diff mbox series

[v6,2/2] hwmon: pmbus: Add ltc4286 driver

Message ID 20231121050757.2108786-3-Delphine_CC_Chiu@Wiwynn.com (mailing list archive)
State Superseded
Headers show
Series LTC4286 and LTC4287 driver support | expand

Commit Message

Delphine CC Chiu Nov. 21, 2023, 5:07 a.m. UTC
Add a driver to support ltc4286 chip

Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
---
Changelog:
  v6 - Check VRANGE_SELECT before driver loading
  v5 - Check the overflow when reading rsense
     - Set default rsense value
  v4 - Add empty line before "config SENSORS_LTC4286" in Kconfig
     - Add ltc4286 to Documentation/hwmon/index.rst
     - Revise comment typo
     - Use devm_kmemdup instead of memcpy
     - Check MBR value before writting into
  v3 - Use dev_err_probe() instead of dev_err()
     - The VRANGE_SELECT bit only be written if it actually changed
     - Avoid the info pointer being overwritten
     - Check the MBR value range to avoid overflow
     - Revise ltc4286.rst to corrcet description
  v2 - Revise Linear Technologies LTC4286 to
       Analog Devices LTC4286 in Kconfig
     - Add more description for this driver in Kconfig
     - Add some comments for MBR setting in ltc4286.c
     - Add ltc4286.rst
---
 Documentation/hwmon/index.rst   |   1 +
 Documentation/hwmon/ltc4286.rst |  95 +++++++++++++++++
 drivers/hwmon/pmbus/Kconfig     |  10 ++
 drivers/hwmon/pmbus/Makefile    |   1 +
 drivers/hwmon/pmbus/ltc4286.c   | 183 ++++++++++++++++++++++++++++++++
 5 files changed, 290 insertions(+)
 create mode 100644 Documentation/hwmon/ltc4286.rst
 create mode 100644 drivers/hwmon/pmbus/ltc4286.c

