On Wed, Nov 11, 2020 at 06:20:55PM +0200, alexandru.tach...@analog.com wrote:
> From: Alexandru Tachici <alexandru.tach...@analog.com>
> 
> LTC2992 is a rail-to-rail system monitor that
> measures current, voltage, and power of two supplies.
> 
> Two ADCs simultaneously measure each supply’s current.
> A third ADC monitors the input voltages and four
> auxiliary external voltages.
> 
> Signed-off-by: Alexandru Tachici <alexandru.tach...@analog.com>
> ---
>  Documentation/hwmon/index.rst   |   1 +
>  Documentation/hwmon/ltc2992.rst |  56 +++
>  drivers/hwmon/Kconfig           |  11 +
>  drivers/hwmon/Makefile          |   1 +
>  drivers/hwmon/ltc2992.c         | 818 ++++++++++++++++++++++++++++++++
>  5 files changed, 887 insertions(+)
>  create mode 100644 Documentation/hwmon/ltc2992.rst
>  create mode 100644 drivers/hwmon/ltc2992.c
> 
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index e6b91ab12978..98575a8b1918 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -100,6 +100,7 @@ Hardware Monitoring Kernel Drivers
>     lm95234
>     lm95245
>     lochnagar
> +   ltc2992
>     ltc2945
>     ltc2947
>     ltc2978
> diff --git a/Documentation/hwmon/ltc2992.rst b/Documentation/hwmon/ltc2992.rst
> new file mode 100644
> index 000000000000..46aa1aa84a1a
> --- /dev/null
> +++ b/Documentation/hwmon/ltc2992.rst
> @@ -0,0 +1,56 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver ltc2992
> +=====================
> +
> +Supported chips:
> +  * Linear Technology LTC2992
> +    Prefix: 'ltc2992'
> +    Datasheet: 
> https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2992.pdf
> +
> +Author: Alexandru Tachici <alexandru.tach...@analog.com>
> +
> +
> +Description
> +-----------
> +
> +This driver supports hardware monitoring for Linear Technology LTC2992 power 
> monitor.
> +
> +LTC2992 is a rail-to-rail system monitor that measures current,
> +voltage, and power of two supplies.
> +
> +Two ADCs simultaneously measure each supply’s current. A third ADC monitors
> +the input voltages and four auxiliary external voltages.
> +
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported. Limits are read-write,
> +all other attributes are read-only.
> +
> +in_reset_history     Reset all highest/lowest values.
> +
> +inX_input            Measured voltage.
> +inX_lowest           Minimum measured voltage.
> +inX_highest          Maximum measured voltage.
> +inX_min                      Minimum voltage allowed.
> +inX_max                      Maximum voltage allowed.
> +inX_min_alarm                An undervoltage occurred. Cleared on read.
> +inX_max_alarm                An overvoltage occurred. Cleared on read.
> +
> +currX_input          Measured current.
> +currX_lowest         Minimum measured current.
> +currX_highest                Maximum measured current.
> +currX_min            Minimum current allowed.
> +currX_max            Maximum current allowed.
> +currX_min_alarm              An undercurrent occurred. Cleared on read.
> +currX_max_alarm              An overcurrent occurred. Cleared on read.
> +
> +powerX_input         Measured power.
> +powerX_input_lowest  Minimum measured voltage.
> +powerX_input_highest Maximum measured voltage.
> +powerX_min           Minimum power.
> +powerX_max           Maximum power.
> +powerX_min_alarm     An underpower occurred. Cleared on read.
> +powerX_max_alarm     An overpower occurred. Cleared on read.
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index a850e4f0e0bd..bf9e387270d6 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -858,6 +858,17 @@ config SENSORS_LTC2990
>         This driver can also be built as a module. If so, the module will
>         be called ltc2990.
>  
> +config SENSORS_LTC2992
> +     tristate "Linear Technology LTC2992"
> +     depends on I2C
> +     help
> +       If you say yes here you get support for Linear Technology LTC2992
> +       I2C System Monitor. The LTC2992 measures current, voltage, and
> +       power of two supplies.
> +
> +       This driver can also be built as a module. If so, the module will
> +       be called ltc2992.
