +	writel(BIT(MT8173_TEMP_AUXADC_CHANNEL), mt->thermal_base + TEMP_ADCMUX);
> +
> +	/* AHB address for auxadc mux selection */
> +	writel(auxadc_phys_base + AUXADC_CON1_CLR_V,
> +			mt->thermal_base + TEMP_ADCMUXADDR);
> +
> +	/* AHB address for pnp sensor mux selection */
> +	writel(apmixed_phys_base + APMIXED_SYS_TS_CON1,
> +			mt->thermal_base + TEMP_PNPMUXADDR);
> +
> +	/* AHB value for auxadc enable */
> +	writel(BIT(MT8173_TEMP_AUXADC_CHANNEL), mt->thermal_base + TEMP_ADCEN);
> +
> +	/* AHB address for auxadc enable (channel 0 immediate mode selected) */
> +	writel(auxadc_phys_base + AUXADC_CON1_SET_V,
> +			mt->thermal_base + TEMP_ADCENADDR);
> +
> +	/* AHB address for auxadc valid bit */
> +	writel(auxadc_phys_base + AUXADC_DATA(MT8173_TEMP_AUXADC_CHANNEL),
> +			mt->thermal_base + TEMP_ADCVALIDADDR);
> +
> +	/* AHB address for auxadc voltage output */
> +	writel(auxadc_phys_base + AUXADC_DATA(MT8173_TEMP_AUXADC_CHANNEL),
> +			mt->thermal_base + TEMP_ADCVOLTADDR);
> +
> +	/* read valid & voltage are at the same register */
> +	writel(0x0, mt->thermal_base + TEMP_RDCTRL);
> +
> +	/* indicate where the valid bit is */
> +	writel(TEMP_ADCVALIDMASK_VALID_HIGH | TEMP_ADCVALIDMASK_VALID_POS(12),
> +			mt->thermal_base + TEMP_ADCVALIDMASK);
> +
> +	/* no shift */
> +	writel(0x0, mt->thermal_base + TEMP_ADCVOLTAGESHIFT);
> +
> +	/* enable auxadc mux write transaction */
> +	writel(TEMP_ADCWRITECTRL_ADC_MUX_WRITE,
> +			mt->thermal_base + TEMP_ADCWRITECTRL);
> +
> +	for (i = 0; i < cfg->num_sensors; i++)
> +		writel(sensor_mux_values[cfg->sensors[i]],
> +				mt->thermal_base + sensing_points[i].adcpnp);
> +
> +	writel((1 << cfg->num_sensors) - 1, mt->thermal_base + TEMP_MONCTL0);
> +
> +	writel(TEMP_ADCWRITECTRL_ADC_PNP_WRITE | TEMP_ADCWRITECTRL_ADC_MUX_WRITE,
> +			mt->thermal_base + TEMP_ADCWRITECTRL);
> +
> +	mtk_thermal_put_bank(bank);
> +}
> +
> +static u64 of_get_phys_base(struct device_node *np)
> +{
> +	u64 size64;
> +	const __be32 *regaddr_p;
> +
> +	regaddr_p = of_get_address(np, 0, &size64, NULL);
> +	if (!regaddr_p)
> +		return OF_BAD_ADDR;
> +
> +	return of_translate_address(np, regaddr_p);
> +}
> +
> +static int mtk_thermal_probe(struct platform_device *pdev)
> +{
> +	int ret, i;
> +	struct device_node *auxadc, *apmixedsys, *np = pdev->dev.of_node;
> +	struct mtk_thermal *mt;
> +	struct resource *res;
> +	u64 auxadc_phys_base, apmixed_phys_base;
> +
> +	mt = devm_kzalloc(&pdev->dev, sizeof(*mt), GFP_KERNEL);
> +	if (!mt)
> +		return -ENOMEM;
> +
> +	mt->clk_peri_therm = devm_clk_get(&pdev->dev, "therm");
> +	if (IS_ERR(mt->clk_peri_therm))
> +		return PTR_ERR(mt->clk_peri_therm);
> +
> +	mt->clk_auxadc = devm_clk_get(&pdev->dev, "auxadc");
> +	if (IS_ERR(mt->clk_auxadc))
> +		return PTR_ERR(mt->clk_auxadc);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	mt->thermal_base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(mt->thermal_base))
> +		return PTR_ERR(mt->thermal_base);
> +
> +	mutex_init(&mt->lock);
> +
> +	mt->dev = &pdev->dev;
> +
> +	auxadc = of_parse_phandle(np, "mediatek,auxadc", 0);
of_put?
> +	if (!auxadc) {
> +		dev_err(&pdev->dev, "missing auxadc node\n");
> +		return -ENODEV;
> +	}
> +
> +	auxadc_phys_base = of_get_phys_base(auxadc);
> +	if (auxadc_phys_base == OF_BAD_ADDR) {
> +		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
> +		return -EINVAL;
> +	}
> +
> +	apmixedsys = of_parse_phandle(np, "mediatek,apmixedsys", 0);
> +	if (!apmixedsys) {
> +		dev_err(&pdev->dev, "missing apmixedsys node\n");
> +		return -ENODEV;
> +	}
> +
> +	apmixed_phys_base = of_get_phys_base(apmixedsys);
> +	if (apmixed_phys_base == OF_BAD_ADDR) {
> +		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_prepare_enable(mt->clk_auxadc);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't enable auxadc clk: %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = device_reset(&pdev->dev);
> +	if (ret)
> +		goto err_disable_clk_auxadc;
> +
> +	ret = clk_prepare_enable(mt->clk_peri_therm);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't enable peri clk: %d\n", ret);
> +		goto err_disable_clk_auxadc;
> +	}
> +
> +	/*
> +	 * These calibration values should finally be provided by the
> +	 * firmware or fuses. For now use default values.
> +	 */
> +	mt->calib_slope = -123;
> +	mt->calib_offset = 465124;

I would still prefer that this driver would not have these hardcoded
values. Specially considering the fact that we could map it in DT for
instance. What is the impact of using this? Does it work across all chip
distribution?

Should we wait until you have the code to read the fuses before merging
this?