Comments

Guenter Roeck Nov. 21, 2023, 4:13 p.m. UTC | #1
On 11/20/23 21:07, Delphine CC Chiu wrote:
> Add a driver to support ltc4286 chip
> 
> Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> ---
> Changelog:
>    v6 - Check VRANGE_SELECT before driver loading
>    v5 - Check the overflow when reading rsense
>       - Set default rsense value
>    v4 - Add empty line before "config SENSORS_LTC4286" in Kconfig
>       - Add ltc4286 to Documentation/hwmon/index.rst
>       - Revise comment typo
>       - Use devm_kmemdup instead of memcpy
>       - Check MBR value before writting into
>    v3 - Use dev_err_probe() instead of dev_err()
>       - The VRANGE_SELECT bit only be written if it actually changed
>       - Avoid the info pointer being overwritten
>       - Check the MBR value range to avoid overflow
>       - Revise ltc4286.rst to corrcet description
>    v2 - Revise Linear Technologies LTC4286 to
>         Analog Devices LTC4286 in Kconfig
>       - Add more description for this driver in Kconfig
>       - Add some comments for MBR setting in ltc4286.c
>       - Add ltc4286.rst
> ---
>   Documentation/hwmon/index.rst   |   1 +
>   Documentation/hwmon/ltc4286.rst |  95 +++++++++++++++++
>   drivers/hwmon/pmbus/Kconfig     |  10 ++
>   drivers/hwmon/pmbus/Makefile    |   1 +
>   drivers/hwmon/pmbus/ltc4286.c   | 183 ++++++++++++++++++++++++++++++++
>   5 files changed, 290 insertions(+)
>   create mode 100644 Documentation/hwmon/ltc4286.rst
>   create mode 100644 drivers/hwmon/pmbus/ltc4286.c
> 
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 72f4e6065bae..080827cc4c34 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -128,6 +128,7 @@ Hardware Monitoring Kernel Drivers
>      ltc4245
>      ltc4260
>      ltc4261
> +   ltc4286
>      max127
>      max15301
>      max16064
> diff --git a/Documentation/hwmon/ltc4286.rst b/Documentation/hwmon/ltc4286.rst
> new file mode 100644
> index 000000000000..2cd149676d86
> --- /dev/null
> +++ b/Documentation/hwmon/ltc4286.rst
> @@ -0,0 +1,95 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver ltc4286
> +=====================
> +
> +Supported chips:
> +
> +  * Analog Devices LTC4286
> +
> +    Prefix: 'ltc4286'
> +
> +    Addresses scanned: -
> +
> +    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4286.pdf
> +
> +  * Analog Devices LTC4287
> +
> +    Prefix: 'ltc4287'
> +
> +    Addresses scanned: -
> +
> +    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4287.pdf
> +
> +Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> +
> +
> +Description
> +-----------
> +
> +This driver supports hardware monitoring for Analog Devices LTC4286
> +and LTC4287 Hot-Swap Controller and Digital Power Monitors.
> +
> +LTC4286 and LTC4287 are hot-swap controllers that allow a circuit board
> +to be removed from or inserted into a live backplane. They also feature
> +current and voltage readback via an integrated 12 bit analog-to-digital
> +converter (ADC), accessed using a PMBus interface.
> +
> +The driver is a client driver to the core PMBus driver. Please see
> +Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
> +
> +
> +Usage Notes
> +-----------
> +
> +This driver does not auto-detect devices. You will have to instantiate the
> +devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
> +details.
> +
> +The shunt value in micro-ohms can be set via device tree at compile-time. Please
> +refer to the Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings
> +if the device tree is used.
> +
> +
> +Platform data support
> +---------------------
> +
> +The driver supports standard PMBus driver platform data. Please see
> +Documentation/hwmon/pmbus.rst for details.
> +
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported. Limits are read-write, history reset
> +attributes are write-only, all other attributes are read-only.
> +
> +======================= =======================================================
> +in1_label		"vin"
> +in1_input		Measured voltage.
> +in1_alarm		Input voltage alarm.
> +in1_min 		Minimum input voltage.
> +in1_max 		Maximum input voltage.
> +
> +in2_label		"vout1"
> +in2_input		Measured voltage.
> +in2_alarm		Output voltage alarm.
> +in2_min 		Minimum output voltage.
> +in2_max 		Maximum output voltage.
> +
> +curr1_label		"iout1"
> +curr1_input		Measured current.
> +curr1_alarm		Output current alarm.
> +curr1_max		Maximum current.
> +
> +power1_label		"pin"
> +power1_input		Input power.
> +power1_alarm		Input power alarm.
> +power1_max		Maximum poewr.
> +
> +temp1_input		Chip temperature.
> +temp1_min		Minimum chip temperature.
> +temp1_max		Maximum chip temperature.
> +temp1_crit		Critical chip temperature.
> +temp1_alarm		Chip temperature alarm.
> +======================= =======================================================
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index b4e93bd5835e..2d4f972e5a65 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -227,6 +227,16 @@ config SENSORS_LTC3815
>   	  This driver can also be built as a module. If so, the module will