> +
>  config SENSORS_LTC4151
>       tristate "Linear Technology LTC4151"
>       depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index 9db2903b61e5..d6172c4807c4 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -118,6 +118,7 @@ obj-$(CONFIG_SENSORS_LTC2947)     += ltc2947-core.o
>  obj-$(CONFIG_SENSORS_LTC2947_I2C) += ltc2947-i2c.o
>  obj-$(CONFIG_SENSORS_LTC2947_SPI) += ltc2947-spi.o
>  obj-$(CONFIG_SENSORS_LTC2990)        += ltc2990.o
> +obj-$(CONFIG_SENSORS_LTC2992)        += ltc2992.o
>  obj-$(CONFIG_SENSORS_LTC4151)        += ltc4151.o
>  obj-$(CONFIG_SENSORS_LTC4215)        += ltc4215.o
>  obj-$(CONFIG_SENSORS_LTC4222)        += ltc4222.o
> diff --git a/drivers/hwmon/ltc2992.c b/drivers/hwmon/ltc2992.c
> new file mode 100644
> index 000000000000..ce679405ac81
> --- /dev/null
> +++ b/drivers/hwmon/ltc2992.c
> @@ -0,0 +1,818 @@
> +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +/*
> + * LTC2992 - Dual Wide Range Power Monitor
> + *
> + * Copyright 2020 Analog Devices Inc.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/bitops.h>
> +#include <linux/bits.h>

You only use BIT(), so a single include should be sufficient.

> +#include <linux/err.h>
> +#include <linux/hwmon.h>
> +#include <linux/hwmon-sysfs.h>

Unnecessary include.

> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>
> +
> +#define LTC2992_CTRLB                        0x01
> +#define LTC2992_FAULT1                       0x03
> +#define LTC2992_POWER1                       0x05
> +#define LTC2992_POWER1_MAX           0x08
> +#define LTC2992_POWER1_MIN           0x0B
> +#define LTC2992_POWER1_MAX_THRESH    0x0E
> +#define LTC2992_POWER1_MIN_THRESH    0x11
> +#define LTC2992_DSENSE1                      0x14
> +#define LTC2992_DSENSE1_MAX          0x16
> +#define LTC2992_DSENSE1_MIN          0x18
> +#define LTC2992_DSENSE1_MAX_THRESH   0x1A
> +#define LTC2992_DSENSE1_MIN_THRESH   0x1C
> +#define LTC2992_SENSE1                       0x1E
> +#define LTC2992_SENSE1_MAX           0x20
> +#define LTC2992_SENSE1_MIN           0x22
> +#define LTC2992_SENSE1_MAX_THRESH    0x24
> +#define LTC2992_SENSE1_MIN_THRESH    0x26
> +#define LTC2992_G1                   0x28
> +#define LTC2992_G1_MAX                       0x2A
> +#define LTC2992_G1_MIN                       0x2C
> +#define LTC2992_G1_MAX_THRESH                0x2E
> +#define LTC2992_G1_MIN_THRESH                0x30
> +#define LTC2992_FAULT2                       0x35
> +#define LTC2992_G2                   0x5A
> +#define LTC2992_G2_MAX                       0x5C
> +#define LTC2992_G2_MIN                       0x5E
> +#define LTC2992_G2_MAX_THRESH                0x60
> +#define LTC2992_G2_MIN_THRESH                0x62
> +#define LTC2992_G3                   0x64
> +#define LTC2992_G3_MAX                       0x66
> +#define LTC2992_G3_MIN                       0x68
> +#define LTC2992_G3_MAX_THRESH                0x6A
> +#define LTC2992_G3_MIN_THRESH                0x6C
> +#define LTC2992_G4                   0x6E
> +#define LTC2992_G4_MAX                       0x70
> +#define LTC2992_G4_MIN                       0x72
> +#define LTC2992_G4_MAX_THRESH                0x74
> +#define LTC2992_G4_MIN_THRESH                0x76
> +#define LTC2992_FAULT3                       0x92
> +
> +#define LTC2992_POWER(x)             (LTC2992_POWER1 + ((x) * 0x32))
> +#define LTC2992_POWER_MAX(x)         (LTC2992_POWER1_MAX + ((x) * 0x32))
> +#define LTC2992_POWER_MIN(x)         (LTC2992_POWER1_MIN + ((x) * 0x32))
> +#define LTC2992_POWER_MAX_THRESH(x)  (LTC2992_POWER1_MAX_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_POWER_MIN_THRESH(x)  (LTC2992_POWER1_MIN_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_DSENSE(x)            (LTC2992_DSENSE1 + ((x) * 0x32))
> +#define LTC2992_DSENSE_MAX(x)                (LTC2992_DSENSE1_MAX + ((x) * 
> 0x32))
> +#define LTC2992_DSENSE_MIN(x)                (LTC2992_DSENSE1_MIN + ((x) * 
> 0x32))
> +#define LTC2992_DSENSE_MAX_THRESH(x) (LTC2992_DSENSE1_MAX_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_DSENSE_MIN_THRESH(x) (LTC2992_DSENSE1_MIN_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_SENSE(x)             (LTC2992_SENSE1 + ((x) * 0x32))
