Re: [PATCH v11 2/2] mfd: max597x: Add support for MAX5970 and MAX5978

[Naresh Solanki <naresh.solanki@9elements.com>]

On 17-11-2022 03:45 pm, Lee Jones wrote:
> On Wed, 16 Nov 2022, Naresh Solanki wrote:
> 
>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>
>> Implement a regulator driver with IRQ support for fault management.
>> Written against documentation [1] and [2] and tested on real hardware.
>>
>> Every channel has its own regulator supplies nammed 'vss1-supply' and
>> 'vss2-supply'. The regulator supply is used to determine the output
>> voltage, as the smart switch provides no output regulation.
>> The driver requires the 'shunt-resistor-micro-ohms' property to be
>> present in Device Tree to properly calculate current related
>> values.
>>
>> Datasheet links:
>> 1: https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
>> 2: https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
>>
>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>> Co-developed-by: Marcello Sylvester Bauer <sylv@sylv.io>
>> Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
>> Co-developed-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>> ---
>>   drivers/mfd/Kconfig         |  12 +++++
>>   drivers/mfd/Makefile        |   1 +
>>   drivers/mfd/max597x.c       |  93 +++++++++++++++++++++++++++++++++
>>   include/linux/mfd/max597x.h | 101 ++++++++++++++++++++++++++++++++++++
>>   4 files changed, 207 insertions(+)
>>   create mode 100644 drivers/mfd/max597x.c
>>   create mode 100644 include/linux/mfd/max597x.h
> 
> Ignoring my comments won't make them go away. :)
> 
> Please tell me why you need a whole new driver, instead of adding
> support to simple-mfd-i2c?
> 
I felt current implementation to be simpler, clearer & straight forward.

>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 8b93856de432..416fe7986b7b 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -253,6 +253,18 @@ config MFD_MADERA_SPI
>>   	  Support for the Cirrus Logic Madera platform audio SoC
>>   	  core functionality controlled via SPI.
>>   
>> +config MFD_MAX597X
>> +	tristate "Maxim 597x Power Switch and Monitor"
>> +	depends on I2C
>> +	depends on OF
>> +	select MFD_CORE
>> +	select REGMAP_I2C
>> +	help
>> +	  This driver controls a Maxim 5970/5978 switch via I2C bus.
>> +	  The MAX5970/5978 is a smart switch with no output regulation, but
>> +	  fault protection and voltage and current monitoring capabilities.
>> +	  Also it supports upto 4 indication LEDs.
>> +
>>   config MFD_CS47L15
>>   	bool "Cirrus Logic CS47L15"
>>   	select PINCTRL_CS47L15
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index 7ed3ef4a698c..819d711fa748 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -161,6 +161,7 @@ obj-$(CONFIG_MFD_DA9063)	+= da9063.o
>>   obj-$(CONFIG_MFD_DA9150)	+= da9150-core.o
>>   
>>   obj-$(CONFIG_MFD_MAX14577)	+= max14577.o
>> +obj-$(CONFIG_MFD_MAX597X)	+= max597x.o
>>   obj-$(CONFIG_MFD_MAX77620)	+= max77620.o
>>   obj-$(CONFIG_MFD_MAX77650)	+= max77650.o
>>   obj-$(CONFIG_MFD_MAX77686)	+= max77686.o
>> diff --git a/drivers/mfd/max597x.c b/drivers/mfd/max597x.c
>> new file mode 100644
>> index 000000000000..45838413f24a
>> --- /dev/null
>> +++ b/drivers/mfd/max597x.c
>> @@ -0,0 +1,93 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Maxim MAX5970/MAX5978 Power Switch & Monitor
>> + *
>> + * Copyright (c) 2022 9elements GmbH
>> + *
>> + * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/max597x.h>
>> +#include <linux/regmap.h>
>> +
>> +static const struct regmap_config max597x_regmap_config = {
>> +	.reg_bits = 8,
>> +	.val_bits = 8,
>> +	.max_register = MAX_REGISTERS,
>> +};
>> +
>> +static const struct mfd_cell max597x_cells[] = {
>> +	{ .name = "max597x-regulator", },
>> +	{ .name = "max597x-iio", },
>> +	{ .name = "max597x-led", },
>> +};
>> +
>> +static int max597x_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
>> +{
>> +	struct max597x_data *ddata;
>> +	enum max597x_chip_type chip = id->driver_data;
>> +
>> +	ddata = devm_kzalloc(&i2c->dev, sizeof(*ddata),	GFP_KERNEL);
>> +	if (!ddata)
>> +		return -ENOMEM;
>> +
>> +	/*
>> +	 * Based on chip type, Initialize the number of switch. This is needed by
>> +	 * regulator & iio cells.
