Re: [PATCH] hwmon: it87: describe per-chip temperature resources

Benoit Masson
2025-12-26T20:54:57Z

This patch is intended to be part of a series to help with support of
newer IT chipp which have new more dynamic options, and make the
review easier.

This patch is about making the number of:
- temperature limit registers,
- temperature offset registers, and
- temperature-to-PWM mapping slots (per PWM bank)
configurable per chip, instead of hard-coded constants.

for all existing chips in the in-tree driver this patch does not
change behavior because you:
- keep the old defaults (3 temp limits, 3 offsets, “3+3” PWM temp
mapping banks),
- and only prepare per-chip fields without actually changing any
it87_devices[] initialisers yet.

Thanks
Benoit

On Fri, Dec 26, 2025 at 9:30 PM benoit.masson <yahoo@perenite.com> wrote:
>
> Signed-off-by: benoit.masson <yahoo@perenite.com>
> ---
> drivers/hwmon/it87.c | 50 ++++++++++++++++++++++++++++++++------------
> 1 file changed, 37 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
> index e233aafa8856..f9eca0bc02bc 100644
> --- a/drivers/hwmon/it87.c
> +++ b/drivers/hwmon/it87.c
> @@ -54,6 +54,7 @@
> #include <linux/hwmon-vid.h>
> #include <linux/err.h>
> #include <linux/mutex.h>
> +#include <linux/minmax.h>
> #include <linux/sysfs.h>
> #include <linux/string.h>
> #include <linux/dmi.h>
> @@ -279,8 +280,9 @@ static const u8 IT87_REG_AUTO_BASE[] = { 0x60, 0x68, 0x70, 0x78, 0xa0, 0xa8 };
> #define NUM_VIN ARRAY_SIZE(IT87_REG_VIN)
> #define NUM_VIN_LIMIT 8
> #define NUM_TEMP 6
> -#define NUM_TEMP_OFFSET ARRAY_SIZE(IT87_REG_TEMP_OFFSET)
> -#define NUM_TEMP_LIMIT 3
> +#define IT87_TEMP_OFFSET_MAX ARRAY_SIZE(IT87_REG_TEMP_OFFSET)
> +#define IT87_TEMP_LIMIT_DEFAULT 3
> +#define IT87_TEMP_MAP_DEFAULT 3
> #define NUM_FAN ARRAY_SIZE(IT87_REG_FAN)
> #define NUM_FAN_DIV 3
> #define NUM_PWM ARRAY_SIZE(IT87_REG_PWM)
> @@ -290,6 +292,9 @@ struct it87_devices {
> const char *name;
> const char * const model;
> u32 features;
> + u8 num_temp_limit;
> + u8 num_temp_offset;
> + u8 num_temp_map;
> u8 peci_mask;
> u8 old_peci_mask;
> u8 smbus_bitmap; /* SMBus enable bits in extra config register */
> @@ -578,6 +583,9 @@ struct it87_data {
> int sioaddr;
> enum chips type;
> u32 features;
> + u8 num_temp_limit;
> + u8 num_temp_offset;
> + u8 num_temp_map;
> u8 peci_mask;
> u8 old_peci_mask;
>
> @@ -926,12 +934,13 @@ static struct it87_data *it87_update_device(struct device *dev)
> data->temp[i][0] =
> it87_read_value(data, IT87_REG_TEMP(i));
>
> - if (has_temp_offset(data) && i < NUM_TEMP_OFFSET)
> + if (has_temp_offset(data) &&
> + i < data->num_temp_offset)
> data->temp[i][3] =
> it87_read_value(data,
> IT87_REG_TEMP_OFFSET[i]);
>
> - if (i >= NUM_TEMP_LIMIT)
> + if (i >= data->num_temp_limit)
> continue;
>
> data->temp[i][1] =
> @@ -1679,16 +1688,17 @@ static ssize_t show_pwm_temp_map(struct device *dev,
> struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