> +#define LTC2992_SENSE_MAX(x)         (LTC2992_SENSE1_MAX + ((x) * 0x32))
> +#define LTC2992_SENSE_MIN(x)         (LTC2992_SENSE1_MIN + ((x) * 0x32))
> +#define LTC2992_SENSE_MAX_THRESH(x)  (LTC2992_SENSE1_MAX_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_SENSE_MIN_THRESH(x)  (LTC2992_SENSE1_MIN_THRESH + ((x) * 
> 0x32))
> +#define LTC2992_POWER_FAULT(x)               (LTC2992_FAULT1 + ((x) * 0x32))
> +#define LTC2992_SENSE_FAULT(x)               (LTC2992_FAULT1 + ((x) * 0x32))
> +#define LTC2992_DSENSE_FAULT(x)              (LTC2992_FAULT1 + ((x) * 0x32))
> +
> +/* CTRLB register bitfields */
> +#define LTC2992_RESET_HISTORY                BIT(3)
> +
> +/* FAULT1 FAULT2 registers common bitfields */
> +#define LTC2992_POWER_FAULT_MSK(x)   (BIT(6) << (x))
> +#define LTC2992_DSENSE_FAULT_MSK(x)  (BIT(4) << (x))
> +#define LTC2992_SENSE_FAULT_MSK(x)   (BIT(2) << (x))
> +
> +/* FAULT1 bitfields */
> +#define LTC2992_GPIO1_FAULT_MSK(x)   (BIT(0) << (x))
> +
> +/* FAULT2 bitfields */
> +#define LTC2992_GPIO2_FAULT_MSK(x)   (BIT(0) << (x))
> +
> +/* FAULT3 bitfields */
> +#define LTC2992_GPIO3_FAULT_MSK(x)   (BIT(6) << (x))
> +#define LTC2992_GPIO4_FAULT_MSK(x)   (BIT(4) << (x))
> +
> +#define LTC2992_IADC_NANOV_LSB               12500
> +#define LTC2992_VADC_UV_LSB          25000
> +#define LTC2992_VADC_GPIO_UV_LSB     500
> +
> +struct ltc2992_state {
> +     struct i2c_client               *client;
> +     struct regmap                   *regmap;
> +     u32                             r_sense_uohm[2];
> +};
> +
> +struct ltc2992_gpio_regs {
> +     u8      data;
> +     u8      max;
> +     u8      min;
> +     u8      max_thresh;
> +     u8      min_thresh;
> +     u8      alarm;
> +     u8      min_alarm_msk;
> +     u8      max_alarm_msk;
> +};
> +
> +static const struct ltc2992_gpio_regs ltc2992_gpio_addr_map[] = {
> +     {
> +             .data = LTC2992_G1,
> +             .max = LTC2992_G1_MAX,
> +             .min = LTC2992_G1_MIN,
> +             .max_thresh = LTC2992_G1_MAX_THRESH,
> +             .min_thresh = LTC2992_G1_MIN_THRESH,
> +             .alarm = LTC2992_FAULT1,
> +             .min_alarm_msk = LTC2992_GPIO1_FAULT_MSK(0),
> +             .max_alarm_msk = LTC2992_GPIO1_FAULT_MSK(1),
> +     },
> +     {
> +             .data = LTC2992_G2,
> +             .max = LTC2992_G2_MAX,
> +             .min = LTC2992_G2_MIN,
> +             .max_thresh = LTC2992_G2_MAX_THRESH,
> +             .min_thresh = LTC2992_G2_MIN_THRESH,
> +             .alarm = LTC2992_FAULT2,
> +             .min_alarm_msk = LTC2992_GPIO2_FAULT_MSK(0),
> +             .max_alarm_msk = LTC2992_GPIO2_FAULT_MSK(1),
> +     },
> +     {
> +             .data = LTC2992_G3,
> +             .max = LTC2992_G3_MAX,
> +             .min = LTC2992_G3_MIN,
> +             .max_thresh = LTC2992_G3_MAX_THRESH,
> +             .min_thresh = LTC2992_G3_MIN_THRESH,
> +             .alarm = LTC2992_FAULT3,
> +             .min_alarm_msk = LTC2992_GPIO3_FAULT_MSK(0),
> +             .max_alarm_msk = LTC2992_GPIO3_FAULT_MSK(1),
> +     },
> +     {
> +             .data = LTC2992_G4,
> +             .max = LTC2992_G4_MAX,
> +             .min = LTC2992_G4_MIN,
> +             .max_thresh = LTC2992_G4_MAX_THRESH,
> +             .min_thresh = LTC2992_G4_MIN_THRESH,
> +             .alarm = LTC2992_FAULT3,
> +             .min_alarm_msk = LTC2992_GPIO4_FAULT_MSK(0),
> +             .max_alarm_msk = LTC2992_GPIO4_FAULT_MSK(1),
> +     },
> +};
> +
> +static int ltc2992_read_reg(struct ltc2992_state *st, u8 addr, const u8 
> reg_len)
> +{
> +     u8 regvals[4];
> +     int ret;
> +     int val;
> +     int i;
> +
> +     ret = regmap_bulk_read(st->regmap, addr, regvals, reg_len);
> +     if (ret < 0)
> +             return ret;
> +
> +     val = 0;
> +     for (i = 0; i < reg_len; i++)
> +             val |= regvals[reg_len - i - 1] << (i * 8);
> +
> +     return val;
> +}
> +
> +static int ltc2992_write_reg(struct ltc2992_state *st, u8 addr, const u8 
> reg_len, u32 val)
> +{
> +     u8 regvals[4];
> +     int i;
> +
