Re: [PATCH v2 1/5] hwmon: (max31790) Rework to use regmap

["Václav Kubernát" <kubernat@cesnet.cz>]

Hello,

I'm uploading a new version of my patches on max31790. This is a "v3"
patch, but I have mistakenly tagged it as "v2". Hopefully, this is not
a big issue.

Changes:
- I have reintroduced locking. However, I'm not sure if it's enough, I
think, locking needs to happen even when reading, but I'm not sure
- fan_config and fan_dynamics are now saved locally
- I have fixed formatting issues

Václav

út 13. 4. 2021 v 5:02 odesílatel Václav Kubernát <kubernat@cesnet.cz> napsal:
>
> Converting the driver to use regmap makes it more generic. It also makes
> it a lot easier to debug through debugfs.
>
> Signed-off-by: Václav Kubernát <kubernat@cesnet.cz>
> ---
>  drivers/hwmon/Kconfig    |   1 +
>  drivers/hwmon/max31790.c | 254 ++++++++++++++++++++-------------------
>  2 files changed, 133 insertions(+), 122 deletions(-)
>
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 1ecf697d8d99..9f11d036c316 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1095,6 +1095,7 @@ config SENSORS_MAX6697
>  config SENSORS_MAX31790
>         tristate "Maxim MAX31790 sensor chip"
>         depends on I2C
> +       select REGMAP_I2C
>         help
>           If you say yes here you get support for 6-Channel PWM-Output
>           Fan RPM Controller.
> diff --git a/drivers/hwmon/max31790.c b/drivers/hwmon/max31790.c
> index 2c6b333a28e9..e3765ce4444a 100644
> --- a/drivers/hwmon/max31790.c
> +++ b/drivers/hwmon/max31790.c
> @@ -12,6 +12,7 @@
>  #include <linux/init.h>
>  #include <linux/jiffies.h>
>  #include <linux/module.h>
> +#include <linux/regmap.h>
>  #include <linux/slab.h>
>
>  /* MAX31790 registers */
> @@ -46,92 +47,53 @@
>
>  #define NR_CHANNEL                     6
>
> +#define MAX31790_REG_USER_BYTE_67      0x67
> +
> +#define BULK_TO_U16(msb, lsb)          (((msb) << 8) + (lsb))
> +#define U16_MSB(num)                   (((num) & 0xFF00) >> 8)
> +#define U16_LSB(num)                   ((num) & 0x00FF)
> +
> +static const struct regmap_range max31790_ro_range = {
> +       .range_min = MAX31790_REG_TACH_COUNT(0),
> +       .range_max = MAX31790_REG_PWMOUT(0) - 1,
> +};
> +
> +static const struct regmap_access_table max31790_wr_table = {
> +       .no_ranges = &max31790_ro_range,
> +       .n_no_ranges = 1,
> +};
> +
> +static const struct regmap_range max31790_volatile_ranges[] = {
> +       regmap_reg_range(MAX31790_REG_TACH_COUNT(0), MAX31790_REG_TACH_COUNT(12)),
> +       regmap_reg_range(MAX31790_REG_FAN_FAULT_STATUS2, MAX31790_REG_FAN_FAULT_STATUS1),
> +};
> +
> +static const struct regmap_access_table max31790_volatile_table = {
> +       .no_ranges = max31790_volatile_ranges,
> +       .n_no_ranges = 2,
> +       .n_yes_ranges = 0
> +};
> +
> +static const struct regmap_config max31790_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 8,
> +       .reg_stride = 1,
> +       .max_register = MAX31790_REG_USER_BYTE_67,
> +       .wr_table = &max31790_wr_table,
> +       .volatile_table = &max31790_volatile_table
> +};
> +
>  /*
>   * Client data (each client gets its own)
>   */
>  struct max31790_data {
> -       struct i2c_client *client;
> +       struct regmap *regmap;
> +
>         struct mutex update_lock;
> -       bool valid; /* zero until following fields are valid */
> -       unsigned long last_updated; /* in jiffies */
> -
> -       /* register values */
>         u8 fan_config[NR_CHANNEL];
>         u8 fan_dynamics[NR_CHANNEL];
> -       u16 fault_status;
> -       u16 tach[NR_CHANNEL * 2];
> -       u16 pwm[NR_CHANNEL];
> -       u16 target_count[NR_CHANNEL];
>  };
>
> -static struct max31790_data *max31790_update_device(struct device *dev)
> -{
> -       struct max31790_data *data = dev_get_drvdata(dev);
> -       struct i2c_client *client = data->client;
> -       struct max31790_data *ret = data;
> -       int i;
> -       int rv;
> -
> -       mutex_lock(&data->update_lock);
> -
