[2/2] hwmon: pmbus: add driver for ltp8800-1a, ltp8800-4a, and ltp8800-2

LTP8800-1A 54V, 150A DC/DC µModule Regulator with PMBus Interface
LTP8800-4A 54V, 200A DC/DC µModule Regulator with PMBus Interface
LTP8800-2 54V, 135A DC/DC μModule Regulator with PMBus Interface

Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
---
 Documentation/hwmon/index.rst   |   1 +
 Documentation/hwmon/ltp8800.rst | 103 ++++++++++++++++++++++++++++++++
 MAINTAINERS                     |   2 +
 drivers/hwmon/pmbus/Kconfig     |  18 ++++++
 drivers/hwmon/pmbus/Makefile    |   1 +
 drivers/hwmon/pmbus/ltp8800.c   |  74 +++++++++++++++++++++++
 6 files changed, 199 insertions(+)
 create mode 100644 Documentation/hwmon/ltp8800.rst
 create mode 100644 drivers/hwmon/pmbus/ltp8800.c

On 10/29/24 06:01, Cedric Encarnacion wrote:
> LTP8800-1A 54V, 150A DC/DC µModule Regulator with PMBus Interface
> LTP8800-4A 54V, 200A DC/DC µModule Regulator with PMBus Interface
> LTP8800-2 54V, 135A DC/DC μModule Regulator with PMBus Interface
> 

Please provide a short description.

> Signed-off-by: Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
> ---
>   Documentation/hwmon/index.rst   |   1 +
>   Documentation/hwmon/ltp8800.rst | 103 ++++++++++++++++++++++++++++++++
>   MAINTAINERS                     |   2 +
>   drivers/hwmon/pmbus/Kconfig     |  18 ++++++
>   drivers/hwmon/pmbus/Makefile    |   1 +
>   drivers/hwmon/pmbus/ltp8800.c   |  74 +++++++++++++++++++++++
>   6 files changed, 199 insertions(+)
>   create mode 100644 Documentation/hwmon/ltp8800.rst
>   create mode 100644 drivers/hwmon/pmbus/ltp8800.c
> 
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 4d15664bc41e..d51960f58e43 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -136,6 +136,7 @@ Hardware Monitoring Kernel Drivers
>      ltc4261
>      ltc4282
>      ltc4286
> +   ltp8800
>      max127
>      max15301
>      max16064
> diff --git a/Documentation/hwmon/ltp8800.rst b/Documentation/hwmon/ltp8800.rst
> new file mode 100644
> index 000000000000..dea73f60c3d7
> --- /dev/null
> +++ b/Documentation/hwmon/ltp8800.rst
> @@ -0,0 +1,103 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver ltp8800
> +=====================
> +
> +Supported chips:
> +
> +	* Analog Devices LTP8800-1A
> +
> +		Prefix: 'ltp8800-1a'
> +
> +		Addresses scanned: I2C 0x40 - 0x4F
> +

No, the chips are not scanned.

