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Date: Wed, 19 May 2021 12:00:22 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Václav Kubernát <kubernat@...net.cz>,
Jean Delvare <jdelvare@...e.com>,
Jonathan Corbet <corbet@....net>, linux-hwmon@...r.kernel.org,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 1/5] hwmon: (max31790) Rework to use regmap
On 5/11/21 6:30 PM, Václav Kubernát wrote:
> 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@...net.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 54f04e61fb83..c2ec57672c4e 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1092,6 +1092,7 @@ 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,
This should be:
.range_max = MAX31790_REG_PWM_DUTY_CYCLE(5) + 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),
This should be:
regmap_reg_range(MAX31790_REG_PWM_DUTY_CYCLE(0), MAX31790_REG_PWM_DUTY_CYCLE(5) + 1),
regmap_reg_range(MAX31790_REG_TACH_COUNT(0), MAX31790_REG_TACH_COUNT(11) + 1),
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
.yes_ranges = max31790_volatile_ranges,
.n_yes_ranges = ARRAY_SIZE(max31790_volatile_ranges),
Initializing with 0 is not necessary for static variables.
> +};
> +
As I have already said and now confirmed, specifying volatile ranges as no_ranges
is wrong. This only "works" because the cache method is specified implicitly as
REGCACHE_NONE, ie it has no effect.
> +static const struct regmap_config max31790_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .reg_stride = 1,
> + .max_register = MAX31790_REG_USER_BYTE_67,
Add:
.num_reg_defaults_raw = MAX31790_REG_USER_BYTE_67 + 1,
.cache_type = REGCACHE_FLAT,
for caching to really work.
> + .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;
>
>
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