> -       if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
> -               rv = i2c_smbus_read_byte_data(client,
> -                               MAX31790_REG_FAN_FAULT_STATUS1);
> -               if (rv < 0)
> -                       goto abort;
> -               data->fault_status = rv & 0x3F;
> -
> -               rv = i2c_smbus_read_byte_data(client,
> -                               MAX31790_REG_FAN_FAULT_STATUS2);
> -               if (rv < 0)
> -                       goto abort;
> -               data->fault_status |= (rv & 0x3F) << 6;
> -
> -               for (i = 0; i < NR_CHANNEL; i++) {
> -                       rv = i2c_smbus_read_word_swapped(client,
> -                                       MAX31790_REG_TACH_COUNT(i));
> -                       if (rv < 0)
> -                               goto abort;
> -                       data->tach[i] = rv;
> -
> -                       if (data->fan_config[i]
> -                           & MAX31790_FAN_CFG_TACH_INPUT) {
> -                               rv = i2c_smbus_read_word_swapped(client,
> -                                       MAX31790_REG_TACH_COUNT(NR_CHANNEL
> -                                                               + i));
> -                               if (rv < 0)
> -                                       goto abort;
> -                               data->tach[NR_CHANNEL + i] = rv;
> -                       } else {
> -                               rv = i2c_smbus_read_word_swapped(client,
> -                                               MAX31790_REG_PWMOUT(i));
> -                               if (rv < 0)
> -                                       goto abort;
> -                               data->pwm[i] = rv;
> -
> -                               rv = i2c_smbus_read_word_swapped(client,
> -                                               MAX31790_REG_TARGET_COUNT(i));
> -                               if (rv < 0)
> -                                       goto abort;
> -                               data->target_count[i] = rv;
> -                       }
> -               }
> -
> -               data->last_updated = jiffies;
> -               data->valid = true;
> -       }
> -       goto done;
> -
> -abort:
> -       data->valid = false;
> -       ret = ERR_PTR(rv);
> -
> -done:
> -       mutex_unlock(&data->update_lock);
> -
> -       return ret;
> -}
> -
>  static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
>
>  static u8 get_tach_period(u8 fan_dynamics)
> @@ -159,28 +121,75 @@ static u8 bits_for_tach_period(int rpm)
>         return bits;
>  }
>
> +static int read_reg_byte(struct regmap *regmap, u8 reg)
> +{
> +       int rv;
> +       int val;
> +
> +       rv = regmap_read(regmap, reg, &val);
> +       if (rv < 0)
> +               return rv;
> +
> +       return val;
> +}
> +
> +static int read_reg_word(struct regmap *regmap, u8 reg)
> +{
> +       int rv;
> +       u8 val_bulk[2];
> +
> +       rv = regmap_bulk_read(regmap, reg, val_bulk, 2);
> +       if (rv < 0)
> +               return rv;
> +
> +       return BULK_TO_U16(val_bulk[0], val_bulk[1]);
> +}
> +
> +static int write_reg_word(struct regmap *regmap, u8 reg, u16 val)
> +{
> +       u8 bulk_val[2];
> +
> +       bulk_val[0] = U16_MSB(val);
> +       bulk_val[1] = U16_LSB(val);
> +
> +       return regmap_bulk_write(regmap, reg, bulk_val, 2);
> +}
> +
>  static int max31790_read_fan(struct device *dev, u32 attr, int channel,
>                              long *val)
>  {
> -       struct max31790_data *data = max31790_update_device(dev);
> -       int sr, rpm;
> -
> -       if (IS_ERR(data))
> -               return PTR_ERR(data);
> +       struct max31790_data *data = dev_get_drvdata(dev);
> +       struct regmap *regmap = data->regmap;
> +       int tach, fault;
>
>         switch (attr) {
>         case hwmon_fan_input:
> -               sr = get_tach_period(data->fan_dynamics[channel]);
> -               rpm = RPM_FROM_REG(data->tach[channel], sr);
> -               *val = rpm;