>   	  be called ltc3815.
>   
> +config SENSORS_LTC4286
> +	bool "Analog Devices LTC4286"
> +	help
> +	  LTC4286 is an integrated solution for hot swap applications that
> +	  allows a board to be safely inserted and removed from a live
> +	  backplane.
> +	  This chip could be used to monitor voltage, current, ...etc.
> +	  If you say yes here you get hardware monitoring support for Analog
> +	  Devices LTC4286.
> +
>   config SENSORS_MAX15301
>   	tristate "Maxim MAX15301"
>   	help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 84ee960a6c2d..94e28f6d6a61 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
>   obj-$(CONFIG_SENSORS_LT7182S)	+= lt7182s.o
>   obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
>   obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o
> +obj-$(CONFIG_SENSORS_LTC4286)	+= ltc4286.o
>   obj-$(CONFIG_SENSORS_MAX15301)	+= max15301.o
>   obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
>   obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
> diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c
> new file mode 100644
> index 000000000000..e43e05579be1
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/ltc4286.c
> @@ -0,0 +1,183 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pmbus.h>
> +#include "pmbus.h"
> +
> +/* LTC4286 register */
> +#define LTC4286_MFR_CONFIG1	0xF2
> +
> +/* LTC4286 configuration */
> +#define VRANGE_SELECT_BIT	BIT(1)
> +
> +#define LTC4286_MFR_ID_SIZE	3
> +#define VRANGE_102P4		1
> +
> +/*
> + * Initialize the MBR as default settings which is referred to LTC4286 datasheet
> + * (March 22, 2022 version) table 3 page 16
> + */
> +static struct pmbus_driver_info ltc4286_info = {
> +	.pages = 1,
> +	.format[PSC_VOLTAGE_IN] = direct,
> +	.format[PSC_VOLTAGE_OUT] = direct,
> +	.format[PSC_CURRENT_OUT] = direct,
> +	.format[PSC_POWER] = direct,
> +	.format[PSC_TEMPERATURE] = direct,
> +	.m[PSC_VOLTAGE_IN] = 32,
> +	.b[PSC_VOLTAGE_IN] = 0,
> +	.R[PSC_VOLTAGE_IN] = 1,
> +	.m[PSC_VOLTAGE_OUT] = 32,
> +	.b[PSC_VOLTAGE_OUT] = 0,
> +	.R[PSC_VOLTAGE_OUT] = 1,
> +	.m[PSC_CURRENT_OUT] = 1024,
> +	.b[PSC_CURRENT_OUT] = 0,
> +	/*
> +	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
> +	 * However, the rsense value that user input is micro ohm.
> +	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
> +	 */
> +	.R[PSC_CURRENT_OUT] = 3 - 6,
> +	.m[PSC_POWER] = 1,
> +	.b[PSC_POWER] = 0,
> +	/*
> +	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
> +	 * However, the rsense value that user input is micro ohm.
> +	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
> +	 */
> +	.R[PSC_POWER] = 4 - 6,
> +	.m[PSC_TEMPERATURE] = 1,
> +	.b[PSC_TEMPERATURE] = 273,
> +	.R[PSC_TEMPERATURE] = 0,
> +	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
> +		   PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
> +		   PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
> +};
> +
> +static const struct i2c_device_id ltc4286_id[] = {
> +	{ "ltc4286", 0 },
> +	{ "ltc4287", 1 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ltc4286_id);
> +
> +static int ltc4286_probe(struct i2c_client *client)
> +{
> +	int ret;
> +	const struct i2c_device_id *mid;
> +	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
> +	struct pmbus_driver_info *info;
> +	u32 rsense;
> +
> +	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
> +	if (ret < 0) {
> +		return dev_err_probe(&client->dev, ret,
> +				     "Failed to read manufacturer id\n");
> +	}
> +
> +	/*
> +	 * Refer to ltc4286 datasheet page 20
> +	 * the manufacturer id is LTC
> +	 */
> +	if (ret != LTC4286_MFR_ID_SIZE ||
> +	    strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
> +		return dev_err_probe(&client->dev, ret,
> +				     "Manufacturer id mismatch\n");
> +	}
> +
> +	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
> +	if (ret < 0) {
> +		return dev_err_probe(&client->dev, ret,
> +				     "Failed to read manufacturer model\n");
> +	}
> +
> +	for (mid = ltc4286_id; mid->name[0]; mid++) {
> +		if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
> +			break;
> +	}
> +	if (!mid->name[0])
> +		return dev_err_probe(&client->dev, -ENODEV,
> +				     "Unsupported device\n");
> +
> +	if (of_property_read_u32(client->dev.of_node,
> +				 "shunt-resistor-micro-ohms", &rsense))
> +		rsense = 300; /* 0.3 mOhm if not set via DT */
> +
> +	if (rsense == 0)
> +		return -EINVAL;
> +
> +	/* Check for the latter MBR value won't overflow */
> +	if (rsense > (INT_MAX / 1024))
> +		return -EINVAL;
> +
> +	info = devm_kmemdup(&client->dev, &ltc4286_info, sizeof(*info),
> +			    GFP_KERNEL);
> +	if (!info)
> +		return -ENOMEM;
> +
> +	/* Check  MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */
> +	ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
> +	if (ret < 0)
> +		return dev_err_probe(
> +			&client->dev, ret,
> +			"Failed to read manufacturer configuration one\n");
> +
> +	if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
> +		/* The voltage range is 102.4 volts now */
> +		if (ret == VRANGE_102P4) {