> +
> +	for (i = 0; i < MT8173_NUM_ZONES; i++)
> +		mtk_thermal_init_bank(mt, i, apmixed_phys_base, auxadc_phys_base);
> +
> +	platform_set_drvdata(pdev, mt);
> +
> +	for (i = 0; i < MT8173_NUM_ZONES; i++) {
> +		struct mtk_thermal_bank *bank = &mt->banks[i];
> +
> +		bank->tzd = thermal_zone_of_sensor_register(&pdev->dev, i, bank,
> +				&mtk_thermal_ops);

You need to error handle this.

> +	}
> +
> +	return 0;
> +
> +err_disable_clk_auxadc:
> +	clk_disable_unprepare(mt->clk_auxadc);
> +
> +	return ret;
> +}
> +
> +static int mtk_thermal_remove(struct platform_device *pdev)
> +{
> +	struct mtk_thermal *mt = platform_get_drvdata(pdev);
> +	int i;
> +
> +	for (i = 0; i < MT8173_NUM_ZONES; i++) {
> +		struct mtk_thermal_bank *bank = &mt->banks[i];
> +
> +		thermal_zone_of_sensor_unregister(&pdev->dev, bank->tzd);
> +	}
> +
> +	clk_disable_unprepare(mt->clk_peri_therm);
> +	clk_disable_unprepare(mt->clk_auxadc);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mtk_thermal_of_match[] = {
> +	{
> +		.compatible = "mediatek,mt8173-thermal",
> +	}, {
> +	},
> +};
> +
> +static struct platform_driver mtk_thermal_driver = {
> +	.probe = mtk_thermal_probe,
> +	.remove = mtk_thermal_remove,
> +	.driver = {
> +		.name = THERMAL_NAME,
> +		.of_match_table = mtk_thermal_of_match,
> +	},
> +};
> +
> +module_platform_driver(mtk_thermal_driver);
> +
> +MODULE_AUTHOR("Sascha Hauer <[e-mail]");
> +MODULE_DESCRIPTION("Mediatek thermal driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.5.1
> 
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Sascha Hauer Sept. 30, 2015, 6:13 a.m. UTC | #3

Hi Eduardo,

On Tue, Sep 29, 2015 at 04:04:40PM -0700, Eduardo Valentin wrote:
> On Wed, Sep 23, 2015 at 03:37:42PM +0200, Sascha Hauer wrote:
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> 
> You dont seam to be using this header. Can you please clean up to have
> only the headers you need?

Ok, did that.

> > +	struct mtk_thermal *mt = bank->mt;
> > +	int temp, i, max;
> > +	u32 raw;
> > +
> > +	temp = max = INT_MIN;
> > +
> > +	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
> > +		raw = readl(mt->thermal_base + sensing_points[i].msr);
> > +
> > +		temp = raw_to_mcelsius(mt, raw);
> > +
> > +		/*
> > +		 * The first read of a sensor often contains very high bogus
> > +		 * temperature value. Filter these out so that the system does
> > +		 * not immediately shut down.
> > +		 */
> > +		if (temp > 200000)
> 
> Ok... How about after the first read?  is > 200000 a valid (supported) value range?

No, temperatures over 200°C are not supported for this SoC.

> > +
> > +	mt->dev = &pdev->dev;
> > +
> > +	auxadc = of_parse_phandle(np, "mediatek,auxadc", 0);
> of_put?

added

> > +	if (!auxadc) {
> > +		dev_err(&pdev->dev, "missing auxadc node\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	auxadc_phys_base = of_get_phys_base(auxadc);
> > +	if (auxadc_phys_base == OF_BAD_ADDR) {
> > +		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	apmixedsys = of_parse_phandle(np, "mediatek,apmixedsys", 0);
> > +	if (!apmixedsys) {
> > +		dev_err(&pdev->dev, "missing apmixedsys node\n");
> > +		return -ENODEV;
> > +	}

For this one aswell.

> > +	/*
> > +	 * These calibration values should finally be provided by the
> > +	 * firmware or fuses. For now use default values.
> > +	 */
> > +	mt->calib_slope = -123;
> > +	mt->calib_offset = 465124;
> 
> I would still prefer that this driver would not have these hardcoded
> values. Specially considering the fact that we could map it in DT for
> instance. What is the impact of using this? Does it work across all chip
> distribution?

I think yes, but not that accurate.

> 
> Should we wait until you have the code to read the fuses before merging
> this?

I'd say we should merge this. It makes the life easier for the guys
writing the cpufreq driver. Adding a dependency on a not yet written
driver IMO only adds unnecessary delays.

> 
> > +
> > +	for (i = 0; i < MT8173_NUM_ZONES; i++)
> > +		mtk_thermal_init_bank(mt, i, apmixed_phys_base, auxadc_phys_base);
> > +
> > +	platform_set_drvdata(pdev, mt);
> > +
> > +	for (i = 0; i < MT8173_NUM_ZONES; i++) {
> > +		struct mtk_thermal_bank *bank = &mt->banks[i];
> > +
> > +		bank->tzd = thermal_zone_of_sensor_register(&pdev->dev, i, bank,
> > +				&mtk_thermal_ops);
> 
> You need to error handle this.

Errors here are pretty much expected. This is due to the behaviour of
thermal_zone_of_sensor_register which errors out when no user for a
sensor is found. Normally I would expect that I can register a sensor
regardless if it is used or not, but that's not how
thermal_zone_of_sensor_register is written.

I could catch -EPROBE_DEFER here, but currently I see no case where this
can actually be returned from thermal_zone_of_sensor_register.

What I can and should do though is to call
thermal_zone_of_sensor_unregister only for sensors that are successfully
registered.

