| Message ID | 20231026144405.546822-4-daniel.matyas@analog.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v5,1/4] hwmon: max31827: Handle new properties from the devicetree | expand |
On 10/26/23 07:44, Daniel Matyas wrote: > Added custom channel-specific (temp1) attribute for resolution. The wait > time for a conversion in one-shot mode (enable = 0) depends on the > resolution. > > When resolution is 12-bit, the conversion time is 140ms, but the minimum > update_interval is 125ms. Handled this problem by waiting an additional > 15ms (125ms + 15ms = 140ms). > > Added 'mask' parameter to the shutdown_write() function. Now it can > either write or update bits, depending on the value of mask. This is > needed, because for alarms a write is necessary, but for resolution only > the resolution bits should be updated. > > Signed-off-by: Daniel Matyas <daniel.matyas@analog.com> > --- > > v4 -> v5: No change. > > v3 -> v4: No change. > > v2 -> v3: Fixed indentation problems in .rst. > > v1 -> v2: Changed subject. Separated patch. Removed timeout sysfs > attribute and kept only resolution. Added temp1_ prefix to resolution. > Changed value of resolution from bits to milli-degrees Celsius. Added > appropriate documentation. > > > Documentation/hwmon/max31827.rst | 29 ++++++-- > drivers/hwmon/max31827.c | 121 ++++++++++++++++++++++++++++--- > 2 files changed, 134 insertions(+), 16 deletions(-) > > diff --git a/Documentation/hwmon/max31827.rst b/Documentation/hwmon/max31827.rst > index a8bbfb85dd02..44ab9dc064cb 100644 > --- a/Documentation/hwmon/max31827.rst > +++ b/Documentation/hwmon/max31827.rst > @@ -90,11 +90,28 @@ the data sheet are: > > Enabling the device when it is already enabled has the side effect of setting > the conversion frequency to 1 conv/s. The conversion time varies depending on > -the resolution. The conversion time doubles with every bit of increased > -resolution. For 10 bit resolution 35ms are needed, while for 12 bit resolution > -(default) 140ms. When chip is in shutdown mode and a read operation is > -requested, one-shot is triggered, the device waits for 140 (conversion time) ms, > -and only after that is the temperature value register read. > +the resolution. > + > +The conversion time doubles with every bit of increased resolution. The > +available resolutions are: > + > +- 8 bit -> 8.75 ms conversion time > +- 9 bit -> 17.5 ms conversion time > +- 10 bit -> 35 ms conversion time > +- 12 bit (default) -> 140 ms conversion time > + > +There is a temp1_resolution attribute which indicates the unit change in the > +input temperature in milli-degrees C. > + > +- 1000 mC -> 8 bit > +- 500 mC -> 9 bit > +- 250 mC -> 10 bit > +- 62 mC -> 12 bit (default) - actually this is 62.5, but the fil returns 62 fil ? Should that be "attribute" ? > + > +When chip is in shutdown mode and a read operation is requested, one-shot is > +triggered, the device waits for <conversion time> ms, and only after that is > +the temperature value register read. Note that the conversion times are rounded > +up to the nearest possible integer. > > The LSB of the temperature values is 0.0625 degrees Celsius, but the values of > the temperatures are displayed in milli-degrees. This means, that some data is > @@ -117,4 +134,4 @@ corresponding status bits. > Notes > ----- > > -PEC and resolution are not implemented. > +PEC is not implemented. > diff --git a/drivers/hwmon/max31827.c b/drivers/hwmon/max31827.c > index 8ba387b51157..c9fa6d4d6194 100644 > --- a/drivers/hwmon/max31827.c > +++ b/drivers/hwmon/max31827.c > @@ -37,6 +37,9 @@ > #define MAX31827_CONFIGURATION_U_TEMP_STAT_MASK BIT(14) > #define MAX31827_CONFIGURATION_O_TEMP_STAT_MASK BIT(15) > > +#define MAX31827_8_BIT_CNV_TIME 9 > +#define MAX31827_9_BIT_CNV_TIME 18 > +#define MAX31827_10_BIT_CNV_TIME 35 > #define MAX31827_12_BIT_CNV_TIME 140 > > #define MAX31827_ALRM_POL_HIGH 0x1 > @@ -68,6 +71,27 @@ static const u16 max31827_conversions[] = { > [MAX31827_CNV_8_HZ] = 125, > }; > > +enum max31827_resolution { > + MAX31827_RES_8_BIT = 0, > + MAX31827_RES_9_BIT, > + MAX31827_RES_10_BIT, > + MAX31827_RES_12_BIT, > +}; > + > +static const u16 max31827_resolutions[] = { > + [MAX31827_RES_8_BIT] = 1000, > + [MAX31827_RES_9_BIT] = 