This has to check VRANGE_SELECT_BIT, not the entire register.
Other register bit values are unknown.

		if (ret & VRANGE_SELECT_BIT)

Alternatively, something like
	int new, orig;
	...
	orig = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
	if (orig < 0)
		return dev_err_probe(...);
	new = orig;
	if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
		new &= ~VRANGE_SELECT_BIT;
		info->m[PSC_VOLTAGE_IN] = 128;
		info->m[PSC_VOLTAGE_OUT] = 128;
		info->m[PSC_POWER] = 4 * rsense;
	} else {
		new |= VRANGE_SELECT_BIT;
		info->m[PSC_POWER] = rsense;
	}
	if (new != orig) {
		ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1, new);
		if (ret)
			return dev_err_probe(...);
	}

seems cleaner to me, but that is your call.

Guenter
Delphine CC Chiu Nov. 23, 2023, 1:53 a.m. UTC | #2
> -----Original Message-----
> From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck
> Sent: Wednesday, November 22, 2023 12:14 AM
> To: Delphine_CC_Chiu/WYHQ/Wiwynn <Delphine_CC_Chiu@wiwynn.com>;
> patrick@stwcx.xyz; Jean Delvare <jdelvare@suse.com>; Jonathan Corbet
> <corbet@lwn.net>
> Cc: Rob Herring <robh+dt@kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@linaro.org>; Conor Dooley <conor+dt@kernel.org>;
> linux-i2c@vger.kernel.org; linux-hwmon@vger.kernel.org;
> devicetree@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-doc@vger.kernel.org
> Subject: Re: [PATCH v6 2/2] hwmon: pmbus: Add ltc4286 driver
> 
>   Security Reminder: Please be aware that this email is sent by an external
> sender.
> 
> On 11/20/23 21:07, Delphine CC Chiu wrote:
> > Add a driver to support ltc4286 chip
> >
> > Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> > ---
> > Changelog:
> >    v6 - Check VRANGE_SELECT before driver loading
> >    v5 - Check the overflow when reading rsense
> >       - Set default rsense value
> >    v4 - Add empty line before "config SENSORS_LTC4286" in Kconfig
> >       - Add ltc4286 to Documentation/hwmon/index.rst
> >       - Revise comment typo
> >       - Use devm_kmemdup instead of memcpy
> >       - Check MBR value before writting into
> >    v3 - Use dev_err_probe() instead of dev_err()
> >       - The VRANGE_SELECT bit only be written if it actually changed
> >       - Avoid the info pointer being overwritten
> >       - Check the MBR value range to avoid overflow
> >       - Revise ltc4286.rst to corrcet description
> >    v2 - Revise Linear Technologies LTC4286 to
> >         Analog Devices LTC4286 in Kconfig
> >       - Add more description for this driver in Kconfig
> >       - Add some comments for MBR setting in ltc4286.c
> >       - Add ltc4286.rst
> > ---
> >   Documentation/hwmon/index.rst   |   1 +
> >   Documentation/hwmon/ltc4286.rst |  95 +++++++++++++++++
> >   drivers/hwmon/pmbus/Kconfig     |  10 ++
> >   drivers/hwmon/pmbus/Makefile    |   1 +
> >   drivers/hwmon/pmbus/ltc4286.c   | 183
> ++++++++++++++++++++++++++++++++
> >   5 files changed, 290 insertions(+)
> >   create mode 100644 Documentation/hwmon/ltc4286.rst
> >   create mode 100644 drivers/hwmon/pmbus/ltc4286.c
> >
> > diff --git a/Documentation/hwmon/index.rst
> > b/Documentation/hwmon/index.rst index 72f4e6065bae..080827cc4c34
> > 100644
> > --- a/Documentation/hwmon/index.rst
> > +++ b/Documentation/hwmon/index.rst
> > @@ -128,6 +128,7 @@ Hardware Monitoring Kernel Drivers
> >      ltc4245
> >      ltc4260
> >      ltc4261
> > +   ltc4286
> >      max127
> >      max15301
> >      max16064
> > diff --git a/Documentation/hwmon/ltc4286.rst
> > b/Documentation/hwmon/ltc4286.rst new file mode 100644 index
> > 000000000000..2cd149676d86
> > --- /dev/null
> > +++ b/Documentation/hwmon/ltc4286.rst
> > @@ -0,0 +1,95 @@
> > +.. SPDX-License-Identifier: GPL-2.0-or-later
> > +
> > +Kernel driver ltc4286
> > +=====================
> > +
> > +Supported chips:
> > +
> > +  * Analog Devices LTC4286
> > +
> > +    Prefix: 'ltc4286'
> > +
> > +    Addresses scanned: -
> > +
> > +    Datasheet:
> > + https://www.analog.com/media/en/technical-documentation/data-sheets/
> > + ltc4286.pdf
> > +
> > +  * Analog Devices LTC4287
> > +
> > +    Prefix: 'ltc4287'
> > +
> > +    Addresses scanned: -
> > +
> > +    Datasheet:
> > + https://www.analog.com/media/en/technical-documentation/data-sheets/
> > + ltc4287.pdf
> > +
> > +Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
> > +
> > +
> > +Description
> > +-----------
> > +
> > +This driver supports hardware monitoring for Analog Devices LTC4286
> > +and LTC4287 Hot-Swap Controller and Digital Power Monitors.
> > +
> > +LTC4286 and LTC4287 are hot-swap controllers that allow a circuit
> > +board to be removed from or inserted into a live backplane. They also
> > +feature current and voltage readback via an integrated 12 bit
> > +analog-to-digital converter (ADC), accessed using a PMBus interface.
> > +
> > +The driver is a client driver to the core PMBus driver. Please see
> > +Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
> > +