> +               tach = read_reg_word(regmap, MAX31790_REG_TACH_COUNT(channel));
> +               if (tach < 0)
> +                       return tach;
> +
> +               *val = RPM_FROM_REG(tach, get_tach_period(data->fan_dynamics[channel]));
>                 return 0;
>         case hwmon_fan_target:
> -               sr = get_tach_period(data->fan_dynamics[channel]);
> -               rpm = RPM_FROM_REG(data->target_count[channel], sr);
> -               *val = rpm;
> +               tach = read_reg_word(regmap, MAX31790_REG_TARGET_COUNT(channel));
> +               if (tach < 0)
> +                       return tach;
> +
> +               *val = RPM_FROM_REG(tach, get_tach_period(data->fan_dynamics[channel]));
>                 return 0;
>         case hwmon_fan_fault:
> -               *val = !!(data->fault_status & (1 << channel));
> +               if (channel > 6)
> +                       fault = read_reg_byte(regmap, MAX31790_REG_FAN_FAULT_STATUS2);
> +               else
> +                       fault = read_reg_byte(regmap, MAX31790_REG_FAN_FAULT_STATUS1);
> +
> +               if (fault < 0)
> +                       return fault;
> +
> +               if (channel > 6)
> +                       *val = !!(fault & (1 << (channel - 6)));
> +               else
> +                       *val = !!(fault & (1 << channel));
>                 return 0;
>         default:
>                 return -EOPNOTSUPP;
> @@ -191,7 +200,7 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
>                               long val)
>  {
>         struct max31790_data *data = dev_get_drvdata(dev);
> -       struct i2c_client *client = data->client;
> +       struct regmap *regmap = data->regmap;
>         int target_count;
>         int err = 0;
>         u8 bits;
> @@ -207,9 +216,10 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
>                         ((data->fan_dynamics[channel] &
>                           ~MAX31790_FAN_DYN_SR_MASK) |
>                          (bits << MAX31790_FAN_DYN_SR_SHIFT));
> -               err = i2c_smbus_write_byte_data(client,
> -                                       MAX31790_REG_FAN_DYNAMICS(channel),
> -                                       data->fan_dynamics[channel]);
> +
> +               err = regmap_write(regmap,
> +                                  MAX31790_REG_FAN_DYNAMICS(channel),
> +                                  data->fan_dynamics[channel]);
>                 if (err < 0)
>                         break;
>
> @@ -217,11 +227,11 @@ static int max31790_write_fan(struct device *dev, u32 attr, int channel,
>                 target_count = RPM_TO_REG(val, sr);
>                 target_count = clamp_val(target_count, 0x1, 0x7FF);
>
> -               data->target_count[channel] = target_count << 5;
> +               target_count = target_count << 5;
>
> -               err = i2c_smbus_write_word_swapped(client,
> -                                       MAX31790_REG_TARGET_COUNT(channel),
> -                                       data->target_count[channel]);
> +               err = write_reg_word(regmap,
> +                                    MAX31790_REG_TARGET_COUNT(channel),
> +                                    target_count);
>                 break;
>         default:
>                 err = -EOPNOTSUPP;
> @@ -258,22 +268,22 @@ static umode_t max31790_fan_is_visible(const void *_data, u32 attr, int channel)
>  static int max31790_read_pwm(struct device *dev, u32 attr, int channel,
>                              long *val)
>  {
> -       struct max31790_data *data = max31790_update_device(dev);
> -       u8 fan_config;
> -
> -       if (IS_ERR(data))
> -               return PTR_ERR(data);
> -
> -       fan_config = data->fan_config[channel];
> +       struct max31790_data *data = dev_get_drvdata(dev);
> +       struct regmap *regmap = data->regmap;
> +       int read;
>
>         switch (attr) {
>         case hwmon_pwm_input:
> -               *val = data->pwm[channel] >> 8;