500, > + [MAX31827_RES_10_BIT] = 250, > + [MAX31827_RES_12_BIT] = 62, > +}; > + > +static const u16 max31827_conv_times[] = { > + [MAX31827_RES_8_BIT] = MAX31827_8_BIT_CNV_TIME, > + [MAX31827_RES_9_BIT] = MAX31827_9_BIT_CNV_TIME, > + [MAX31827_RES_10_BIT] = MAX31827_10_BIT_CNV_TIME, > + [MAX31827_RES_12_BIT] = MAX31827_12_BIT_CNV_TIME, > +}; > + > struct max31827_state { > /* > * Prevent simultaneous access to the i2c client. > @@ -75,6 +99,8 @@ struct max31827_state { > struct mutex lock; > struct regmap *regmap; > bool enable; > + unsigned int resolution; > + unsigned int update_interval; > }; > > static const struct regmap_config max31827_regmap = { > @@ -91,9 +117,9 @@ static int shutdown_write(struct max31827_state *st, unsigned int reg, > int ret; > > /* > - * Before the Temperature Threshold Alarm and Alarm Hysteresis Threshold > - * register values are changed over I2C, the part must be in shutdown > - * mode. > + * Before the Temperature Threshold Alarm, Alarm Hysteresis Threshold > + * and Resolution bits from Configuration register are changed over I2C, > + * the part must be in shutdown mode. > * > * Mutex is used to ensure, that some other process doesn't change the > * configuration register. > @@ -211,9 +237,18 @@ static int max31827_read(struct device *dev, enum hwmon_sensor_types type, > mutex_unlock(&st->lock); > return ret; > } > - > - msleep(MAX31827_12_BIT_CNV_TIME); > + msleep(max31827_conv_times[st->resolution]); > } > + > + /* > + * For 12-bit resolution the conversion time is 140 ms, > + * thus an additional 15 ms is needed to complete the > + * conversion: 125 ms + 15 ms = 140 ms > + */ > + if (max31827_resolutions[st->resolution] == 12 && > + st->update_interval == 125) > + usleep_range(15000, 20000); > + > ret = regmap_read(st->regmap, MAX31827_T_REG, &uval); > > mutex_unlock(&st->lock); > @@ -371,10 +406,14 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type, > res = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK, > res); > > - return regmap_update_bits(st->regmap, > - MAX31827_CONFIGURATION_REG, > - MAX31827_CONFIGURATION_CNV_RATE_MASK, > - res); > + ret = regmap_update_bits(st->regmap, > + MAX31827_CONFIGURATION_REG, > + MAX31827_CONFIGURATION_CNV_RATE_MASK, > + res); > + if (ret) > + return ret; > + > + st->update_interval = val; > } > break; > > @@ -385,6 +424,68 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type, > return -EOPNOTSUPP; > } > > +static ssize_t temp1_resolution_show(struct device *dev, > + struct device_attribute *devattr, > + char *buf) > +{ > + struct max31827_state *st = dev_get_drvdata(dev); > + unsigned int val; > + int ret; > + > + ret = regmap_read(st->regmap, MAX31827_CONFIGURATION_REG, &val); > + if (ret) > + return ret; > + > + val = FIELD_GET(MAX31827_CONFIGURATION_RESOLUTION_MASK, val); > + > + return scnprintf(buf, PAGE_SIZE, "%u\n", max31827_resolutions[val]); > +} > + > +static ssize_t temp1_resolution_store(struct device *dev, > + struct device_attribute *devattr, > + const char *buf, size_t count) > +{ > + struct max31827_state *st = dev_get_drvdata(dev); > + unsigned int idx = 0; > + unsigned int val; > + int ret; > + > + ret = kstrtouint(buf, 10, &val); > + if (ret) > + return ret; > + > + /* > + * Convert the desired resolution into register > + * bits. idx is already initialized with 0. > + * > + * This was inspired by lm73 driver. > + */ > + while (idx < ARRAY_SIZE(max31827_resolutions) && > + val < max31827_resolutions[idx]) > + idx++; > + > + if (idx == ARRAY_SIZE(max31827_resolutions) || > + val != max31827_resolutions[idx]) > + return -EOPNOTSUPP; -EINVAL Question here is if this should return the closest value/index or return an error. Traditionally, for ranges like this, drivers would accept all values and select the closest supported value. [ just as the lm73 driver, which is listed as example here, does ] There are even helper functions for that - find_closest() or find_closest_descending(). I would very much prefer the more flexible approach and not burden the user with having to find supported values. > + > + st->resolution = idx; > + > + ret = shutdown_write(st, MAX31827_CONFIGURATION_REG, > + MAX31827_CONFIGURATION_RESOLUTION_MASK, > + FIELD_PREP(MAX31827_CONFIGURATION_RESOLUTION_MASK, > + idx)); > + > + return (ret) ? ret : count; drop () around ret > +} > + > +static DEVICE_ATTR_RW(temp1_resolution); > + > +static struct attribute *max31827_attrs[] = { > + &dev_attr_temp1_resolution.attr, > + NULL > +}; > +ATTRIBUTE_GROUPS(max31827); > + > static const struct i2c_device_id max31827_i2c_ids[] = { > { "max31827", max31827 }, > { "max31828", max31828 }, > @@ -501,7 +602,7 @@ static int max31827_probe(struct i2c_client *client) > > hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, st, > &max31827_chip_info, > - NULL); > + max31827_groups); > > return PTR_ERR_OR_ZERO(hwmon_dev); > }
diff --git a/Documentation/hwmon/max31827.rst b/Documentation/hwmon/max31827.rst index a8bbfb85dd02..44ab9dc064cb 100644 --- a/Documentation/hwmon/max31827.rst +++ b/Documentation/hwmon/max31827.rst @@ -90,11 +90,28 @@ the data sheet are: Enabling the device when it is already enabled has the side effect of setting the conversion frequency to 1 conv/s. The conversion time varies depending on -the resolution. The conversion time doubles with every bit of increased -resolution. For 10 bit resolution 35ms are needed, while for 12 bit resolution -(default) 140ms. When chip is in shutdown mode and a read operation is -requested, one-shot is triggered, the device waits for 140 (conversion time) ms, -and only after that is the temperature value register read. +the resolution. + +The conversion time doubles with every bit of increased resolution. The +available resolutions are: + +- 8 bit -> 8.75 ms conversion time +- 9 bit -> 17.5 ms conversion time +- 10 bit -> 35 ms conversion time +- 12 bit (default) -> 140 ms conversion time + +There is a temp1_resolution attribute which indicates the unit change in the +input temperature in milli-degrees C. + +- 1000 mC -> 8 bit +- 500 mC -> 9 bit +- 250 mC -> 10 bit +- 62 mC -> 12 bit (default) - actually this is 62.5, but the fil returns 62 + +When chip is in shutdown mode and a read operation is requested, one-shot is +triggered, the device waits for <conversion time> ms, and only after that is +the temperature value register read. Note that the conversion times are rounded +up to the nearest possible integer. The LSB of the temperature values is 0.0625 degrees Celsius, but the values of the temperatures are displayed in milli-degrees. This means, that some data is @@ -117,4 +134,4 @@ corresponding status bits. Notes ----- -PEC and resolution are not implemented. +PEC is not implemented. diff --git a/drivers/hwmon/max31827.c b/drivers/hwmon/max31827.c index 8ba387b51157..c9fa6d4d6194 100644 --- a/drivers/hwmon/max31827.c +++ b/drivers/hwmon/max31827.c @@ -37,6 +37,9 @@ #define MAX31827_CONFIGURATION_U_TEMP_STAT_MASK BIT(14) #define MAX31827_CONFIGURATION_O_TEMP_STAT_MASK BIT(15) +#define MAX31827_8_BIT_CNV_TIME 9 +#define MAX31827_9_BIT_CNV_TIME 18 +#define MAX31827_10_BIT_CNV_TIME 35 #define MAX31827_12_BIT_CNV_TIME 140 #define MAX31827_ALRM_POL_HIGH 0x1 @@ -68,6 +71,27 @@ static const u16 max31827_conversions[] = { [MAX31827_CNV_8_HZ] = 125, }; +enum max31827_resolution { + MAX31827_RES_8_BIT = 0, + MAX31827_RES_9_BIT, + MAX31827_RES_10_BIT, + MAX31827_RES_12_BIT, +}; + +static const u16 max31827_resolutions[] = { + [MAX31827_RES_8_BIT] = 1000, + [MAX31827_RES_9_BIT] = 500, + [MAX31827_RES_10_BIT] = 250, + [MAX31827_RES_12_BIT] = 62, +}; + +static const u16 max31827_conv_times[] = { + [MAX31827_RES_8_BIT] = MAX31827_8_BIT_CNV_TIME, + [MAX31827_RES_9_BIT] = MAX31827_9_BIT_CNV_TIME, + [MAX31827_RES_10_BIT] = MAX31827_10_BIT_CNV_TIME, + [MAX31827_RES_12_BIT] = MAX31827_12_BIT_CNV_TIME, +}; + struct max31827_state { /* * Prevent simultaneous access to the i2c client. @@ -75,6 +99,8 @@ struct max31827_state { struct mutex lock; struct regmap *regmap; bool enable; + unsigned int resolution; + unsigned int update_interval; }; static const struct regmap_config max31827_regmap = { @@ -91,9 +117,9 @@ static int shutdown_write(struct max31827_state *st, unsigned int reg, int ret; /* - * Before the Temperature Threshold Alarm and Alarm Hysteresis Threshold - * register values are changed over I2C, the part must be in shutdown - * mode. + * Before the Temperature Threshold Alarm, Alarm Hysteresis Threshold + * and Resolution bits from Configuration register are changed over I2C, + * the part must be in shutdown mode. * * Mutex is used to ensure, that some other process doesn't change the * configuration register. @@ -211,9 +237,18 @@ static int max31827_read(struct device *dev, enum hwmon_sensor_types type, mutex_unlock(&st->lock); return ret; } - - msleep(MAX31827_12_BIT_CNV_TIME); + msleep(max31827_conv_times[st->resolution]); } + + /* + * For 12-bit resolution the conversion time is 140 ms, + * thus an additional 15 ms is needed to complete the + * conversion: 125 ms + 15 ms = 140 ms + */ + if (max31827_resolutions[st->resolution] == 12 && + st->update_interval == 125) + usleep_range(15000, 20000); + ret = regmap_read(st->regmap, MAX31827_T_REG, &uval); mutex_unlock(&st->lock); @@ -371,10 +406,14 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type, res = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK, res); - return regmap_update_bits(st->regmap, - MAX31827_CONFIGURATION_REG, - MAX31827_CONFIGURATION_CNV_RATE_MASK, - res); + ret = regmap_update_bits(st->regmap, + MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_CNV_RATE_MASK, + res); + if (ret) + return ret; + + st->update_interval = val; } break; @@ -385,6 +424,68 @@ static int max31827_write(struct device *dev, enum hwmon_sensor_types type, return -EOPNOTSUPP; } +static ssize_t temp1_resolution_show(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct max31827_state *st = dev_get_drvdata(dev); + unsigned int val; + int ret; + + ret = regmap_read(st->regmap, MAX31827_CONFIGURATION_REG, &val); + if (ret) + return ret; + + val = FIELD_GET(MAX31827_CONFIGURATION_RESOLUTION_MASK, val); + + return scnprintf(buf, PAGE_SIZE, "%u\n", max31827_resolutions[val]); +} + +static ssize_t temp1_resolution_store(struct device *dev, + struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct max31827_state *st = dev_get_drvdata(dev); + unsigned int idx = 0; + unsigned int val; + int ret; + + ret = kstrtouint(buf, 10, &val); + if (ret) + return ret; + + /* + * Convert the desired resolution into register + * bits. idx is already initialized with 0. + * + * This was inspired by lm73 driver. + */ + while (idx < ARRAY_SIZE(max31827_resolutions) && + val < max31827_resolutions[idx]) + idx++; + + if (idx == ARRAY_SIZE(max31827_resolutions) || + val != max31827_resolutions[idx]) + return -EOPNOTSUPP; + + st->resolution = idx; + + ret = shutdown_write(st, MAX31827_CONFIGURATION_REG, + MAX31827_CONFIGURATION_RESOLUTION_MASK, + FIELD_PREP(MAX31827_CONFIGURATION_RESOLUTION_MASK, + idx)); + + return (ret) ? ret : count; +} + +static DEVICE_ATTR_RW(temp1_resolution); + +static struct attribute *max31827_attrs[] = { + &dev_attr_temp1_resolution.attr, + NULL +}; +ATTRIBUTE_GROUPS(max31827); + static const struct i2c_device_id max31827_i2c_ids[] = { { "max31827", max31827 }, { "max31828", max31828 }, @@ -501,7 +602,7 @@ static int max31827_probe(struct i2c_client *client) hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, st, &max31827_chip_info, - NULL); + max31827_groups); return PTR_ERR_OR_ZERO(hwmon_dev); }
Added custom channel-specific (temp1) attribute for resolution. The wait time for a conversion in one-shot mode (enable = 0) depends on the resolution. When resolution is 12-bit, the conversion time is 140ms, but the minimum update_interval is 125ms. Handled this problem by waiting an additional 15ms (125ms + 15ms = 140ms). Added 'mask' parameter to the shutdown_write() function. Now it can either write or update bits, depending on the value of mask. This is needed, because for alarms a write is necessary, but for resolution only the resolution bits should be updated. Signed-off-by: Daniel Matyas <daniel.matyas@analog.com> --- v4 -> v5: No change. v3 -> v4: No change. v2 -> v3: Fixed indentation problems in .rst. v1 -> v2: Changed subject. Separated patch. Removed timeout sysfs attribute and kept only resolution. Added temp1_ prefix to resolution. Changed value of resolution from bits to milli-degrees Celsius. Added appropriate documentation. Documentation/hwmon/max31827.rst | 29 ++++++-- drivers/hwmon/max31827.c | 121 ++++++++++++++++++++++++++++--- 2 files changed, 134 insertions(+), 16 deletions(-)