> > +
> > +Usage Notes
> > +-----------
> > +
> > +This driver does not auto-detect devices. You will have to
> > +instantiate the devices explicitly. Please see
> > +Documentation/i2c/instantiating-devices.rst for details.
> > +
> > +The shunt value in micro-ohms can be set via device tree at
> > +compile-time. Please refer to the
> > +Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings
> if the device tree is used.
> > +
> > +
> > +Platform data support
> > +---------------------
> > +
> > +The driver supports standard PMBus driver platform data. Please see
> > +Documentation/hwmon/pmbus.rst for details.
> > +
> > +
> > +Sysfs entries
> > +-------------
> > +
> > +The following attributes are supported. Limits are read-write,
> > +history reset attributes are write-only, all other attributes are read-only.
> > +
> > +=======================
> =======================================================
> > +in1_label            "vin"
> > +in1_input            Measured voltage.
> > +in1_alarm            Input voltage alarm.
> > +in1_min              Minimum input voltage.
> > +in1_max              Maximum input voltage.
> > +
> > +in2_label            "vout1"
> > +in2_input            Measured voltage.
> > +in2_alarm            Output voltage alarm.
> > +in2_min              Minimum output voltage.
> > +in2_max              Maximum output voltage.
> > +
> > +curr1_label          "iout1"
> > +curr1_input          Measured current.
> > +curr1_alarm          Output current alarm.
> > +curr1_max            Maximum current.
> > +
> > +power1_label         "pin"
> > +power1_input         Input power.
> > +power1_alarm         Input power alarm.
> > +power1_max           Maximum poewr.
> > +
> > +temp1_input          Chip temperature.
> > +temp1_min            Minimum chip temperature.
> > +temp1_max            Maximum chip temperature.
> > +temp1_crit           Critical chip temperature.
> > +temp1_alarm          Chip temperature alarm.
> > +=======================
> > +=======================================================
> > diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> > index b4e93bd5835e..2d4f972e5a65 100644
> > --- a/drivers/hwmon/pmbus/Kconfig
> > +++ b/drivers/hwmon/pmbus/Kconfig
> > @@ -227,6 +227,16 @@ config SENSORS_LTC3815
> >         This driver can also be built as a module. If so, the module will
> >         be called ltc3815.
> >
> > +config SENSORS_LTC4286
> > +     bool "Analog Devices LTC4286"
> > +     help
> > +       LTC4286 is an integrated solution for hot swap applications that
> > +       allows a board to be safely inserted and removed from a live
> > +       backplane.
> > +       This chip could be used to monitor voltage, current, ...etc.
> > +       If you say yes here you get hardware monitoring support for
> Analog
> > +       Devices LTC4286.
> > +
> >   config SENSORS_MAX15301
> >       tristate "Maxim MAX15301"
> >       help
> > diff --git a/drivers/hwmon/pmbus/Makefile
> > b/drivers/hwmon/pmbus/Makefile index 84ee960a6c2d..94e28f6d6a61
> 100644
> > --- a/drivers/hwmon/pmbus/Makefile
> > +++ b/drivers/hwmon/pmbus/Makefile
> > @@ -24,6 +24,7 @@ obj-$(CONFIG_SENSORS_LM25066)       +=
> lm25066.o
> >   obj-$(CONFIG_SENSORS_LT7182S)       += lt7182s.o
> >   obj-$(CONFIG_SENSORS_LTC2978)       += ltc2978.o
> >   obj-$(CONFIG_SENSORS_LTC3815)       += ltc3815.o
> > +obj-$(CONFIG_SENSORS_LTC4286)        += ltc4286.o
> >   obj-$(CONFIG_SENSORS_MAX15301)      += max15301.o
> >   obj-$(CONFIG_SENSORS_MAX16064)      += max16064.o
> >   obj-$(CONFIG_SENSORS_MAX16601)      += max16601.o
> > diff --git a/drivers/hwmon/pmbus/ltc4286.c
> > b/drivers/hwmon/pmbus/ltc4286.c new file mode 100644 index
> > 000000000000..e43e05579be1
> > --- /dev/null
> > +++ b/drivers/hwmon/pmbus/ltc4286.c
> > @@ -0,0 +1,183 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +
> > +#include <linux/err.h>
> > +#include <linux/i2c.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/pmbus.h>
> > +#include "pmbus.h"
> > +
> > +/* LTC4286 register */
> > +#define LTC4286_MFR_CONFIG1  0xF2
> > +
> > +/* LTC4286 configuration */
> > +#define VRANGE_SELECT_BIT    BIT(1)
> > +
> > +#define LTC4286_MFR_ID_SIZE  3
> > +#define VRANGE_102P4         1
> > +
> > +/*
> > + * Initialize the MBR as default settings which is referred to
> > +LTC4286 datasheet
> > + * (March 22, 2022 version) table 3 page 16  */ static struct
> > +pmbus_driver_info ltc4286_info = {
> > +     .pages = 1,
> > +     .format[PSC_VOLTAGE_IN] = direct,
> > +     .format[PSC_VOLTAGE_OUT] = direct,
> > +     .format[PSC_CURRENT_OUT] = direct,
> > +     .format[PSC_POWER] = direct,
> > +     .format[PSC_TEMPERATURE] = direct,
> > +     .m[PSC_VOLTAGE_IN] = 32,
> > +     .b[PSC_VOLTAGE_IN] = 0,
> > +     .R[PSC_VOLTAGE_IN] = 1,
> > +     .m[PSC_VOLTAGE_OUT] = 32,
> > +     .b[PSC_VOLTAGE_OUT] = 0,
> > +     .R[PSC_VOLTAGE_OUT] = 1,
> > +     .m[PSC_CURRENT_OUT] = 1024,
> > +     .b[PSC_CURRENT_OUT] = 0,