Sascha

Sascha Hauer Sept. 30, 2015, 6:14 a.m. UTC | #4

Hi Vladimir,

On Wed, Sep 23, 2015 at 09:31:12PM +0300, Vladimir Zapolskiy wrote:
> Hi Sascha,
> 
> in case of OF_DYNAMIC enabled of_parse_phandle() requires of_node_put(),
> which is fine to place right here.
> 
> > +	if (auxadc_phys_base == OF_BAD_ADDR) {
> > +		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
> > +		return -EINVAL;
> > +	}
> > +
> 
> [snip]
> 
> > +
> > +	/*
> > +	 * These calibration values should finally be provided by the
> > +	 * firmware or fuses. For now use default values.
> > +	 */
> > +	mt->calib_slope = -123;
> > +	mt->calib_offset = 465124;
> > +
> > +	for (i = 0; i < MT8173_NUM_ZONES; i++)
> > +		mtk_thermal_init_bank(mt, i, apmixed_phys_base, auxadc_phys_base);
> > +
> > +	platform_set_drvdata(pdev, mt);
> > +
> > +	for (i = 0; i < MT8173_NUM_ZONES; i++) {
> > +		struct mtk_thermal_bank *bank = &mt->banks[i];
> > +
> > +		bank->tzd = thermal_zone_of_sensor_register(&pdev->dev, i, bank,
> > +				&mtk_thermal_ops);
> 
> I would propose to add return value checks here, otherwise there might
> be an oops in mtk_thermal_remove(), if something goes wrong.

Thanks for the input. I'll fix that in the next round.

Sascha

Punit Agrawal Sept. 30, 2015, 9:36 a.m. UTC | #5

Hi Sascha,

Re-posting a comment from v7. Perhaps you missed it...

Sascha Hauer <[e-mail]> writes:

