* Add a documentation file for the device. * Respect a bit more the kernel-doc syntax. * Rename some variables for clarity. * Move the creation of sysfs attributes after the end of the initialization in the probe function, and remove them in the error path. * Release regulator in the error path. Signed-off-by: Vivien Didelot <vivien.didelot@xxxxxxxxxxxxxxxxxxxx> --- Documentation/hwmon/sht15 | 43 ++++++++ drivers/hwmon/sht15.c | 264 +++++++++++++++++++++++++++------------------ include/linux/sht15.h | 12 ++- 3 files changed, 208 insertions(+), 111 deletions(-) create mode 100644 Documentation/hwmon/sht15 diff --git a/Documentation/hwmon/sht15 b/Documentation/hwmon/sht15 new file mode 100644 index 0000000..50c07f5 --- /dev/null +++ b/Documentation/hwmon/sht15 @@ -0,0 +1,43 @@ +Kernel driver sht15 +=================== + +Authors: + * Wouter Horre + * Jonathan Cameron + +Supported chips: + * Sensirion SHT10 + Prefix: 'sht10' + + * Sensirion SHT11 + Prefix: 'sht11' + + * Sensirion SHT15 + Prefix: 'sht15' + + * Sensirion SHT71 + Prefix: 'sht71' + + * Sensirion SHT75 + Prefix: 'sht75' + +Datasheet: Publicly available at the Sensirion website +http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf + +Description +----------- + +The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature +sensors. + +The devices communicate using two GPIO lines and use the default +resolution settings of 14 bits for temperature and 12 bits for humidity. + +Note: The regulator supply name is set to "vcc". + +Sysfs interface +--------------- + +* temp1_input: temperature input +* humidity1_input: humidity input + diff --git a/drivers/hwmon/sht15.c b/drivers/hwmon/sht15.c index 1a9c32d..711c06a 100644 --- a/drivers/hwmon/sht15.c +++ b/drivers/hwmon/sht15.c @@ -9,16 +9,7 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * - * Currently ignoring checksum on readings. - * Default resolution only (14bit temp, 12bit humidity) - * Ignoring battery status. - * Heater not enabled. - * Timings are all conservative. - * - * Data sheet available (1/2009) at - * http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf - * - * Regulator supply name = vcc + * For further information, see the Documentation/hwmon/sht15 file. */ #include <linux/interrupt.h> @@ -39,17 +30,17 @@ #include <linux/slab.h> #include <asm/atomic.h> -#define SHT15_MEASURE_TEMP 3 -#define SHT15_MEASURE_RH 5 +#define SHT15_MEASURE_TEMP 3 +#define SHT15_MEASURE_RH 5 -#define SHT15_READING_NOTHING 0 -#define SHT15_READING_TEMP 1 -#define SHT15_READING_HUMID 2 +#define SHT15_READING_NOTHING 0 +#define SHT15_READING_TEMP 1 +#define SHT15_READING_HUMID 2 /* Min timings in nsecs */ -#define SHT15_TSCKL 100 /* clock low */ -#define SHT15_TSCKH 100 /* clock high */ -#define SHT15_TSU 150 /* data setup time */ +#define SHT15_TSCKL 100 /* clock low */ +#define SHT15_TSCKH 100 /* clock high */ +#define SHT15_TSU 150 /* data setup time */ /** * struct sht15_temppair - elements of voltage dependant temp calc @@ -61,9 +52,7 @@ struct sht15_temppair { int d1; }; -/* Table 9 from data sheet - relates temperature calculation - * to supply voltage. - */ +/* Table 9 from datasheet - relates temperature calculation to supply voltage */ static const struct sht15_temppair temppoints[] = { { 2500000, -39400 }, { 3000000, -39600 }, @@ -74,27 +63,27 @@ static const struct sht15_temppair temppoints[] = { /** * struct sht15_data - device instance specific data - * @pdata: platform data (gpio's etc) - * @read_work: bh of interrupt handler - * @wait_queue: wait queue for getting values from device - * @val_temp: last temperature value read from device - * @val_humid: last humidity value read from device - * @flag: status flag used to identify what the last request was - * @valid: are the current stored values valid (start condition) - * @last_updat: time of last update - * @read_lock: mutex to ensure only one read in progress - * at a time. - * @dev: associate device structure - * @hwmon_dev: device associated with hwmon subsystem - * @reg: associated regulator (if specified) - * @nb: notifier block to handle notifications of voltage changes - * @supply_uV: local copy of supply voltage used to allow - * use of regulator consumer if available - * @supply_uV_valid: indicates that an updated value has not yet - * been obtained from the regulator and so any calculations - * based upon it will be invalid. - * @update_supply_work: work struct that is used to update the supply_uV - * @interrupt_handled: flag used to indicate a hander has been scheduled + * @pdata: platform data (gpio's