> > +     /*
> > +      * The rsense value used in MBR formula in LTC4286 datasheet
> should be ohm unit.
> > +      * However, the rsense value that user input is micro ohm.
> > +      * Thus, the MBR setting which involves rsense should be shifted by
> 6 digits.
> > +      */
> > +     .R[PSC_CURRENT_OUT] = 3 - 6,
> > +     .m[PSC_POWER] = 1,
> > +     .b[PSC_POWER] = 0,
> > +     /*
> > +      * The rsense value used in MBR formula in LTC4286 datasheet
> should be ohm unit.
> > +      * However, the rsense value that user input is micro ohm.
> > +      * Thus, the MBR setting which involves rsense should be shifted by
> 6 digits.
> > +      */
> > +     .R[PSC_POWER] = 4 - 6,
> > +     .m[PSC_TEMPERATURE] = 1,
> > +     .b[PSC_TEMPERATURE] = 273,
> > +     .R[PSC_TEMPERATURE] = 0,
> > +     .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT |
> PMBUS_HAVE_IOUT |
> > +                PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP |
> PMBUS_HAVE_STATUS_VOUT |
> > +                PMBUS_HAVE_STATUS_IOUT |
> PMBUS_HAVE_STATUS_TEMP, };
> > +
> > +static const struct i2c_device_id ltc4286_id[] = {
> > +     { "ltc4286", 0 },
> > +     { "ltc4287", 1 },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(i2c, ltc4286_id);
> > +
> > +static int ltc4286_probe(struct i2c_client *client) {
> > +     int ret;
> > +     const struct i2c_device_id *mid;
> > +     u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
> > +     struct pmbus_driver_info *info;
> > +     u32 rsense;
> > +
> > +     ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID,
> block_buffer);
> > +     if (ret < 0) {
> > +             return dev_err_probe(&client->dev, ret,
> > +                                  "Failed to read manufacturer
> id\n");
> > +     }
> > +
> > +     /*
> > +      * Refer to ltc4286 datasheet page 20
> > +      * the manufacturer id is LTC
> > +      */
> > +     if (ret != LTC4286_MFR_ID_SIZE ||
> > +         strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
> > +             return dev_err_probe(&client->dev, ret,
> > +                                  "Manufacturer id mismatch\n");
> > +     }
> > +
> > +     ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL,
> block_buffer);
> > +     if (ret < 0) {
> > +             return dev_err_probe(&client->dev, ret,
> > +                                  "Failed to read manufacturer
> model\n");
> > +     }
> > +
> > +     for (mid = ltc4286_id; mid->name[0]; mid++) {
> > +             if (!strncasecmp(mid->name, block_buffer,
> strlen(mid->name)))
> > +                     break;
> > +     }
> > +     if (!mid->name[0])
> > +             return dev_err_probe(&client->dev, -ENODEV,
> > +                                  "Unsupported device\n");
> > +
> > +     if (of_property_read_u32(client->dev.of_node,
> > +                              "shunt-resistor-micro-ohms",
> &rsense))
> > +             rsense = 300; /* 0.3 mOhm if not set via DT */
> > +
> > +     if (rsense == 0)
> > +             return -EINVAL;
> > +
> > +     /* Check for the latter MBR value won't overflow */
> > +     if (rsense > (INT_MAX / 1024))
> > +             return -EINVAL;
> > +
> > +     info = devm_kmemdup(&client->dev, &ltc4286_info, sizeof(*info),
> > +                         GFP_KERNEL);
> > +     if (!info)
> > +             return -ENOMEM;
> > +
> > +     /* Check  MFR1 CONFIG register bit 1 VRANGE_SELECT before driver
> loading */
> > +     ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
> > +     if (ret < 0)
> > +             return dev_err_probe(
> > +                     &client->dev, ret,
> > +                     "Failed to read manufacturer configuration
> > + one\n");
> > +
> > +     if (device_property_read_bool(&client->dev,
> "adi,vrange-low-enable")) {
> > +             /* The voltage range is 102.4 volts now */
> > +             if (ret == VRANGE_102P4) {
> 
> This has to check VRANGE_SELECT_BIT, not the entire register.
> Other register bit values are unknown.
> 
>                 if (ret & VRANGE_SELECT_BIT)
> 
> Alternatively, something like
>         int new, orig;
>         ...
>         orig = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
>         if (orig < 0)
>                 return dev_err_probe(...);
>         new = orig;
>         if (device_property_read_bool(&client->dev,
> "adi,vrange-low-enable")) {
>                 new &= ~VRANGE_SELECT_BIT;
>                 info->m[PSC_VOLTAGE_IN] = 128;
>                 info->m[PSC_VOLTAGE_OUT] = 128;
>                 info->m[PSC_POWER] = 4 * rsense;
>         } else {
>                 new |= VRANGE_SELECT_BIT;
>                 info->m[PSC_POWER] = rsense;
>         }
>         if (new != orig) {
>                 ret = i2c_smbus_write_word_data(client,
> LTC4286_MFR_CONFIG1, new);
>                 if (ret)
>                         return dev_err_probe(...);
>         }
> 
> seems cleaner to me, but that is your call.