> This adds support for the Mediatek thermal controller found on MT8173
> and likely other SoCs.
> The controller is a bit special. It does not have its own ADC, instead
> it controls the on-SoC AUXADC via AHB bus accesses. For this reason
> we need the physical address of the AUXADC. Also it controls a mux
> using AHB bus accesses, so we need the APMIXEDSYS physical address aswell.
>
> Signed-off-by: Sascha Hauer <[e-mail]>
> Reviewed-by: Daniel Kurtz <[e-mail]>
> ---
>  drivers/thermal/Kconfig       |   8 +
>  drivers/thermal/Makefile      |   1 +
>  drivers/thermal/mtk_thermal.c | 537 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 546 insertions(+)
>  create mode 100644 drivers/thermal/mtk_thermal.c
>
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index 0390044..dadd1eb 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -348,6 +348,14 @@ config INTEL_PCH_THERMAL
>  	  Thermal reporting device will provide temperature reading,
>  	  programmable trip points and other information.
>  
> +config MTK_THERMAL
> +	tristate "Temperature sensor driver for mediatek SoCs"
> +	depends on ARCH_MEDIATEK || COMPILE_TEST
> +	default y
> +	help
> +	  Enable this option if you want to have support for thermal management
> +	  controller present in Mediatek SoCs
> +
>  menu "Texas Instruments thermal drivers"
>  source "drivers/thermal/ti-soc-thermal/Kconfig"
>  endmenu
> diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
> index 26f1608..5f979e7 100644
> --- a/drivers/thermal/Makefile
> +++ b/drivers/thermal/Makefile
> @@ -45,3 +45,4 @@ obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
>  obj-$(CONFIG_ST_THERMAL)	+= st/
>  obj-$(CONFIG_TEGRA_SOCTHERM)	+= tegra_soctherm.o
>  obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
> +obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o
> diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> new file mode 100644
> index 0000000..6be1a6c
> --- /dev/null
> +++ b/drivers/thermal/mtk_thermal.c
> @@ -0,0 +1,537 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: Hanyi Wu <[e-mail]>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/thermal.h>
> +#include <linux/reset.h>
> +#include <linux/time.h>
> +#include <linux/types.h>
> +#include <dt-bindings/thermal/mt8173.h>
> +
> +/* AUXADC Registers */
> +#define AUXADC_CON0_V		0x000
> +#define AUXADC_CON1_V		0x004
> +#define AUXADC_CON1_SET_V	0x008
> +#define AUXADC_CON1_CLR_V	0x00c
> +#define AUXADC_CON2_V		0x010
> +#define AUXADC_DATA(channel)	(0x14 + (channel) * 4)
> +#define AUXADC_MISC_V		0x094
> +
> +#define AUXADC_CON1_CHANNEL(x)	BIT(x)
> +
> +#define APMIXED_SYS_TS_CON1	0x604
> +
> +/* Thermal Controller Registers */
> +#define TEMP_MONCTL0		0x000
> +#define TEMP_MONCTL1		0x004
> +#define TEMP_MONCTL2		0x008
> +#define TEMP_MONIDET0		0x014
> +#define TEMP_MONIDET1		0x018
> +#define TEMP_MSRCTL0		0x038
> +#define TEMP_AHBPOLL		0x040
> +#define TEMP_AHBTO		0x044
> +#define TEMP_ADCPNP0		0x048
> +#define TEMP_ADCPNP1		0x04c
> +#define TEMP_ADCPNP2		0x050
> +#define TEMP_ADCPNP3		0x0b4
> +
> +#define TEMP_ADCMUX		0x054
> +#define TEMP_ADCEN		0x060
> +#define TEMP_PNPMUXADDR		0x064
> +#define TEMP_ADCMUXADDR		0x068
> +#define TEMP_ADCENADDR		0x074
> +#define TEMP_ADCVALIDADDR	0x078
> +#define TEMP_ADCVOLTADDR	0x07c
> +#define TEMP_RDCTRL		0x080
> +#define TEMP_ADCVALIDMASK	0x084
> +#define TEMP_ADCVOLTAGESHIFT	0x088
> +#define TEMP_ADCWRITECTRL	0x08c
> +#define TEMP_MSR0		0x090
> +#define TEMP_MSR1		0x094
> +#define TEMP_MSR2		0x098
> +#define TEMP_MSR3		0x0B8
> +
> +#define TEMP_SPARE0		0x0f0
> +
> +#define PTPCORESEL		0x400
> +
> +#define TEMP_MONCTL1_PERIOD_UNIT(x)	((x) & 0x3ff)
> +
> +#define TEMP_MONCTL2_FILTER_INTERVAL(x)	(((x) & 0x3ff)) << 16
> +#define TEMP_MONCTL2_SENSOR_INTERVAL(x)	((x) & 0x3ff)
> +
> +#define TEMP_AHBPOLL_ADC_POLL_INTERVAL(x)	(x)
> +
> +#define TEMP_ADCWRITECTRL_ADC_PNP_WRITE		BIT(0)
> +#define TEMP_ADCWRITECTRL_ADC_MUX_WRITE		BIT(1)
> +
> +#define TEMP_ADCVALIDMASK_VALID_HIGH		BIT(5)
> +#define TEMP_ADCVALIDMASK_VALID_POS(bit)	(bit)
> +
> +#define MT8173_TS1	0
> +#define MT8173_TS2	1
> +#define MT8173_TS3	2
> +#define MT8173_TS4	3
> +#define MT8173_TSABB	4
> +
> +/* AUXADC channel 11 is used for the temperature sensors */
> +#define MT8173_TEMP_AUXADC_CHANNEL	11
> +
> +/* The total number of temperature sensors in the MT8173 */
> +#define MT8173_NUM_SENSORS		5
> +
> +/* The number of banks in the MT8173 */
> +#define MT8173_NUM_ZONES		4
> +
> +/* The number of sensing points per bank */
> +#define MT8173_NUM_SENSORS_PER_ZONE	4
> +
> +#define THERMAL_NAME    "mtk-thermal"
> +
> +struct mtk_thermal;
> +
> +struct mtk_thermal_bank {
> +	struct mtk_thermal *mt;
> +	struct thermal_zone_device *tzd;
> +	int id;
> +};
> +
> +struct mtk_thermal {
> +	struct device *dev;
> +	void __iomem *thermal_base;
> +
> +	struct clk *clk_peri_therm;
> +	struct clk *clk_auxadc;
> +
> +	struct mtk_thermal_bank banks[MT8173_NUM_ZONES];
> +
> +	struct mutex lock;
> +
> +	/* Calibration values */
> +	int calib_slope;
> +	int calib_offset;
> +};
> +
> +struct mtk_thermal_bank_cfg {
> +	unsigned int num_sensors;
> +	unsigned int sensors[MT8173_NUM_SENSORS_PER_ZONE];
> +};
> +
> +static const int sensor_mux_values[MT8173_NUM_SENSORS] = { 0, 1, 2, 3, 16 };
> +
> +/*
> + * The MT8173 thermal controller has four banks. Each bank can read up to
> + * four temperature sensors simultaneously. The MT8173 has a total of 5
> + * temperature sensors. We use each bank to measure a certain area of the
> + * SoC. Since TS2 is located centrally in the SoC it is influenced by multiple
> + * areas, hence is used in different banks.
> + */
> +static const struct mtk_thermal_bank_cfg bank_data[] = {
> +	[MT8173_THERMAL_ZONE_CA53] = {
> +		.num_sensors = 2,
> +		.sensors = { MT8173_TS2, MT8173_TS3 },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_CA57] = {
> +		.num_sensors = 2,
> +		.sensors = { MT8173_TS2, MT8173_TS4 },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_GPU] = {
> +		.num_sensors = 3,
> +		.sensors = { MT8173_TS1, MT8173_TS2, MT8173_TSABB },
> +	},
> +
> +	[MT8173_THERMAL_ZONE_CORE] = {
> +		.num_sensors = 1,
> +		.sensors = { MT8173_TS2 },
> +	},
> +};
> +
> +struct mtk_thermal_sense_point {
> +	int msr;
> +	int adcpnp;
> +};
> +
> +static const struct mtk_thermal_sense_point
> +		sensing_points[MT8173_NUM_SENSORS_PER_ZONE] = {
> +	{
> +		.msr = TEMP_MSR0,
> +		.adcpnp = TEMP_ADCPNP0,
> +	}, {
> +		.msr = TEMP_MSR1,
> +		.adcpnp = TEMP_ADCPNP1,
> +	}, {
> +		.msr = TEMP_MSR2,
> +		.adcpnp = TEMP_ADCPNP2,
> +	}, {
> +		.msr = TEMP_MSR3,
> +		.adcpnp = TEMP_ADCPNP3,
> +	},
> +};
> +
> +/**
> + * raw_to_mcelsius - convert a raw ADC value to mcelsius
> + * @mt:		The thermal controller
> + * @raw:	raw ADC value
> + *
> + * This converts the raw ADC value to mcelsius using the SoC specific
> + * calibration constants
> + */
> +static int raw_to_mcelsius(struct mtk_thermal *mt, u32 raw)
> +{
> +	return mt->calib_offset + mt->calib_slope * (raw & 0xfff);
> +}
> +
> +/**
> + * mtk_thermal_get_bank - get bank
> + * @bank:	The bank
> + *
> + * The bank registers are banked, we have to select a bank in the
> + * PTPCORESEL register to access it.
> + */
> +static void mtk_thermal_get_bank(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +	u32 val;
> +
> +	mutex_lock(&mt->lock);
> +
> +	val = readl(mt->thermal_base + PTPCORESEL);
> +	val &= ~0xf;
> +	val |= bank->id;
> +	writel(val, mt->thermal_base + PTPCORESEL);
> +}
> +
> +/**
> + * mtk_thermal_put_bank - release bank
> + * @bank:	The bank
> + *
> + * release a bank previously taken with mtk_thermal_get_bank,
> + */
> +static void mtk_thermal_put_bank(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +
> +	mutex_unlock(&mt->lock);
> +}
> +
> +/**
> + * mtk_thermal_bank_temperature - get the temperature of a bank
> + * @bank:	The bank
> + *
> + * The temperature of a bank is considered the maximum temperature of
> + * the sensors associated to the bank.
> + */
> +static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
> +{
> +	struct mtk_thermal *mt = bank->mt;
> +	int temp, i, max;
> +	u32 raw;
> +
> +	temp = max = INT_MIN;
> +
> +	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
> +		raw = readl(mt->thermal_base + sensing_points[i].msr);
> +
> +		temp = raw_to_mcelsius(mt, raw);
> +
> +		/*
> +		 * The first read of a sensor often contains very high bogus
> +		 * temperature value. Filter these out so that the system does
> +		 * not immediately shut down.
> +		 */
> +		if (temp > 200000)
> +			temp = 0;
> +

If the bogus value is only the first time the sensor is read, instead of
filtering here, you could call mtk_thermal_bank_temperature at probe
time when you are initialising the banks and ignore the returned value.