> +               read = read_reg_word(regmap, MAX31790_REG_PWMOUT(channel));
> +               if (read < 0)
> +                       return read;
> +
> +               *val = read >> 8;
>                 return 0;
>         case hwmon_pwm_enable:
> -               if (fan_config & MAX31790_FAN_CFG_RPM_MODE)
> +               if (data->fan_config[channel] & MAX31790_FAN_CFG_RPM_MODE)
>                         *val = 2;
> -               else if (fan_config & MAX31790_FAN_CFG_TACH_INPUT_EN)
> +               else if (data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN)
>                         *val = 1;
>                 else
>                         *val = 0;
> @@ -287,7 +297,7 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
>                               long val)
>  {
>         struct max31790_data *data = dev_get_drvdata(dev);
> -       struct i2c_client *client = data->client;
> +       struct regmap *regmap = data->regmap;
>         u8 fan_config;
>         int err = 0;
>
> @@ -299,10 +309,7 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
>                         err = -EINVAL;
>                         break;
>                 }
> -               data->pwm[channel] = val << 8;
> -               err = i2c_smbus_write_word_swapped(client,
> -                                                  MAX31790_REG_PWMOUT(channel),
> -                                                  data->pwm[channel]);
> +               err = write_reg_word(regmap, MAX31790_REG_PWMOUT(channel), val << 8);
>                 break;
>         case hwmon_pwm_enable:
>                 fan_config = data->fan_config[channel];
> @@ -321,9 +328,9 @@ static int max31790_write_pwm(struct device *dev, u32 attr, int channel,
>                         break;
>                 }
>                 data->fan_config[channel] = fan_config;
> -               err = i2c_smbus_write_byte_data(client,
> -                                       MAX31790_REG_FAN_CONFIG(channel),
> -                                       fan_config);
> +               err = regmap_write(regmap,
> +                                  MAX31790_REG_FAN_CONFIG(channel),
> +                                  fan_config);
>                 break;
>         default:
>                 err = -EOPNOTSUPP;
> @@ -426,20 +433,18 @@ static const struct hwmon_chip_info max31790_chip_info = {
>         .info = max31790_info,
>  };
>
> -static int max31790_init_client(struct i2c_client *client,
> +static int max31790_init_client(struct regmap *regmap,
>                                 struct max31790_data *data)
>  {
>         int i, rv;
>
>         for (i = 0; i < NR_CHANNEL; i++) {
> -               rv = i2c_smbus_read_byte_data(client,
> -                               MAX31790_REG_FAN_CONFIG(i));
> +               rv = read_reg_byte(regmap, MAX31790_REG_FAN_CONFIG(i % NR_CHANNEL));
>                 if (rv < 0)
>                         return rv;
>                 data->fan_config[i] = rv;
>
> -               rv = i2c_smbus_read_byte_data(client,
> -                               MAX31790_REG_FAN_DYNAMICS(i));
> +               rv = read_reg_byte(regmap, MAX31790_REG_FAN_DYNAMICS(i));
>                 if (rv < 0)
>                         return rv;
>                 data->fan_dynamics[i] = rv;
> @@ -464,13 +469,18 @@ static int max31790_probe(struct i2c_client *client)
>         if (!data)
>                 return -ENOMEM;
>
> -       data->client = client;
>         mutex_init(&data->update_lock);
>
> +       data->regmap = devm_regmap_init_i2c(client, &max31790_regmap_config);
> +       if (IS_ERR(data->regmap)) {
> +               dev_err(dev, "failed to allocate register map\n");
> +               return PTR_ERR(data->regmap);
> +       }
> +
>         /*
>          * Initialize the max31790 chip
>          */
> -       err = max31790_init_client(client, data);
> +       err = max31790_init_client(data->regmap, data);
>         if (err)
>                 return err;
>
> --
> 2.31.1
>