> +     for (i = 0; i < reg_len; i++)
> +             regvals[reg_len - i - 1] = (val >> (i * 8)) & 0xFF;
> +
> +     return regmap_bulk_write(st->regmap, addr, regvals, reg_len);
> +}
> +
> +static umode_t ltc2992_is_visible(const void *data, enum hwmon_sensor_types 
> type, u32 attr,
> +                               int channel)
> +{
> +     const struct ltc2992_state *st = data;
> +
> +     switch (type) {
> +     case hwmon_chip:
> +             switch (attr) {
> +             case hwmon_chip_in_reset_history:
> +                     return 0200;
> +             }
> +             break;
> +     case hwmon_in:
> +             switch (attr) {
> +             case hwmon_in_input:
> +             case hwmon_in_lowest:
> +             case hwmon_in_highest:
> +             case hwmon_in_min_alarm:
> +             case hwmon_in_max_alarm:
> +                     return 0444;
> +             case hwmon_in_min:
> +             case hwmon_in_max:
> +                     return 0644;
> +             }
> +             break;
> +     case hwmon_curr:
> +             switch (attr) {
> +             case hwmon_curr_input:
> +             case hwmon_curr_lowest:
> +             case hwmon_curr_highest:
> +             case hwmon_curr_min_alarm:
> +             case hwmon_curr_max_alarm:
> +                     if (st->r_sense_uohm[channel])
> +                             return 0444;
> +                     break;
> +             case hwmon_curr_min:
> +             case hwmon_curr_max:
> +                     if (st->r_sense_uohm[channel])
> +                             return 0644;
> +                     break;
> +             }
> +             break;
> +     case hwmon_power:
> +             switch (attr) {
> +             case hwmon_power_input:
> +             case hwmon_power_input_lowest:
> +             case hwmon_power_input_highest:
> +             case hwmon_power_min_alarm:
> +             case hwmon_power_max_alarm:
> +                     if (st->r_sense_uohm[channel])
> +                             return 0444;
> +                     break;
> +             case hwmon_power_min:
> +             case hwmon_power_max:
> +                     if (st->r_sense_uohm[channel])
> +                             return 0644;
> +                     break;
> +             }
> +             break;
> +     default:
> +             break;
> +     }
> +
> +     return 0;
> +}
> +
> +static int ltc2992_get_voltage(struct ltc2992_state *st, u32 reg, u32 scale, 
> long *val)
> +{
> +     int reg_val;
> +
> +     reg_val = ltc2992_read_reg(st, reg, 2);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     reg_val = reg_val >> 4;
> +     *val = DIV_ROUND_CLOSEST(reg_val * scale, 1000);
> +
> +     return 0;
> +}
> +
> +static int ltc2992_set_voltage(struct ltc2992_state *st, u32 reg, u32 scale, 
> long val)
> +{
> +     val = DIV_ROUND_CLOSEST(val * 1000, scale);
> +     val = val << 4;
> +
> +     return ltc2992_write_reg(st, reg, 2, val);
> +}
> +
> +static int ltc2992_read_gpio_alarm(struct ltc2992_state *st, int nr_gpio, 
> u32 attr, long *val)
> +{
> +     int reg_val;
> +     u32 mask;
> +
> +     if (attr == hwmon_in_max_alarm)
> +             mask = ltc2992_gpio_addr_map[nr_gpio].max_alarm_msk;
> +     else
> +             mask = ltc2992_gpio_addr_map[nr_gpio].min_alarm_msk;
> +
> +     reg_val = ltc2992_read_reg(st, ltc2992_gpio_addr_map[nr_gpio].alarm, 1);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     *val = !!(reg_val & mask);
> +     reg_val &= ~mask;
> +
> +     return ltc2992_write_reg(st, ltc2992_gpio_addr_map[nr_gpio].alarm, 1, 
> reg_val);
> +}
> +
> +static int ltc2992_read_gpios_in(struct device *dev, u32 attr, int nr_gpio, 
> long *val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     switch (attr) {
> +     case hwmon_in_input:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].data;
> +             break;
> +     case hwmon_in_lowest:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].min;
> +             break;
> +     case hwmon_in_highest:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].max;
> +             break;