Thanks,
Punit

> +		if (temp > max)
> +			max = temp;
> +	}
> +
> +	return max;
> +}
> +

[...]

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Sascha Hauer Sept. 30, 2015, 10:37 a.m. UTC | #6

Hi Punit,

On Wed, Sep 30, 2015 at 10:36:14AM +0100, Punit Agrawal wrote:
> Hi Sascha,
> 
> Re-posting a comment from v7. Perhaps you missed it...

Uh, sorry. In fact I didn't miss it and I thought I have answered it.
Appearantly I haven't.

> > +	struct mtk_thermal *mt = bank->mt;
> > +	int temp, i, max;
> > +	u32 raw;
> > +
> > +	temp = max = INT_MIN;
> > +
> > +	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
> > +		raw = readl(mt->thermal_base + sensing_points[i].msr);
> > +
> > +		temp = raw_to_mcelsius(mt, raw);
> > +
> > +		/*
> > +		 * The first read of a sensor often contains very high bogus
> > +		 * temperature value. Filter these out so that the system does
> > +		 * not immediately shut down.
> > +		 */
> > +		if (temp > 200000)
> > +			temp = 0;
> > +
> 
> If the bogus value is only the first time the sensor is read, instead of
> filtering here, you could call mtk_thermal_bank_temperature at probe
> time when you are initialising the banks and ignore the returned value.

It seems that after initialization the hardware needs some time to
settle before correct values can be read. Doing what you suggest would
mean we have to delay the boot by several 100ms. I'd rather not do that.

Sascha

Punit Agrawal Sept. 30, 2015, 11:07 a.m. UTC | #7

Sascha Hauer <[e-mail]> writes:

> Hi Punit,
>
> On Wed, Sep 30, 2015 at 10:36:14AM +0100, Punit Agrawal wrote:
>> Hi Sascha,
>> 
>> Re-posting a comment from v7. Perhaps you missed it...
>
> Uh, sorry. In fact I didn't miss it and I thought I have answered it.
> Appearantly I haven't.
>
>> > +	struct mtk_thermal *mt = bank->mt;
>> > +	int temp, i, max;
>> > +	u32 raw;
>> > +
>> > +	temp = max = INT_MIN;
>> > +
>> > +	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
>> > +		raw = readl(mt->thermal_base + sensing_points[i].msr);
>> > +
>> > +		temp = raw_to_mcelsius(mt, raw);
>> > +
>> > +		/*
>> > +		 * The first read of a sensor often contains very high bogus
>> > +		 * temperature value. Filter these out so that the system does
>> > +		 * not immediately shut down.
>> > +		 */
>> > +		if (temp > 200000)
>> > +			temp = 0;
>> > +
>> 
>> If the bogus value is only the first time the sensor is read, instead of
>> filtering here, you could call mtk_thermal_bank_temperature at probe
>> time when you are initialising the banks and ignore the returned value.
>
> It seems that after initialization the hardware needs some time to
> settle before correct values can be read. Doing what you suggest would
> mean we have to delay the boot by several 100ms. I'd rather not do that.

Fair enough. Thanks for clarifying.

>
> Sascha
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Patch

diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
index 0390044..dadd1eb 100644
--- a/drivers/thermal/Kconfig
+++ b/drivers/thermal/Kconfig
@@ -348,6 +348,14 @@  config INTEL_PCH_THERMAL
 	  Thermal reporting device will provide temperature reading,
 	  programmable trip points and other information.
 