> +		Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltp8800-1a.pdf
> +
> +	* Analog Devices LTP8800-4A
> +
> +		Prefix: 'ltp8800-4a'
> +
> +		Addresses scanned: I2C 0x40 - 0x4F
> +
> +		Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltp8800-4a.pdf
> +
> +	* Analog Devices LTP8800-2
> +
> +		Prefix: 'ltp8800-2'
> +
> +		Addresses scanned: I2C 0x40 - 0x4F
> +
> +		Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltp8800-2.pdf
> +
> +Authors:
> +		- Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
> +
> +
> +Description
> +-----------
> +
> +The LTP8800 is a family of step-down μModule regulators that provides
> +microprocessor core voltage from 54V power distribution architecture. LTP8800
> +features telemetry monitoring of input/output voltage, input current, output
> +power, and temperature over PMBus.
> +
> +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.
> +
> +Platform data support
> +---------------------
> +
> +The driver supports standard PMBus driver platform data. Please see
> +Documentation/hwmon/pmbus.rst for details.
> +
> +Sysfs Attributes
> +----------------
> +
> +======================= ===========================
> +curr1_label		"iin"
> +curr1_input		Measured input current
> +curr1_crit		Critical maximum current
> +curr1_crit_alarm	Current critical high alarm
> +
> +curr2_label		"iout1"
> +curr2_input		Measured output current
> +curr2_lcrit		Critical minimum current
> +curr2_crit		Critical maximum current
> +curr2_max		Maximum output current
> +curr2_alarm		Current alarm
> +
> +in1_label		"vin"
> +in1_input		Measured input voltage
> +in1_lcrit		Critical minimum input voltage
> +in1_lcrit_alarm		Input voltage critical low alarm
> +in1_crit		Critical maximum input voltage
> +in1_crit_alarm		Input voltage critical high alarm
> +
> +in2_label		"vout1"
> +in2_input		Measured output voltage
> +in2_lcrit		Critical minimum output voltage
> +in2_lcrit_alarm		Output voltage critical low alarm
> +in2_crit		Critical maximum output voltage
> +in2_crit_alarm		Output voltage critical high alarm
> +in2_max			Maximum output voltage
> +in2_max_alarm		Output voltage high alarm
> +in2_min			Minimum output voltage
> +in2_min_alarm		Output voltage low alarm
> +
> +power1_label		"pout1"
> +power1_input		Measured output power
> +power1_crit		Critical maximum output power
> +
> +temp1_input		Measured temperature
> +temp1_lcrit		Critical low temperature
> +temp1_lcrit_alarm		Chip temperature critical low alarm
> +temp1_crit		Critical high temperature
> +temp1_crit_alarm		Chip temperature critical high alarm
> +======================= ===========================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a6abf7243b94..5e7df53eb4a0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -13559,6 +13559,8 @@ LTP8800 HARDWARE MONITOR DRIVER
>   M:	Cedric Encarnacion <cedricjustine.encarnacion@analog.com>
>   L:	linux-hwmon@vger.kernel.org
>   S:	Supported
> +F:	Documentation/hwmon/ltp8800.rst
> +F:	drivers/hwmon/pmbus/ltp8800.c
>   
>   LYNX 28G SERDES PHY DRIVER
>   M:	Ioana Ciornei <ioana.ciornei@nxp.com>
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index a4f02cad92fd..33e6da249ac8 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -247,6 +247,24 @@ config SENSORS_LTC4286
>   	  If you say yes here you get hardware monitoring support for Analog
>   	  Devices LTC4286.
>   
> +config SENSORS_LTP8800
> +	tristate "Analog Devices LTP8800 and compatibles"
> +	help
> +	  If you say yes here you get hardware monitoring support for Analog
> +	  Devices LTP8800-1A, LTP8800-4A, and LTP8800-2.
> +
> +	  This driver can also be built as a module. If so, the module will
> +	  be called ltp8800.
> +
> +config SENSORS_LTP8800_REGULATOR
> +	bool "Regulator support for LTP8800 and compatibles"
> +	depends on SENSORS_LTP8800 && REGULATOR
> +	help
> +	  If you say yes here you get regulator support for Analog Devices
> +	  LTP8800-1A, LTP8800-4A, and LTP8800-2. LTP8800 is a family of DC/DC
> +	  µModule regulators that can provide microprocessor power from 54V
> +	  power distribution architecture.
> +
>   config SENSORS_MAX15301
>   	tristate "Maxim MAX15301"
>   	help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index d00bcc758b97..aa5bbdb4a806 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -26,6 +26,7 @@ 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-$(CONFIG_SENSORS_LTP8800)	+= ltp8800.o
>   obj-$(CONFIG_SENSORS_MAX15301)	+= max15301.o
>   obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
>   obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
> diff --git a/drivers/hwmon/pmbus/ltp8800.c b/drivers/hwmon/pmbus/ltp8800.c
> new file mode 100644
> index 000000000000..a377f2e2b001
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/ltp8800.c
> @@ -0,0 +1,74 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Hardware monitoring driver for Analog Devices LTP8800
> + *
> + * Copyright (C) 2024 Analog Devices, Inc.
> + */
> +#include <linux/bits.h>

Is this used anywhere ? I don''t immediately see it.

> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include "pmbus.h"
> +
> +static const struct regulator_desc ltp8800_reg_desc[] = {
> +	PMBUS_REGULATOR("vout", 0),
> +};
> +
> +static struct pmbus_driver_info ltp8800_info = {
> +	.pages = 1,
> +	.format[PSC_VOLTAGE_IN] = linear,
> +	.format[PSC_VOLTAGE_OUT] = linear,
> +	.format[PSC_CURRENT_IN] = linear,
> +	.format[PSC_TEMPERATURE] = linear,
> +	.func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
> +		   PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
> +		   PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT |
> +		   PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP |
> +		   PMBUS_HAVE_POUT,
> +};
> +
> +static int ltp8800_probe(struct i2c_client *client)
> +{
> +	if (!i2c_check_functionality(client->adapter,
> +				     I2C_FUNC_SMBUS_READ_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_READ_WORD_DATA))
> +		return -ENODEV;
> +

This is also checked in pmbus_do_probe().

> +	if (IS_ENABLED(CONFIG_SENSORS_LTP8800_REGULATOR)) {
> +		ltp8800_info.num_regulators = 1;
> +		ltp8800_info.reg_desc = ltp8800_reg_desc;
> +	}

This can be set directly in ltp8800_info.

> +
> +	return pmbus_do_probe(client, &ltp8800_info);
> +}
> +
> +static const struct i2c_device_id ltp8800_id[] = {
> +	{"ltp8800-1a", 0},
> +	{"ltp8800-2", 0},
> +	{"ltp8800-4a", 0},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, ltp8800_id);
> +
> +static const struct of_device_id ltp8800_of_match[] = {
> +	{ .compatible = "adi,ltp8800-1a"},
> +	{ .compatible = "adi,ltp8800-2"},
> +	{ .compatible = "adi,ltp8800-4a"},

As mentioned in the other patch, I don't see the point of having three
compatible entries and three device IDs.

Guenter

> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, ltp8800_of_match);
> +
> +static struct i2c_driver ltp8800_driver = {
> +	.driver = {
> +		.name = "ltp8800",
> +		.of_match_table = ltp8800_of_match,
> +	},
> +	.probe = ltp8800_probe,
> +	.id_table = ltp8800_id,
> +};
> +module_i2c_driver(ltp8800_driver);
> +
> +MODULE_AUTHOR("Cedric Encarnacion <cedricjustine.encarnacion@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices LTP8800 HWMON PMBus Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(PMBUS);