>> +	 */
>> +	switch (chip) {
>> +	case MAX597x_TYPE_MAX5970:
>> +		ddata->num_switches = MAX5970_NUM_SWITCHES;
>> +		break;
>> +	case MAX597x_TYPE_MAX5978:
>> +		ddata->num_switches = MAX5978_NUM_SWITCHES;
>> +		break;
>> +	}
>> +
>> +	ddata->regmap = devm_regmap_init_i2c(i2c, &max597x_regmap_config);
>> +	if (IS_ERR(ddata->regmap)) {
>> +		dev_err(&i2c->dev, "Failed to initialize regmap");
>> +		return PTR_ERR(ddata->regmap);
>> +	}
>> +
>> +	/* IRQ used by regulator cell */
>> +	ddata->irq = i2c->irq;
>> +	ddata->dev = &i2c->dev;
>> +	i2c_set_clientdata(i2c, ddata);
>> +
>> +	return devm_mfd_add_devices(ddata->dev, PLATFORM_DEVID_AUTO,
>> +				    max597x_cells, ARRAY_SIZE(max597x_cells),
>> +				    NULL, 0, NULL);
>> +}
>> +
>> +static const struct i2c_device_id max597x_table[] = {
>> +	{ .name = "max5970", MAX597x_TYPE_MAX5970 },
>> +	{ .name = "max5978", MAX597x_TYPE_MAX5978 },
>> +	{}
>> +};
>> +
>> +MODULE_DEVICE_TABLE(i2c, max597x_table);
>> +
>> +static const struct of_device_id max597x_of_match[] = {
>> +	{ .compatible = "maxim,max5970" },
>> +	{ .compatible = "maxim,max5978" },
>> +	{}
>> +};
>> +
>> +MODULE_DEVICE_TABLE(of, max597x_of_match);
>> +
>> +static struct i2c_driver max597x_driver = {
>> +	.id_table = max597x_table,
>> +	.driver = {
>> +		  .name = "max597x",
>> +		  .of_match_table = of_match_ptr(max597x_of_match),
>> +		  },
>> +	.probe = max597x_probe,
>> +};
>> +module_i2c_driver(max597x_driver);
>> +
>> +MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@9elements.com>");
>> +MODULE_DESCRIPTION("MAX597X Power Switch and Monitor");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/include/linux/mfd/max597x.h b/include/linux/mfd/max597x.h
>> new file mode 100644
>> index 000000000000..706eff9c50a4
>> --- /dev/null
>> +++ b/include/linux/mfd/max597x.h
>> @@ -0,0 +1,101 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Maxim MAX5970/MAX5978 Power Switch & Monitor
>> + *
>> + * Copyright (c) 2022 9elements GmbH
>> + *
>> + * Author: Patrick Rudolph <patrick.rudolph@9elements.com>
>> + */
>> +
>> +#ifndef MFD_MAX597X_H
>> +#define MFD_MAX597X_H
>> +
>> +#include <linux/device.h>
>> +#include <linux/regmap.h>
>> +
>> +#define MAX5970_NUM_SWITCHES 2
>> +#define MAX5978_NUM_SWITCHES 1
>> +#define MAX597X_NUM_LEDS     4
>> +
>> +enum max597x_chip_type {
>> +	MAX597x_TYPE_MAX5978 = 1,
>> +	MAX597x_TYPE_MAX5970,
>> +};
>> +
>> +#define MAX5970_REG_CURRENT_L(ch)		(0x01 + (ch) * 4)
>> +#define MAX5970_REG_CURRENT_H(ch)		(0x00 + (ch) * 4)
>> +#define MAX5970_REG_VOLTAGE_L(ch)		(0x03 + (ch) * 4)