We will follow your suggestion to revise the code
Thanks.

> 
> Guenter
diff mbox series

Patch

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 72f4e6065bae..080827cc4c34 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -128,6 +128,7 @@  Hardware Monitoring Kernel Drivers
    ltc4245
    ltc4260
    ltc4261
+   ltc4286
    max127
    max15301
    max16064
diff --git a/Documentation/hwmon/ltc4286.rst b/Documentation/hwmon/ltc4286.rst
new file mode 100644
index 000000000000..2cd149676d86
--- /dev/null
+++ b/Documentation/hwmon/ltc4286.rst
@@ -0,0 +1,95 @@ 
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver ltc4286
+=====================
+
+Supported chips:
+
+  * Analog Devices LTC4286
+
+    Prefix: 'ltc4286'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4286.pdf
+
+  * Analog Devices LTC4287
+
+    Prefix: 'ltc4287'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4287.pdf
+
+Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices LTC4286
+and LTC4287 Hot-Swap Controller and Digital Power Monitors.
+
+LTC4286 and LTC4287 are hot-swap controllers that allow a circuit board
+to be removed from or inserted into a live backplane. They also feature
+current and voltage readback via an integrated 12 bit analog-to-digital
+converter (ADC), accessed using a PMBus interface.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
+details.
+
+The shunt value in micro-ohms can be set via device tree at compile-time. Please
+refer to the Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings
+if the device tree is used.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data. Please see
+Documentation/hwmon/pmbus.rst for details.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write, history reset
+attributes are write-only, all other attributes are read-only.
+
+======================= =======================================================
+in1_label		"vin"
+in1_input		Measured voltage.
+in1_alarm		Input voltage alarm.
+in1_min 		Minimum input voltage.
+in1_max 		Maximum input voltage.
+
+in2_label		"vout1"
+in2_input		Measured voltage.
+in2_alarm		Output voltage alarm.
+in2_min 		Minimum output voltage.
+in2_max 		Maximum output voltage.
+
+curr1_label		"iout1"
+curr1_input		Measured current.
+curr1_alarm		Output current alarm.
+curr1_max		Maximum current.
+
+power1_label		"pin"
+power1_input		Input power.
+power1_alarm		Input power alarm.
+power1_max		Maximum poewr.
+
+temp1_input		Chip temperature.
+temp1_min		Minimum chip temperature.
+temp1_max		Maximum chip temperature.
+temp1_crit		Critical chip temperature.
+temp1_alarm		Chip temperature alarm.
+======================= =======================================================
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index b4e93bd5835e..2d4f972e5a65 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -227,6 +227,16 @@  config SENSORS_LTC3815
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc3815.
 