> +     case hwmon_in_min:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].min_thresh;
> +             break;
> +     case hwmon_in_max:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].max_thresh;
> +             break;
> +     case hwmon_in_min_alarm:
> +     case hwmon_in_max_alarm:
> +             return ltc2992_read_gpio_alarm(st, nr_gpio, attr, val);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_get_voltage(st, reg, LTC2992_VADC_GPIO_UV_LSB, val);
> +}
> +
> +static int ltc2992_read_in_alarm(struct ltc2992_state *st, int channel, long 
> *val, u32 attr)
> +{
> +     u32 reg_val;
> +     u32 mask;
> +
> +     if (attr == hwmon_in_max_alarm)
> +             mask = LTC2992_SENSE_FAULT_MSK(1);
> +     else
> +             mask = LTC2992_SENSE_FAULT_MSK(0);
> +
> +     reg_val = ltc2992_read_reg(st, LTC2992_SENSE_FAULT(channel), 1);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     *val = !!(reg_val & mask);
> +     reg_val &= ~mask;
> +
> +     return ltc2992_write_reg(st, LTC2992_SENSE_FAULT(channel), 1, reg_val);
> +}
> +
> +static int ltc2992_read_in(struct device *dev, u32 attr, int channel, long 
> *val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     if (channel > 1)
> +             return ltc2992_read_gpios_in(dev, attr, channel - 2, val);
> +
> +     switch (attr) {
> +     case hwmon_in_input:
> +             reg = LTC2992_SENSE(channel);
> +             break;
> +     case hwmon_in_lowest:
> +             reg = LTC2992_SENSE_MIN(channel);
> +             break;
> +     case hwmon_in_highest:
> +             reg = LTC2992_SENSE_MAX(channel);
> +             break;
> +     case hwmon_in_min:
> +             reg = LTC2992_SENSE_MIN_THRESH(channel);
> +             break;
> +     case hwmon_in_max:
> +             reg = LTC2992_SENSE_MAX_THRESH(channel);
> +             break;
> +     case hwmon_in_min_alarm:
> +     case hwmon_in_max_alarm:
> +             return ltc2992_read_in_alarm(st, channel, val, attr);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_get_voltage(st, reg, LTC2992_VADC_UV_LSB, val);
> +}
> +
> +static int ltc2992_get_current(struct ltc2992_state *st, u32 reg, u32 
> channel, long *val)
> +{
> +     u32 reg_val;
> +
> +     reg_val = ltc2992_read_reg(st, reg, 2);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     reg_val = reg_val >> 4;
> +     *val = DIV_ROUND_CLOSEST(reg_val * LTC2992_IADC_NANOV_LSB, 
> st->r_sense_uohm[channel]);
> +
> +     return 0;
> +}
> +
> +static int ltc2992_set_current(struct ltc2992_state *st, u32 reg, u32 
> channel, long val)
> +{
> +     u32 reg_val;
> +
> +     reg_val = DIV_ROUND_CLOSEST(val * st->r_sense_uohm[channel], 
> LTC2992_IADC_NANOV_LSB);
> +     reg_val = reg_val << 4;
> +
> +     return ltc2992_write_reg(st, reg, 2, reg_val);
> +}
> +
> +static int ltc2992_read_curr_alarm(struct ltc2992_state *st, int channel, 
> long *val, u32 attr)
> +{
> +     u32 reg_val;
> +     u32 mask;
> +
> +     if (attr == hwmon_curr_max_alarm)
> +             mask = LTC2992_DSENSE_FAULT_MSK(1);
> +     else
> +             mask = LTC2992_DSENSE_FAULT_MSK(0);
> +
> +     reg_val = ltc2992_read_reg(st, LTC2992_DSENSE_FAULT(channel), 1);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     *val = !!(reg_val & mask);
> +
> +     reg_val &= ~mask;
> +     return ltc2992_write_reg(st, LTC2992_DSENSE_FAULT(channel), 1, reg_val);
> +}
> +
> +static int ltc2992_read_curr(struct device *dev, u32 attr, int channel, long 
> *val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     switch (attr) {
> +     case hwmon_curr_input:
> +             reg = LTC2992_DSENSE(channel);
> +             break;
> +     case hwmon_curr_lowest:
> +             reg = LTC2992_DSENSE_MIN(channel);
> +             break;
> +     case hwmon_curr_highest:
> +             reg = LTC2992_DSENSE_MAX(channel);
> +             break;
> +     case hwmon_curr_min:
> +             reg = LTC2992_DSENSE_MIN_THRESH(channel);
> +             break;
> +     case hwmon_curr_max:
> +             reg = LTC2992_DSENSE_MAX_THRESH(channel);
> +             break;
> +     case hwmon_curr_min_alarm:
> +     case hwmon_curr_max_alarm:
