Re: [PATCH v2 2/5] mfd: max597x: Add support for MAX5970 and MAX5978

From: Lee Jones
Date: Mon Aug 08 2022 - 09:55:30 EST

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On Thu, 07 Jul 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 it's own regulator supply nammed 'vss1-supply' and

Nit "its" and "supplies"

> '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' to be present in

"property to be ..."

> the devicetree to properly calculate current related values.

Drop "the" and it's "Device Tree"

> You must specify compatible devictree layout:

This doesn't need to be in the commit message.

Save it for the documentation.

> regulator@3a {
> reg = <0x3a>;
> vss1-supply = <&p3v3>;
> compatible = "maxim,max5978";
>
> ...
>
> regulators {
> sw0_ref: SW0 {
> regulator-compatible = "SW0";
> shunt-resistor-micro-ohms = <12000>;
> ...
> }
> }
> }
>
> 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>
> Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>

What is the relationship between all of these people?

What did each of them provide to the patch?

> ---
> drivers/mfd/Kconfig | 12 ++++
> drivers/mfd/Makefile | 2 +
> drivers/mfd/max597x.c | 109 ++++++++++++++++++++++++++++++++++++
> include/linux/mfd/max597x.h | 100 +++++++++++++++++++++++++++++++++
> 4 files changed, 223 insertions(+)
> create mode 100644 drivers/mfd/max597x.c
> create mode 100644 include/linux/mfd/max597x.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 3b59456f5545..2422ae155118 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"

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.

LEDs

> +
> config MFD_CS47L15
> bool "Cirrus Logic CS47L15"
> select PINCTRL_CS47L15
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 858cacf659d6..f5f46b86401f 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -95,6 +95,8 @@ obj-$(CONFIG_MFD_MADERA) += madera.o
> obj-$(CONFIG_MFD_MADERA_I2C) += madera-i2c.o
> obj-$(CONFIG_MFD_MADERA_SPI) += madera-spi.o
>
> +obj-$(CONFIG_MFD_MAX597X) += max597x.o

Why don't you put it next to the existing MAX entries?

> obj-$(CONFIG_TPS6105X) += tps6105x.o
> obj-$(CONFIG_TPS65010) += tps65010.o
> obj-$(CONFIG_TPS6507X) += tps6507x.o
> diff --git a/drivers/mfd/max597x.c b/drivers/mfd/max597x.c
> new file mode 100644
> index 000000000000..b2450e64d3eb
> --- /dev/null
> +++ b/drivers/mfd/max597x.c
> @@ -0,0 +1,109 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Device driver for regulators in MAX5970 and MAX5978 IC

This is not a regulator driver.

Please state what the 2 devices are.

> + * Copyright (c) 2022 9elements GmbH
> + *
> + * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/i2c.h>
> +#include <linux/mfd/core.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/machine.h>
> +#include <linux/regulator/of_regulator.h>
> +#include <linux/version.h>
> +#include <linux/mfd/max597x.h>

Alphabetical.

Also, are you sure *all* of these are needed?

> +static const struct regmap_config max597x_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = MAX_REGISTERS,
> +};
> +
> +static const struct mfd_cell max597x_devs[] = {

max597x_cells

> + {
> + .name = "max597x-regulator",
> + },
> + {
> + .name = "max597x-iio",
> + },
> + {
> + .name = "max597x-led",
> + },

Like this please:

{ .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 *max597x;

"_ddata *ddata"

> + struct regmap *regmap;
> + enum max597x_chip_type chip = id->driver_data;
> +
> + max597x =

No break.

> + devm_kzalloc(&i2c->dev, sizeof(struct max597x_data), GFP_KERNEL);

sizeof(*ddata)

'\n'

> + switch (chip) {
> + case MAX597x_TYPE_MAX5970:
> + max597x->num_switches = 2;
> + break;
> + case MAX597x_TYPE_MAX5978:
> + max597x->num_switches = 1;
> + break;
> + }

Are you planning on expanding the information in .data?

If not, why not put the number of switches in there instead?

> + regmap = devm_regmap_init_i2c(i2c, &max597x_regmap_config);
> + if (IS_ERR(regmap)) {
> + dev_err(&i2c->dev, "No regmap\n");

Is that really what that means?

"Failed to initialise regmap"

> + return -EINVAL;
> + }

'\n'

> + max597x->regmap = regmap;

Why not put the value straight into max597x->regmap instead of
creating a local variable that's only used once?

> + max597x->irq = i2c->irq;
> + max597x->dev = &i2c->dev;

What the reason for saving this?

> + i2c_set_clientdata(i2c, max597x);
> +
> + return devm_mfd_add_devices(max597x->dev, PLATFORM_DEVID_AUTO,
> + max597x_devs, ARRAY_SIZE(max597x_devs),
> + NULL, 0, NULL);
> +}
> +
> +static const struct i2c_device_id max597x_table[] = {
> + {.name = "max5970", MAX597x_TYPE_MAX5970},
> + {.name = "max5978", MAX597x_TYPE_MAX5978},

Spaces after the { and before the } please.

> + {},
> +};
> +

Remove this line.

> +MODULE_DEVICE_TABLE(i2c, max597x_table);
> +
> +static const struct of_device_id max597x_of_match[] = {
> + { .compatible = "maxim,max5970",

Needs to be on the line below.

> + .data = (void *)MAX597x_TYPE_MAX5970
> + },
> + { .compatible = "maxim,max5978",

Line below.

> + .data = (void *)MAX597x_TYPE_MAX5978
> + },
> + {},
> +};
> +

Remove.

> +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),
> + },

Wrong tab spacing. Should line up with the .driver.

> + .probe = max597x_probe,
> +};
> +

Remove.

> +module_i2c_driver(max597x_driver);
> +
> +MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");

This is not a good description.

> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/max597x.h b/include/linux/mfd/max597x.h
> new file mode 100644
> index 000000000000..ac7e9c84d06c
> --- /dev/null
> +++ b/include/linux/mfd/max597x.h
> @@ -0,0 +1,100 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Device driver for regulators in MAX5970 and MAX5978 IC

As above.

> + * Copyright (c) 2022 9elements GmbH
> + *
> + * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
> + */
> +
> +#ifndef _MAX597X_H
> +#define _MAX597X_H

MFD_

> +#include <linux/regmap.h>

device.h

> +#define MAX5970_NUM_SWITCHES 2
> +#define MAX5978_NUM_SWITCHES 1
> +#define MAX597X_NUM_LEDS 4
> +
> +struct max597x_data {

Place this at the bottom of the file.

> + struct device *dev;
> + int irq;
> + int num_switches;
> + struct regmap *regmap;

> + u32 irng[MAX5970_NUM_SWITCHES];
> + u32 mon_rng[MAX5970_NUM_SWITCHES];
> + u32 shunt_micro_ohms[MAX5970_NUM_SWITCHES];

Why are these here?

> +};
> +
> +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))

BIT()?

Same for the macros below.

> +#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) (1 << (ch))
> +#define UV_STATUS_CRIT(ch) (1 << ((ch) + 4))
> +
> +#define MAX5970_REG_FAULT1 0x36
> +#define OV_STATUS_WARN(ch) (1 << (ch))
> +#define OV_STATUS_CRIT(ch) (1 << ((ch) + 4))
> +
> +#define MAX5970_REG_FAULT2 0x37
> +#define OC_STATUS_WARN(ch) (1 << (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
> +
> +#endif /* _MAX597X_H */

--
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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