>> +#define MAX5970_REG_VOLTAGE_H(ch)		(0x02 + (ch) * 4)
>> +#define MAX5970_REG_MON_RANGE			0x18
>> +#define  MAX5970_MON_MASK				0x3
>> +#define  MAX5970_MON(reg, ch)		(((reg) >> ((ch) * 2)) & MAX5970_MON_MASK)
>> +#define  MAX5970_MON_MAX_RANGE_UV		16000000
>> +
>> +#define MAX5970_REG_CH_UV_WARN_H(ch)	(0x1A + (ch) * 10)
>> +#define MAX5970_REG_CH_UV_WARN_L(ch)	(0x1B + (ch) * 10)
>> +#define MAX5970_REG_CH_UV_CRIT_H(ch)	(0x1C + (ch) * 10)
>> +#define MAX5970_REG_CH_UV_CRIT_L(ch)	(0x1D + (ch) * 10)
>> +#define MAX5970_REG_CH_OV_WARN_H(ch)	(0x1E + (ch) * 10)
>> +#define MAX5970_REG_CH_OV_WARN_L(ch)	(0x1F + (ch) * 10)
>> +#define MAX5970_REG_CH_OV_CRIT_H(ch)	(0x20 + (ch) * 10)
>> +#define MAX5970_REG_CH_OV_CRIT_L(ch)	(0x21 + (ch) * 10)
>> +
>> +#define  MAX5970_VAL2REG_H(x)			(((x) >> 2) & 0xFF)
>> +#define  MAX5970_VAL2REG_L(x)			((x) & 0x3)
>> +
>> +#define MAX5970_REG_DAC_FAST(ch)		(0x2E + (ch))
>> +
>> +#define MAX5970_FAST2SLOW_RATIO			200
>> +
>> +#define MAX5970_REG_STATUS0				0x31
>> +#define  MAX5970_CB_IFAULTF(ch)			(1 << (ch))
>> +#define  MAX5970_CB_IFAULTS(ch)			(1 << ((ch) + 4))
>> +
>> +#define MAX5970_REG_STATUS1				0x32
>> +#define  STATUS1_PROT_MASK				0x3
>> +#define  STATUS1_PROT(reg) \
>> +	(((reg) >> 6) & STATUS1_PROT_MASK)
>> +#define  STATUS1_PROT_SHUTDOWN			0
>> +#define  STATUS1_PROT_CLEAR_PG			1
>> +#define  STATUS1_PROT_ALERT_ONLY		2
>> +
>> +#define MAX5970_REG_STATUS2				0x33
>> +#define  MAX5970_IRNG_MASK				0x3
>> +#define  MAX5970_IRNG(reg, ch)	\
>> +						(((reg) >> ((ch) * 2)) & MAX5970_IRNG_MASK)
>> +
>> +#define MAX5970_REG_STATUS3				0x34
>> +#define  MAX5970_STATUS3_ALERT			BIT(4)
>> +#define  MAX5970_STATUS3_PG(ch)			BIT(ch)
>> +
>> +#define MAX5970_REG_FAULT0				0x35
>> +#define  UV_STATUS_WARN(ch)				BIT(ch)
>> +#define  UV_STATUS_CRIT(ch)				BIT(ch + 4)
>> +
>> +#define MAX5970_REG_FAULT1				0x36
>> +#define  OV_STATUS_WARN(ch)				BIT(ch)
>> +#define  OV_STATUS_CRIT(ch)				BIT(ch + 4)
>> +
>> +#define MAX5970_REG_FAULT2				0x37
>> +#define  OC_STATUS_WARN(ch)				BIT(ch)
>> +
>> +#define MAX5970_REG_CHXEN				0x3b
>> +#define  CHXEN(ch)						(3 << (ch * 2))
>> +
>> +#define MAX5970_REG_LED_FLASH			0x43
>> +
>> +#define MAX_REGISTERS					0x49
>> +#define ADC_MASK						0x3FF
>> +
>> +struct max597x_data {
>> +	struct device *dev;
>> +	int irq;
>> +	int num_switches;
>> +	struct regmap *regmap;
>> +	/* Chip specific parameters needed by regulator & iio cells */
>> +	u32 irng[MAX5970_NUM_SWITCHES];
>> +	u32 mon_rng[MAX5970_NUM_SWITCHES];
>> +	u32 shunt_micro_ohms[MAX5970_NUM_SWITCHES];
>> +};
>> +
>> +#endif
>