+config MTK_THERMAL
+	tristate "Temperature sensor driver for mediatek SoCs"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	default y
+	help
+	  Enable this option if you want to have support for thermal management
+	  controller present in Mediatek SoCs
+
 menu "Texas Instruments thermal drivers"
 source "drivers/thermal/ti-soc-thermal/Kconfig"
 endmenu
diff --git a/drivers/thermal/Makefile b/drivers/thermal/Makefile
index 26f1608..5f979e7 100644
--- a/drivers/thermal/Makefile
+++ b/drivers/thermal/Makefile
@@ -45,3 +45,4 @@  obj-$(CONFIG_INTEL_PCH_THERMAL)	+= intel_pch_thermal.o
 obj-$(CONFIG_ST_THERMAL)	+= st/
 obj-$(CONFIG_TEGRA_SOCTHERM)	+= tegra_soctherm.o
 obj-$(CONFIG_HISI_THERMAL)     += hisi_thermal.o
+obj-$(CONFIG_MTK_THERMAL)	+= mtk_thermal.o
diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
new file mode 100644
index 0000000..6be1a6c
--- /dev/null
+++ b/drivers/thermal/mtk_thermal.c
@@ -0,0 +1,537 @@ 
+/*
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: Hanyi Wu <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+#include <linux/reset.h>
+#include <linux/time.h>
+#include <linux/types.h>
+#include <dt-bindings/thermal/mt8173.h>
+
+/* AUXADC Registers */
+#define AUXADC_CON0_V		0x000
+#define AUXADC_CON1_V		0x004
+#define AUXADC_CON1_SET_V	0x008
+#define AUXADC_CON1_CLR_V	0x00c
+#define AUXADC_CON2_V		0x010
+#define AUXADC_DATA(channel)	(0x14 + (channel) * 4)
+#define AUXADC_MISC_V		0x094
+
+#define AUXADC_CON1_CHANNEL(x)	BIT(x)
+
+#define APMIXED_SYS_TS_CON1	0x604
+
+/* Thermal Controller Registers */
+#define TEMP_MONCTL0		0x000
+#define TEMP_MONCTL1		0x004
+#define TEMP_MONCTL2		0x008
+#define TEMP_MONIDET0		0x014
+#define TEMP_MONIDET1		0x018
+#define TEMP_MSRCTL0		0x038
+#define TEMP_AHBPOLL		0x040
+#define TEMP_AHBTO		0x044
+#define TEMP_ADCPNP0		0x048
+#define TEMP_ADCPNP1		0x04c
+#define TEMP_ADCPNP2		0x050
+#define TEMP_ADCPNP3		0x0b4
+
+#define TEMP_ADCMUX		0x054
+#define TEMP_ADCEN		0x060
+#define TEMP_PNPMUXADDR		0x064
+#define TEMP_ADCMUXADDR		0x068
+#define TEMP_ADCENADDR		0x074
+#define TEMP_ADCVALIDADDR	0x078
+#define TEMP_ADCVOLTADDR	0x07c
+#define TEMP_RDCTRL		0x080
+#define TEMP_ADCVALIDMASK	0x084
+#define TEMP_ADCVOLTAGESHIFT	0x088
+#define TEMP_ADCWRITECTRL	0x08c
+#define TEMP_MSR0		0x090
+#define TEMP_MSR1		0x094
+#define TEMP_MSR2		0x098
+#define TEMP_MSR3		0x0B8
+
+#define TEMP_SPARE0		0x0f0
+
+#define PTPCORESEL		0x400
+
+#define TEMP_MONCTL1_PERIOD_UNIT(x)	((x) & 0x3ff)
+
+#define TEMP_MONCTL2_FILTER_INTERVAL(x)	(((x) & 0x3ff)) << 16
+#define TEMP_MONCTL2_SENSOR_INTERVAL(x)	((x) & 0x3ff)
+
+#define TEMP_AHBPOLL_ADC_POLL_INTERVAL(x)	(x)
+
+#define TEMP_ADCWRITECTRL_ADC_PNP_WRITE		BIT(0)
+#define TEMP_ADCWRITECTRL_ADC_MUX_WRITE		BIT(1)
+
+#define TEMP_ADCVALIDMASK_VALID_HIGH		BIT(5)
+#define TEMP_ADCVALIDMASK_VALID_POS(bit)	(bit)
+
+#define MT8173_TS1	0
+#define MT8173_TS2	1
+#define MT8173_TS3	2
+#define MT8173_TS4	3
+#define MT8173_TSABB	4
+
+/* AUXADC channel 11 is used for the temperature sensors */
+#define MT8173_TEMP_AUXADC_CHANNEL	11
+
+/* The total number of temperature sensors in the MT8173 */
+#define MT8173_NUM_SENSORS		5
+
+/* The number of banks in the MT8173 */
+#define MT8173_NUM_ZONES		4
+
+/* The number of sensing points per bank */
+#define MT8173_NUM_SENSORS_PER_ZONE	4
+
+#define THERMAL_NAME    "mtk-thermal"
+
+struct mtk_thermal;
+
+struct mtk_thermal_bank {
+	struct mtk_thermal *mt;
+	struct thermal_zone_device *tzd;
+	int id;
+};
+
+struct mtk_thermal {
+	struct device *dev;
+	void __iomem *thermal_base;
+
+	struct clk *clk_peri_therm;
+	struct clk *clk_auxadc;
+
+	struct mtk_thermal_bank banks[MT8173_NUM_ZONES];
+
+	struct mutex lock;
+
+	/* Calibration values */
+	int calib_slope;
+	int calib_offset;
+};
+
+struct mtk_thermal_bank_cfg {
+	unsigned int num_sensors;
+	unsigned int sensors[MT8173_NUM_SENSORS_PER_ZONE];
+};
+
+static const int sensor_mux_values[MT8173_NUM_SENSORS] = { 0, 1, 2, 3, 16 };
+
+/*
+ * The MT8173 thermal controller has four banks. Each bank can read up to
+ * four temperature sensors simultaneously. The MT8173 has a total of 5
+ * temperature sensors. We use each bank to measure a certain area of the
+ * SoC. Since TS2 is located centrally in the SoC it is influenced by multiple
+ * areas, hence is used in different banks.
+ */
+static const struct mtk_thermal_bank_cfg bank_data[] = {
+	[MT8173_THERMAL_ZONE_CA53] = {
+		.num_sensors = 2,
+		.sensors = { MT8173_TS2, MT8173_TS3 },
+	},
+
+	[MT8173_THERMAL_ZONE_CA57] = {
+		.num_sensors = 2,
+		.sensors = { MT8173_TS2, MT8173_TS4 },
+	},
+
+	[MT8173_THERMAL_ZONE_GPU] = {
+		.num_sensors = 3,
+		.sensors = { MT8173_TS1, MT8173_TS2, MT8173_TSABB },
+	},
+
+	[MT8173_THERMAL_ZONE_CORE] = {
+		.num_sensors = 1,
+		.sensors = { MT8173_TS2 },
+	},
+};
+
+struct mtk_thermal_sense_point {