> +             return ltc2992_read_curr_alarm(st, channel, val, attr);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_get_current(st, reg, channel, val);
> +}
> +
> +static int ltc2992_get_power(struct ltc2992_state *st, u32 reg, u32 channel, 
> long *val)
> +{
> +     u32 reg_val;
> +
> +     reg_val = ltc2992_read_reg(st, reg, 3);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     *val = mul_u64_u32_div(reg_val, LTC2992_VADC_UV_LSB * 
> LTC2992_IADC_NANOV_LSB,
> +                            st->r_sense_uohm[channel] * 1000);
> +
> +     return 0;
> +}
> +
> +static int ltc2992_set_power(struct ltc2992_state *st, u32 reg, u32 channel, 
> long val)
> +{
> +     u32 reg_val;
> +
> +     reg_val = mul_u64_u32_div(val, st->r_sense_uohm[channel] * 1000,
> +                               LTC2992_VADC_UV_LSB * LTC2992_IADC_NANOV_LSB);
> +
> +     return ltc2992_write_reg(st, reg, 3, reg_val);
> +}
> +
> +static int ltc2992_read_power_alarm(struct ltc2992_state *st, int channel, 
> long *val, u32 attr)
> +{
> +     u32 reg_val;
> +     u32 mask;
> +
> +     if (attr == hwmon_power_max_alarm)
> +             mask = LTC2992_POWER_FAULT_MSK(1);
> +     else
> +             mask = LTC2992_POWER_FAULT_MSK(0);
> +
> +     reg_val = ltc2992_read_reg(st, LTC2992_POWER_FAULT(channel), 1);
> +     if (reg_val < 0)
> +             return reg_val;
> +
> +     *val = !!(reg_val & mask);
> +     reg_val &= ~mask;
> +
> +     return ltc2992_write_reg(st, LTC2992_POWER_FAULT(channel), 1, reg_val);
> +}
> +
> +static int ltc2992_read_power(struct device *dev, u32 attr, int channel, 
> long *val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     switch (attr) {
> +     case hwmon_power_input:
> +             reg = LTC2992_POWER(channel);
> +             break;
> +     case hwmon_power_input_lowest:
> +             reg = LTC2992_POWER_MIN(channel);
> +             break;
> +     case hwmon_power_input_highest:
> +             reg = LTC2992_POWER_MAX(channel);
> +             break;
> +     case hwmon_power_min:
> +             reg = LTC2992_POWER_MIN_THRESH(channel);
> +             break;
> +     case hwmon_power_max:
> +             reg = LTC2992_POWER_MAX_THRESH(channel);
> +             break;
> +     case hwmon_power_min_alarm:
> +     case hwmon_power_max_alarm:
> +             return ltc2992_read_power_alarm(st, channel, val, attr);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_get_power(st, reg, channel, val);
> +}
> +
> +static int ltc2992_read(struct device *dev, enum hwmon_sensor_types type, 
> u32 attr, int channel,
> +                     long *val)
> +{
> +     switch (type) {
> +     case hwmon_in:
> +             return ltc2992_read_in(dev, attr, channel, val);
> +     case hwmon_curr:
> +             return ltc2992_read_curr(dev, attr, channel, val);
> +     case hwmon_power:
> +             return ltc2992_read_power(dev, attr, channel, val);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +}
> +
> +static int ltc2992_write_curr(struct device *dev, u32 attr, int channel, 
> long val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     switch (attr) {
> +     case hwmon_curr_min:
> +             reg = LTC2992_DSENSE_MIN_THRESH(channel);
> +             break;
> +     case hwmon_curr_max:
> +             reg = LTC2992_DSENSE_MAX_THRESH(channel);
> +             break;
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_set_current(st, reg, channel, val);
> +}
> +
> +static int ltc2992_write_gpios_in(struct device *dev, u32 attr, int nr_gpio, 
> long val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg;
> +
> +     switch (attr) {
> +     case hwmon_in_min:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].min_thresh;
> +             break;
> +     case hwmon_in_max:
> +             reg = ltc2992_gpio_addr_map[nr_gpio].max_thresh;
> +             break;
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_set_voltage(st, reg, LTC2992_VADC_GPIO_UV_LSB, val);
> +}
> +
> +static int ltc2992_write_in(struct device *dev, u32 attr, int channel, long 
> val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg = 0;

Unnecessary initialization.