> struct it87_data *data = it87_update_device(dev);
> int nr = sensor_attr->index;
> + u8 num_map = data->num_temp_map ?: IT87_TEMP_MAP_DEFAULT;
> int map;
>
> if (IS_ERR(data))
> return PTR_ERR(data);
>
> map = data->pwm_temp_map[nr];
> - if (map >= 3)
> + if (map >= num_map)
> map = 0; /* Should never happen */
> - if (nr >= 3) /* pwm channels 3..6 map to temp4..6 */
> - map += 3;
> + if (nr >= num_map) /* pwm channels 3..6 map to temp4..6 */
> + map += num_map;
>
> return sprintf(buf, "%d\n", (int)BIT(map));
> }
> @@ -1700,6 +1710,7 @@ static ssize_t set_pwm_temp_map(struct device *dev,
> struct sensor_device_attribute *sensor_attr = to_sensor_dev_attr(attr);
> struct it87_data *data = dev_get_drvdata(dev);
> int nr = sensor_attr->index;
> + u8 num_map = data->num_temp_map ?: IT87_TEMP_MAP_DEFAULT;
> long val;
> int err;
> u8 reg;
> @@ -1707,8 +1718,8 @@ static ssize_t set_pwm_temp_map(struct device *dev,
> if (kstrtol(buf, 10, &val) < 0)
> return -EINVAL;
>
> - if (nr >= 3)
> - val -= 3;
> + if (nr >= num_map)
> + val -= num_map;
>
> switch (val) {
> case BIT(0):
> @@ -3206,7 +3217,7 @@ static void it87_check_limit_regs(struct it87_data *data)
> if (reg == 0xff)
> it87_write_value(data, IT87_REG_VIN_MIN(i), 0);
> }
> - for (i = 0; i < NUM_TEMP_LIMIT; i++) {
> + for (i = 0; i < data->num_temp_limit; i++) {
> reg = it87_read_value(data, IT87_REG_TEMP_HIGH(i));
> if (reg == 0xff)
> it87_write_value(data, IT87_REG_TEMP_HIGH(i), 127);
> @@ -3399,6 +3410,7 @@ static int it87_probe(struct platform_device *pdev)
> struct resource *res;
> struct device *dev = &pdev->dev;
> struct it87_sio_data *sio_data = dev_get_platdata(dev);
> + const struct it87_devices *chip;
> int enable_pwm_interface;
> struct device *hwmon_dev;
> int err;
> @@ -3421,9 +3433,21 @@ static int it87_probe(struct platform_device *pdev)
> data->type = sio_data->type;
> data->smbus_bitmap = sio_data->smbus_bitmap;
> data->ec_special_config = sio_data->ec_special_config;
> - data->features = it87_devices[sio_data->type].features;
> - data->peci_mask = it87_devices[sio_data->type].peci_mask;
> - data->old_peci_mask = it87_devices[sio_data->type].old_peci_mask;
> + chip = &it87_devices[sio_data->type];
> + data->features = chip->features;
> + data->peci_mask = chip->peci_mask;
> + data->old_peci_mask = chip->old_peci_mask;
> + data->num_temp_limit = chip->num_temp_limit ?
> + chip->num_temp_limit : IT87_TEMP_LIMIT_DEFAULT;
> + if (chip->num_temp_offset)
> + data->num_temp_offset = min(chip->num_temp_offset,
> + (u8)IT87_TEMP_OFFSET_MAX);
> + else if (has_temp_offset(data))
> + data->num_temp_offset = IT87_TEMP_OFFSET_MAX;
> + else
> + data->num_temp_offset = 0;
> + data->num_temp_map = chip->num_temp_map ?
> + chip->num_temp_map : IT87_TEMP_MAP_DEFAULT;
> /*
> * IT8705F Datasheet 0.4.1, 3h == Version G.
> * IT8712F Datasheet 0.9.1, section 8.3.5 indicates 8h == Version J.
> --
> 2.50.1 (Apple Git-155)
>