+	int msr;
+	int adcpnp;
+};
+
+static const struct mtk_thermal_sense_point
+		sensing_points[MT8173_NUM_SENSORS_PER_ZONE] = {
+	{
+		.msr = TEMP_MSR0,
+		.adcpnp = TEMP_ADCPNP0,
+	}, {
+		.msr = TEMP_MSR1,
+		.adcpnp = TEMP_ADCPNP1,
+	}, {
+		.msr = TEMP_MSR2,
+		.adcpnp = TEMP_ADCPNP2,
+	}, {
+		.msr = TEMP_MSR3,
+		.adcpnp = TEMP_ADCPNP3,
+	},
+};
+
+/**
+ * raw_to_mcelsius - convert a raw ADC value to mcelsius
+ * @mt:		The thermal controller
+ * @raw:	raw ADC value
+ *
+ * This converts the raw ADC value to mcelsius using the SoC specific
+ * calibration constants
+ */
+static int raw_to_mcelsius(struct mtk_thermal *mt, u32 raw)
+{
+	return mt->calib_offset + mt->calib_slope * (raw & 0xfff);
+}
+
+/**
+ * mtk_thermal_get_bank - get bank
+ * @bank:	The bank
+ *
+ * The bank registers are banked, we have to select a bank in the
+ * PTPCORESEL register to access it.
+ */
+static void mtk_thermal_get_bank(struct mtk_thermal_bank *bank)
+{
+	struct mtk_thermal *mt = bank->mt;
+	u32 val;
+
+	mutex_lock(&mt->lock);
+
+	val = readl(mt->thermal_base + PTPCORESEL);
+	val &= ~0xf;
+	val |= bank->id;
+	writel(val, mt->thermal_base + PTPCORESEL);
+}
+
+/**
+ * mtk_thermal_put_bank - release bank
+ * @bank:	The bank
+ *
+ * release a bank previously taken with mtk_thermal_get_bank,
+ */
+static void mtk_thermal_put_bank(struct mtk_thermal_bank *bank)
+{
+	struct mtk_thermal *mt = bank->mt;
+
+	mutex_unlock(&mt->lock);
+}
+
+/**
+ * mtk_thermal_bank_temperature - get the temperature of a bank
+ * @bank:	The bank
+ *
+ * The temperature of a bank is considered the maximum temperature of
+ * the sensors associated to the bank.
+ */
+static int mtk_thermal_bank_temperature(struct mtk_thermal_bank *bank)
+{
+	struct mtk_thermal *mt = bank->mt;
+	int temp, i, max;
+	u32 raw;
+
+	temp = max = INT_MIN;
+
+	for (i = 0; i < bank_data[bank->id].num_sensors; i++) {
+		raw = readl(mt->thermal_base + sensing_points[i].msr);
+
+		temp = raw_to_mcelsius(mt, raw);
+
+		/*
+		 * The first read of a sensor often contains very high bogus
+		 * temperature value. Filter these out so that the system does
+		 * not immediately shut down.
+		 */
+		if (temp > 200000)
+			temp = 0;
+
+		if (temp > max)
+			max = temp;
+	}
+
+	return max;
+}
+
+static int mtk_read_temp(void *data, int *temp)
+{
+	struct mtk_thermal_bank *bank = data;
+
+	mtk_thermal_get_bank(bank);
+
+	*temp = mtk_thermal_bank_temperature(bank);
+
+	mtk_thermal_put_bank(bank);
+
+	return 0;
+}
+
+static const struct thermal_zone_of_device_ops mtk_thermal_ops = {
+	.get_temp = mtk_read_temp,
+};
+
+static void mtk_thermal_init_bank(struct mtk_thermal *mt, int num,
+		u32 apmixed_phys_base, u32 auxadc_phys_base)
+{
+	struct mtk_thermal_bank *bank = &mt->banks[num];
+	const struct mtk_thermal_bank_cfg *cfg = &bank_data[num];
+	int i;
+
+	bank->id = num;
+	bank->mt = mt;
+
+	mtk_thermal_get_bank(bank);
+
+	/* bus clock 66M counting unit is 12 * 15.15ns * 256 = 46.540us */
+	writel(TEMP_MONCTL1_PERIOD_UNIT(12), mt->thermal_base + TEMP_MONCTL1);
+
+	/*
+	 * filt interval is 1 * 46.540us = 46.54us,
+	 * sen interval is 429 * 46.540us = 19.96ms
+	 */
+	writel(TEMP_MONCTL2_FILTER_INTERVAL(1) |
+			TEMP_MONCTL2_SENSOR_INTERVAL(429),
+			mt->thermal_base + TEMP_MONCTL2);
+
+	/* poll is set to 10u */
+	writel(TEMP_AHBPOLL_ADC_POLL_INTERVAL(768),
+			mt->thermal_base + TEMP_AHBPOLL);
+
+	/* temperature sampling control, 1 sample */
+	writel(0x00000000, mt->thermal_base + TEMP_MSRCTL0);
+
+	/* exceed this polling time, IRQ would be inserted */
+	writel(0xffffffff, mt->thermal_base + TEMP_AHBTO);
+
+	/* number of interrupts per event, 1 is enough */
+	writel(0x0, mt->thermal_base + TEMP_MONIDET0);
+	writel(0x0, mt->thermal_base + TEMP_MONIDET1);
+
+	/*
+	 * The MT8173 thermal controller does not have its own ADC. Instead it
+	 * uses AHB bus accesses to control the AUXADC. To do this the thermal
+	 * controller has to be programmed with the physical addresses of the
+	 * AUXADC registers and with the various bit positions in the AUXADC.
+	 * Also the thermal controller controls a mux in the APMIXEDSYS register
+	 * space.
+	 */
+
+	/*
+	 * this value will be stored to TEMP_PNPMUXADDR (TEMP_SPARE0)
+	 * automatically by hw
+	 */
+	writel(BIT(MT8173_TEMP_AUXADC_CHANNEL), mt->thermal_base + TEMP_ADCMUX);
+
+	/* AHB address for auxadc mux selection */
+	writel(auxadc_phys_base + AUXADC_CON1_CLR_V,
+			mt->thermal_base + TEMP_ADCMUXADDR);
+
+	/* AHB address for pnp sensor mux selection */
+	writel(apmixed_phys_base + APMIXED_SYS_TS_CON1,
+			mt->thermal_base + TEMP_PNPMUXADDR);
+
+	/* AHB value for auxadc enable */
+	writel(BIT(MT8173_TEMP_AUXADC_CHANNEL), mt->thermal_base + TEMP_ADCEN);
+
+	/* AHB address for auxadc enable (channel 0 immediate mode selected) */
+	writel(auxadc_phys_base + AUXADC_CON1_SET_V,