> +
> +     if (channel > 1)
> +             return ltc2992_write_gpios_in(dev, attr, channel - 2, val);
> +
> +     switch (attr) {
> +     case hwmon_in_min:
> +             reg = LTC2992_SENSE_MIN_THRESH(channel);
> +             break;
> +     case hwmon_in_max:
> +             reg = LTC2992_SENSE_MAX_THRESH(channel);
> +             break;
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_set_voltage(st, reg, LTC2992_VADC_UV_LSB, val);
> +}
> +
> +static int ltc2992_write_power(struct device *dev, u32 attr, int channel, 
> long val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +     u32 reg = 0;

Unnecessary initialization.

> +
> +     switch (attr) {
> +     case hwmon_power_min:
> +             reg = LTC2992_POWER_MIN_THRESH(channel);
> +             break;
> +     case hwmon_power_max:
> +             reg = LTC2992_POWER_MAX_THRESH(channel);
> +             break;
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +
> +     return ltc2992_set_power(st, reg, channel, val);
> +}
> +
> +static int ltc2992_write_chip(struct device *dev, u32 attr, int channel, 
> long val)
> +{
> +     struct ltc2992_state *st = dev_get_drvdata(dev);
> +
> +     switch (attr) {
> +     case hwmon_chip_in_reset_history:
> +             return regmap_update_bits(st->regmap, LTC2992_CTRLB, 
> LTC2992_RESET_HISTORY,
> +                                       LTC2992_RESET_HISTORY);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +}
> +
> +static int ltc2992_write(struct device *dev, enum hwmon_sensor_types type, 
> u32 attr, int channel,
> +                      long val)
> +{
> +     switch (type) {
> +     case hwmon_chip:
> +             return ltc2992_write_chip(dev, attr, channel, val);
> +     case hwmon_in:
> +             return ltc2992_write_in(dev, attr, channel, val);
> +     case hwmon_curr:
> +             return ltc2992_write_curr(dev, attr, channel, val);
> +     case hwmon_power:
> +             return ltc2992_write_power(dev, attr, channel, val);
> +     default:
> +             return -EOPNOTSUPP;
> +     }
> +}
> +
> +static const struct hwmon_ops ltc2992_hwmon_ops = {
> +     .is_visible = ltc2992_is_visible,
> +     .read = ltc2992_read,
> +     .write = ltc2992_write,
> +};
> +
> +static const u32 ltc2992_chip_config[] = {
> +     HWMON_C_IN_RESET_HISTORY,
> +     0
> +};
> +
> +static const struct hwmon_channel_info ltc2992_chip = {
> +     .type = hwmon_chip,
> +     .config = ltc2992_chip_config,
> +};
> +
> +static const u32 ltc2992_in_config[] = {
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     HWMON_I_INPUT | HWMON_I_LOWEST | HWMON_I_HIGHEST | HWMON_I_MIN | 
> HWMON_I_MAX |
> +     HWMON_I_MIN_ALARM | HWMON_I_MAX_ALARM,
> +     0
> +};
> +
> +static const struct hwmon_channel_info ltc2992_in = {
> +     .type = hwmon_in,
> +     .config = ltc2992_in_config,
> +};
> +
> +static const u32 ltc2992_curr_config[] = {
> +     HWMON_C_INPUT | HWMON_C_LOWEST | HWMON_C_HIGHEST | HWMON_C_MIN | 
> HWMON_C_MAX |
> +     HWMON_C_MIN_ALARM | HWMON_C_MAX_ALARM,
> +     HWMON_C_INPUT | HWMON_C_LOWEST | HWMON_C_HIGHEST | HWMON_C_MIN | 
> HWMON_C_MAX |
> +     HWMON_C_MIN_ALARM | HWMON_C_MAX_ALARM,
> +     0
> +};
> +
> +static const struct hwmon_channel_info ltc2992_curr = {
> +     .type = hwmon_curr,
> +     .config = ltc2992_curr_config,
> +};
> +
> +static const u32 ltc2992_power_config[] = {
> +     HWMON_P_INPUT | HWMON_P_INPUT_LOWEST | HWMON_P_INPUT_HIGHEST | 