+config SENSORS_LTC4286
+	bool "Analog Devices LTC4286"
+	help
+	  LTC4286 is an integrated solution for hot swap applications that
+	  allows a board to be safely inserted and removed from a live
+	  backplane.
+	  This chip could be used to monitor voltage, current, ...etc.
+	  If you say yes here you get hardware monitoring support for Analog
+	  Devices LTC4286.
+
 config SENSORS_MAX15301
 	tristate "Maxim MAX15301"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 84ee960a6c2d..94e28f6d6a61 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -24,6 +24,7 @@  obj-$(CONFIG_SENSORS_LM25066)	+= lm25066.o
 obj-$(CONFIG_SENSORS_LT7182S)	+= lt7182s.o
 obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o
+obj-$(CONFIG_SENSORS_LTC4286)	+= ltc4286.o
 obj-$(CONFIG_SENSORS_MAX15301)	+= max15301.o
 obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
 obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c
new file mode 100644
index 000000000000..e43e05579be1
--- /dev/null
+++ b/drivers/hwmon/pmbus/ltc4286.c
@@ -0,0 +1,183 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+/* LTC4286 register */
+#define LTC4286_MFR_CONFIG1	0xF2
+
+/* LTC4286 configuration */
+#define VRANGE_SELECT_BIT	BIT(1)
+
+#define LTC4286_MFR_ID_SIZE	3
+#define VRANGE_102P4		1
+
+/*
+ * Initialize the MBR as default settings which is referred to LTC4286 datasheet
+ * (March 22, 2022 version) table 3 page 16
+ */
+static struct pmbus_driver_info ltc4286_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = direct,
+	.format[PSC_VOLTAGE_OUT] = direct,
+	.format[PSC_CURRENT_OUT] = direct,
+	.format[PSC_POWER] = direct,
+	.format[PSC_TEMPERATURE] = direct,
+	.m[PSC_VOLTAGE_IN] = 32,
+	.b[PSC_VOLTAGE_IN] = 0,
+	.R[PSC_VOLTAGE_IN] = 1,
+	.m[PSC_VOLTAGE_OUT] = 32,
+	.b[PSC_VOLTAGE_OUT] = 0,
+	.R[PSC_VOLTAGE_OUT] = 1,
+	.m[PSC_CURRENT_OUT] = 1024,
+	.b[PSC_CURRENT_OUT] = 0,
+	/*
+	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
+	 * However, the rsense value that user input is micro ohm.
+	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
+	 */
+	.R[PSC_CURRENT_OUT] = 3 - 6,
+	.m[PSC_POWER] = 1,
+	.b[PSC_POWER] = 0,
+	/*
+	 * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit.
+	 * However, the rsense value that user input is micro ohm.
+	 * Thus, the MBR setting which involves rsense should be shifted by 6 digits.
+	 */
+	.R[PSC_POWER] = 4 - 6,
+	.m[PSC_TEMPERATURE] = 1,
+	.b[PSC_TEMPERATURE] = 273,
+	.R[PSC_TEMPERATURE] = 0,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+		   PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
+		   PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
+};
+
+static const struct i2c_device_id ltc4286_id[] = {
+	{ "ltc4286", 0 },
+	{ "ltc4287", 1 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ltc4286_id);
+
+static int ltc4286_probe(struct i2c_client *client)
+{
+	int ret;
+	const struct i2c_device_id *mid;
+	u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
+	struct pmbus_driver_info *info;
+	u32 rsense;
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
+	if (ret < 0) {
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read manufacturer id\n");
+	}
+
+	/*
+	 * Refer to ltc4286 datasheet page 20
+	 * the manufacturer id is LTC
+	 */
+	if (ret != LTC4286_MFR_ID_SIZE ||
+	    strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
+		return dev_err_probe(&client->dev, ret,
+				     "Manufacturer id mismatch\n");
+	}
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
+	if (ret < 0) {
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read manufacturer model\n");
+	}
+
+	for (mid = ltc4286_id; mid->name[0]; mid++) {
+		if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
+			break;
+	}
+	if (!mid->name[0])
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported device\n");
+
+	if (of_property_read_u32(client->dev.of_node,
+				 "shunt-resistor-micro-ohms", &rsense))
+		rsense = 300; /* 0.3 mOhm if not set via DT */
+
+	if (rsense == 0)
+		return -EINVAL;
+
+	/* Check for the latter MBR value won't overflow */
+	if (rsense > (INT_MAX / 1024))
+		return -EINVAL;
+
+	info = devm_kmemdup(&client->dev, &ltc4286_info, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	/* Check  MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */
+	ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
+	if (ret < 0)
+		return dev_err_probe(
+			&client->dev, ret,
+			"Failed to read manufacturer configuration one\n");
+
+	if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) {
+		/* The voltage range is 102.4 volts now */
+		if (ret == VRANGE_102P4) {
+			/* Set MFR1 CONFIG register bit 1 VRANGE_SELECT */
+			ret &= ~VRANGE_SELECT_BIT; /* VRANGE_SELECT = 0, 25.6 volts */
+			ret = i2c_smbus_write_word_data(
+				client, LTC4286_MFR_CONFIG1, ret);
+			if (ret < 0)
+				return dev_err_probe(&client->dev, ret,
+						     "Failed to set vrange\n");
+		}
+
+		info->m[PSC_VOLTAGE_IN] = 128;
+		info->m[PSC_VOLTAGE_OUT] = 128;
+		info->m[PSC_POWER] = 4 * rsense;
+	} else {
+		/* The voltage range is 25.6 volts now */
+		if (ret != VRANGE_102P4) {
+			/* Set MFR1 CONFIG register bit 1 VRANGE_SELECT */
+			ret |= VRANGE_SELECT_BIT; /* VRANGE_SELECT = 1, 102.4 volts */
+			ret = i2c_smbus_write_word_data(
+				client, LTC4286_MFR_CONFIG1, ret);
+			if (ret < 0)
+				return dev_err_probe(&client->dev, ret,
+						     "Failed to set vrange\n");
+		}
+
+		info->m[PSC_POWER] = rsense;
+	}
+
+	info->m[PSC_CURRENT_OUT] = 1024 * rsense;
+
+	return pmbus_do_probe(client, info);
+}
+
+static const struct of_device_id ltc4286_of_match[] = {
+	{ .compatible = "lltc,ltc4286" },
+	{ .compatible = "lltc,ltc4287" },
+	{}
+};
+
+static struct i2c_driver ltc4286_driver = {
+	.driver = {
+		.name = "ltc4286",
+		.of_match_table = ltc4286_of_match,
+	},
+	.probe = ltc4286_probe,
+	.id_table = ltc4286_id,
+};
+
+module_i2c_driver(ltc4286_driver);
+
+MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@wiwynn.com>");
+MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
+MODULE_LICENSE("GPL");