+			mt->thermal_base + TEMP_ADCENADDR);
+
+	/* AHB address for auxadc valid bit */
+	writel(auxadc_phys_base + AUXADC_DATA(MT8173_TEMP_AUXADC_CHANNEL),
+			mt->thermal_base + TEMP_ADCVALIDADDR);
+
+	/* AHB address for auxadc voltage output */
+	writel(auxadc_phys_base + AUXADC_DATA(MT8173_TEMP_AUXADC_CHANNEL),
+			mt->thermal_base + TEMP_ADCVOLTADDR);
+
+	/* read valid & voltage are at the same register */
+	writel(0x0, mt->thermal_base + TEMP_RDCTRL);
+
+	/* indicate where the valid bit is */
+	writel(TEMP_ADCVALIDMASK_VALID_HIGH | TEMP_ADCVALIDMASK_VALID_POS(12),
+			mt->thermal_base + TEMP_ADCVALIDMASK);
+
+	/* no shift */
+	writel(0x0, mt->thermal_base + TEMP_ADCVOLTAGESHIFT);
+
+	/* enable auxadc mux write transaction */
+	writel(TEMP_ADCWRITECTRL_ADC_MUX_WRITE,
+			mt->thermal_base + TEMP_ADCWRITECTRL);
+
+	for (i = 0; i < cfg->num_sensors; i++)
+		writel(sensor_mux_values[cfg->sensors[i]],
+				mt->thermal_base + sensing_points[i].adcpnp);
+
+	writel((1 << cfg->num_sensors) - 1, mt->thermal_base + TEMP_MONCTL0);
+
+	writel(TEMP_ADCWRITECTRL_ADC_PNP_WRITE | TEMP_ADCWRITECTRL_ADC_MUX_WRITE,
+			mt->thermal_base + TEMP_ADCWRITECTRL);
+
+	mtk_thermal_put_bank(bank);
+}
+
+static u64 of_get_phys_base(struct device_node *np)
+{
+	u64 size64;
+	const __be32 *regaddr_p;
+
+	regaddr_p = of_get_address(np, 0, &size64, NULL);
+	if (!regaddr_p)
+		return OF_BAD_ADDR;
+
+	return of_translate_address(np, regaddr_p);
+}
+
+static int mtk_thermal_probe(struct platform_device *pdev)
+{
+	int ret, i;
+	struct device_node *auxadc, *apmixedsys, *np = pdev->dev.of_node;
+	struct mtk_thermal *mt;
+	struct resource *res;
+	u64 auxadc_phys_base, apmixed_phys_base;
+
+	mt = devm_kzalloc(&pdev->dev, sizeof(*mt), GFP_KERNEL);
+	if (!mt)
+		return -ENOMEM;
+
+	mt->clk_peri_therm = devm_clk_get(&pdev->dev, "therm");
+	if (IS_ERR(mt->clk_peri_therm))
+		return PTR_ERR(mt->clk_peri_therm);
+
+	mt->clk_auxadc = devm_clk_get(&pdev->dev, "auxadc");
+	if (IS_ERR(mt->clk_auxadc))
+		return PTR_ERR(mt->clk_auxadc);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mt->thermal_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(mt->thermal_base))
+		return PTR_ERR(mt->thermal_base);
+
+	mutex_init(&mt->lock);
+
+	mt->dev = &pdev->dev;
+
+	auxadc = of_parse_phandle(np, "mediatek,auxadc", 0);
+	if (!auxadc) {
+		dev_err(&pdev->dev, "missing auxadc node\n");
+		return -ENODEV;
+	}
+
+	auxadc_phys_base = of_get_phys_base(auxadc);
+	if (auxadc_phys_base == OF_BAD_ADDR) {
+		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
+		return -EINVAL;
+	}
+
+	apmixedsys = of_parse_phandle(np, "mediatek,apmixedsys", 0);
+	if (!apmixedsys) {
+		dev_err(&pdev->dev, "missing apmixedsys node\n");
+		return -ENODEV;
+	}
+
+	apmixed_phys_base = of_get_phys_base(apmixedsys);
+	if (apmixed_phys_base == OF_BAD_ADDR) {
+		dev_err(&pdev->dev, "Can't get auxadc phys address\n");
+		return -EINVAL;
+	}
+
+	ret = clk_prepare_enable(mt->clk_auxadc);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't enable auxadc clk: %d\n", ret);
+		return ret;
+	}
+
+	ret = device_reset(&pdev->dev);
+	if (ret)
+		goto err_disable_clk_auxadc;
+
+	ret = clk_prepare_enable(mt->clk_peri_therm);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't enable peri clk: %d\n", ret);
+		goto err_disable_clk_auxadc;
+	}
+
+	/*
+	 * These calibration values should finally be provided by the
+	 * firmware or fuses. For now use default values.
+	 */
+	mt->calib_slope = -123;
+	mt->calib_offset = 465124;
+
+	for (i = 0; i < MT8173_NUM_ZONES; i++)
+		mtk_thermal_init_bank(mt, i, apmixed_phys_base, auxadc_phys_base);
+
+	platform_set_drvdata(pdev, mt);
+
+	for (i = 0; i < MT8173_NUM_ZONES; i++) {
+		struct mtk_thermal_bank *bank = &mt->banks[i];
+
+		bank->tzd = thermal_zone_of_sensor_register(&pdev->dev, i, bank,
+				&mtk_thermal_ops);
+	}
+
+	return 0;
+
+err_disable_clk_auxadc:
+	clk_disable_unprepare(mt->clk_auxadc);
+
+	return ret;
+}
+
+static int mtk_thermal_remove(struct platform_device *pdev)
+{
+	struct mtk_thermal *mt = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < MT8173_NUM_ZONES; i++) {
+		struct mtk_thermal_bank *bank = &mt->banks[i];
+
+		thermal_zone_of_sensor_unregister(&pdev->dev, bank->tzd);
+	}
+
+	clk_disable_unprepare(mt->clk_peri_therm);
+	clk_disable_unprepare(mt->clk_auxadc);
+
+	return 0;
+}
+
+static const struct of_device_id mtk_thermal_of_match[] = {
+	{
+		.compatible = "mediatek,mt8173-thermal",
+	}, {
+	},
+};
+
+static struct platform_driver mtk_thermal_driver = {
+	.probe = mtk_thermal_probe,
+	.remove = mtk_thermal_remove,
+	.driver = {
+		.name = THERMAL_NAME,
+		.of_match_table = mtk_thermal_of_match,
+	},
+};
+
+module_platform_driver(mtk_thermal_driver);
+
+MODULE_AUTHOR("Sascha Hauer <[e-mail]");
+MODULE_DESCRIPTION("Mediatek thermal driver");
+MODULE_LICENSE("GPL v2");