> HWMON_P_MIN | HWMON_P_MAX |
> +     HWMON_P_MIN_ALARM | HWMON_P_MAX_ALARM,
> +     HWMON_P_INPUT | HWMON_P_INPUT_LOWEST | HWMON_P_INPUT_HIGHEST | 
> HWMON_P_MIN | HWMON_P_MAX |
> +     HWMON_P_MIN_ALARM | HWMON_P_MAX_ALARM,
> +     0
> +};
> +
> +static const struct hwmon_channel_info ltc2992_power = {
> +     .type = hwmon_power,
> +     .config = ltc2992_power_config,
> +};
> +
> +static const struct hwmon_channel_info *ltc2992_info[] = {
> +     &ltc2992_chip,
> +     &ltc2992_in,
> +     &ltc2992_curr,
> +     &ltc2992_power,
> +     NULL
> +};
> +
> +static const struct hwmon_chip_info ltc2992_chip_info = {
> +     .ops = &ltc2992_hwmon_ops,
> +     .info = ltc2992_info,
> +};
> +
> +static const struct regmap_config ltc2992_regmap_config = {
> +     .reg_bits = 8,
> +     .val_bits = 8,
> +     .max_register = 0xE8,
> +};
> +
> +static int ltc2992_parse_dt(struct ltc2992_state *st)
> +{
> +     struct fwnode_handle *fwnode;
> +     struct fwnode_handle *child;
> +     u32 addr;
> +     u32 val;
> +     int ret;
> +
> +     fwnode = dev_fwnode(&st->client->dev);
> +
> +     fwnode_for_each_available_child_node(fwnode, child) {
> +             ret = fwnode_property_read_u32(child, "reg", &addr);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (addr > 1)
> +                     return -EINVAL;
> +
> +             ret = fwnode_property_read_u32(child, 
> "shunt-resistor-micro-ohms", &val);
> +             if (!ret)
> +                     st->r_sense_uohm[addr] = val;
> +     }
> +
> +     return 0;
> +}
> +
> +static int ltc2992_i2c_probe(struct i2c_client *client, const struct 
> i2c_device_id *id)
> +{
> +     struct device *hwmon_dev;
> +     struct ltc2992_state *st;
> +     int ret;
> +
> +     if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
> +             return -ENODEV;

This shuld be unnecesssary. It only really makes sense if there are direct
i2c reads and for special functions like reading block data.

> +
> +     st = devm_kzalloc(&client->dev, sizeof(*st), GFP_KERNEL);
> +     if (!st)
> +             return -ENOMEM;
> +
> +     st->client = client;
> +     st->regmap = devm_regmap_init_i2c(client, &ltc2992_regmap_config);
> +     if (IS_ERR(st->regmap))
> +             return PTR_ERR(st->regmap);
> +
> +     ret = ltc2992_parse_dt(st);
> +     if (ret < 0)
> +             return ret;
> +
> +     hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, 
> client->name, st,
> +                                                      &ltc2992_chip_info, 
> NULL);
> +
> +     return PTR_ERR_OR_ZERO(hwmon_dev);
> +}
> +
> +static const struct of_device_id ltc2992_of_match[] = {
> +     { .compatible = "adi,ltc2992" },
> +     { }
> +};
> +MODULE_DEVICE_TABLE(of, ltc2992_of_match);
> +
> +static const struct i2c_device_id ltc2992_i2c_id[] = {
> +     {"ltc2992", 0},
> +     {}
> +};
> +MODULE_DEVICE_TABLE(i2c, ltc2992_i2c_id);
> +
> +static struct i2c_driver ltc2992_i2c_driver = {
> +     .driver = {
> +             .name = "ltc2992",
> +             .of_match_table = ltc2992_of_match,
> +     },
> +     .probe    = ltc2992_i2c_probe,
> +     .id_table = ltc2992_i2c_id,
> +};
> +
> +module_i2c_driver(ltc2992_i2c_driver);
> +
> +MODULE_AUTHOR("Alexandru Tachici <alexandru.tach...@analog.com>");
> +MODULE_DESCRIPTION("Hwmon driver for Linear Technology 2992");
> +MODULE_LICENSE("Dual BSD/GPL");

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