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

From: Lee Jones
Date: Thu Nov 17 2022 - 05:16:07 EST

On Wed, 16 Nov 2022, Naresh Solanki wrote:

> From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxx>
> Co-developed-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
> Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
> Co-developed-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> ---
> 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?

> 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@xxxxxxxxxxxxx>
> + */
> +
> +#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@xxxxxxxxxxxxx>");
> +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@xxxxxxxxxxxxx>
> + */
> +
> +#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

--
Lee Jones [李琼斯]