etc). + * @read_work: bh of interrupt handler. + * @wait_queue: wait queue for getting values from device. + * @val_temp: last temperature value read from device. + * @val_humid: last humidity value read from device. + * @flag: status flag used to identify what the last request was. + * @measures_valid: are the current stored measures valid (start condition). + * @last_measure: time of last measure. + * @read_lock: mutex to ensure only one read in progress at a time. + * @dev: associate device structure. + * @hwmon_dev: device associated with hwmon subsystem. + * @reg: associated regulator (if specified). + * @nb: notifier block to handle notifications of voltage + * changes. + * @supply_uV: local copy of supply voltage used to allow use of + * regulator consumer if available. + * @supply_uV_valid: indicates that an updated value has not yet been + * obtained from the regulator and so any calculations + * based upon it will be invalid. + * @update_supply_work: work struct that is used to update the supply_uV. + * @interrupt_handled: flag used to indicate a handler has been scheduled. */ struct sht15_data { struct sht15_platform_data *pdata; @@ -103,8 +92,8 @@ struct sht15_data { uint16_t val_temp; uint16_t val_humid; u8 flag; - u8 valid; - unsigned long last_updat; + u8 measures_valid; + unsigned long last_measure; struct mutex read_lock; struct device *dev; struct device *hwmon_dev; @@ -125,6 +114,7 @@ struct sht15_data { static void sht15_connection_reset(struct sht15_data *data) { int i; + gpio_direction_output(data->pdata->gpio_data, 1); ndelay(SHT15_TSCKL); gpio_set_value(data->pdata->gpio_sck, 0); @@ -136,14 +126,14 @@ static void sht15_connection_reset(struct sht15_data *data) ndelay(SHT15_TSCKL); } } + /** * sht15_send_bit() - send an individual bit to the device * @data: device state data * @val: value of bit to be sent - **/ + */ static inline void sht15_send_bit(struct sht15_data *data, int val) { - gpio_set_value(data->pdata->gpio_data, val); ndelay(SHT15_TSU); gpio_set_value(data->pdata->gpio_sck, 1); @@ -154,12 +144,12 @@ static inline void sht15_send_bit(struct sht15_data *data, int val) /** * sht15_transmission_start() - specific sequence for new transmission - * * @data: device state data + * * Timings for this are not documented on the data sheet, so very * conservative ones used in implementation. This implements * figure 12 on the data sheet. - **/ + */ static void sht15_transmission_start(struct sht15_data *data) { /* ensure data is high and output */ @@ -180,23 +170,26 @@ static void sht15_transmission_start(struct sht15_data *data) gpio_set_value(data->pdata->gpio_sck, 0); ndelay(SHT15_TSCKL); } + /** * sht15_send_byte() - send a single byte to the device * @data: device state * @byte: value to be sent - **/ + */ static void sht15_send_byte(struct sht15_data *data, u8 byte) { int i; + for (i = 0; i < 8; i++) { sht15_send_bit(data, !!(byte & 0x80)); byte <<= 1; } } + /** * sht15_wait_for_response() - checks for ack from device * @data: device state - **/ + */ static int sht15_wait_for_response(struct sht15_data *data) { gpio_direction_input(data->pdata->gpio_data); @@ -220,27 +213,30 @@ static int sht15_wait_for_response(struct sht15_data *data) * * On entry, sck is output low, data is output pull high * and the interrupt disabled. - **/ + */ static int sht15_send_cmd(struct sht15_data *data, u8 cmd) { int ret = 0; + sht15_transmission_start(data); sht15_send_byte(data, cmd); ret = sht15_wait_for_response(data); return ret; } + /** - * sht15_update_single_val() - get a new value from device + * sht15_measure() - get a new value from device * @data: device instance specific data * @command: command sent to request value * @timeout_msecs: timeout after which comms are assumed * to have failed are reset. - **/ -static inline int sht15_update_single_val(struct sht15_data *data, - int command, - int timeout_msecs) + */ +static int sht15_measure(struct sht15_data *data, + int command, + int timeout_msecs) { int ret; + ret = sht15_send_cmd(data, command); if (ret) return ret; @@ -267,27 +263,27 @@ static inline int sht15_update_single_val(struct sht15_data *data, } /** - * sht15_update_vals() - get updated readings from device if too old + * sht15_update_measures() - get updated measures from device if too old * @data: device state - **/ -static int sht15_update_vals(struct sht15_data *data) + */ +static int sht15_update_measures(struct sht15_data *data) { int ret = 0; int timeout = HZ; mutex_lock(&data->read_lock); - if (time_after(jiffies, data->last_updat + timeout) - || !data->valid) { + if (time_after(jiffies, data->last_measure + timeout) + || !data->measures_valid) { data->flag = SHT15_READING_HUMID; - ret = sht15_update_single_val(data, SHT15_MEASURE_RH, 160); + ret = sht15_measure(data, SHT15_MEASURE_RH, 160); if (ret) goto error_ret; data->flag = SHT15_READING_TEMP; - ret = sht15_update_single_val(data, SHT15_MEASURE_TEMP, 400); + ret = sht15_measure(data, SHT15_MEASURE_TEMP, 400); if (ret) goto error_ret; - data->valid = 1; - data->last_updat = jiffies; + data->measures_valid = 1; + data->last_measure = jiffies; } error_ret: mutex_unlock(&data->read_lock); @@ -300,7 +296,7 @@ error_ret: * @data: device state * * As per section 4.3 of the data sheet. - **/ + */ static inline int sht15_calc_temp(struct sht15_data *data) { int d1 = temppoints[0].d1; @@ -316,7 +312,7 @@ static inline int sht15_calc_temp(struct sht15_data *data) break; } - return data->val_temp*10 + d1; + return data->val_temp * 10 + d1; } /** @@ -325,23 +321,35 @@ static inline int sht15_calc_temp(struct sht15_data *data) * * This is the temperature compensated version as per section 4.2 of * the data sheet. - **/ + * + * The sensor is assumed to be V3, which is compatible with V4. + * Humidity conversion coefficients are shown in table 7 of the datasheet. + */ static inline int sht15_calc_humid(struct sht15_data *data) { - int RHlinear; /* milli percent */ + int rh_linear; /* milli percent */ int temp = sht15_calc_temp(data); const int c1 = -4; const int c2 = 40500; /* x 10 ^ -6 */ - const int c3 = -28; /* x 10 ^ -7 */ + const int c3 = -28; /* x 10 ^ -7 */ - RHlinear = c1*1000 - + c2 * data->val_humid/1000 + rh_linear = c1 * 1000 + + c2 * data->val_humid / 1000 + (data->val_humid * data->val_humid * c3) / 10000; return (temp - 25000) * (10000 + 80 * data->val_humid) - / 1000000 + RHlinear; + / 1000000 + rh_linear; } +/** + * sht15_show_temp() - show temperature measurement value in sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer where measurement values are written to. + * + * Will be called on read access to temp1_input sysfs attribute. + * Returns number of bytes written into buffer, negative errno on error. + */ static ssize_t sht15_show_temp(struct device *dev, struct device_attribute *attr, char *buf) @@ -350,12 +358,21 @@ static ssize_t sht15_show_temp(struct device *dev, struct sht15_data *data = dev_get_drvdata(dev); /* Technically no need to read humidity as well */ - ret = sht15_update_vals(data); + ret = sht15_update_measures(data); return ret ? ret : sprintf(buf, "%d\n", sht15_calc_temp(data)); } +/** + * sht15_show_humidity() - show humidity measurement value in sysfs + * @dev: device. + * @attr: device attribute. + * @buf: sysfs buffer where measurement values are written to. + * + * Will be called on read access to humidity1_input sysfs attribute. + * Returns number of bytes written into buffer, negative errno on error. + */ static ssize_t sht15_show_humidity(struct device *dev, struct device_attribute *attr, char *buf) @@ -363,11 +380,12 @@ static ssize_t sht15_show_humidity(struct device *dev, int ret; struct sht15_data *data = dev_get_drvdata(dev); - ret = sht15_update_vals(data); + ret = sht15_update_measures(data); return ret ? ret : sprintf(buf, "%d\n", sht15_calc_humid(data)); -}; +} + static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf) @@ -397,6 +415,7 @@ static const struct attribute_group sht15_attr_group = { static irqreturn_t sht15_interrupt_fired(int irq, void *d) { struct sht15_data *data = d; + /* First disable the interrupt */ disable_irq_nosync(irq); atomic_inc(&data->interrupt_handled); @@ -406,7 +425,10 @@ static irqreturn_t sht15_interrupt_fired(int irq, void *d) return IRQ_HANDLED; } -/* Each byte of data is acknowledged by pulling the data line +/** + * sht15_ack() - Send an ack to the device + * + * Each byte of data is acknowledged by pulling the data line * low for one clock pulse. */ static void sht15_ack(struct sht15_data *data) @@ -421,12 +443,13 @@ static void sht15_ack(struct sht15_data *data) gpio_direction_input(data->pdata->gpio_data); } + /** * sht15_end_transmission() - notify device of end of transmission * @data: device state * * This is basically a NAK. (single clock pulse, data high) - **/ + */ static void sht15_end_transmission(struct sht15_data *data) { gpio_direction_output(data->pdata->gpio_data, 1); @@ -444,12 +467,13 @@ static void sht15_bh_read_data(struct work_struct *work_s) struct sht15_data *data = container_of(work_s, struct sht15_data, read_work); + /* Firstly, verify the line is low */ if (gpio_get_value(data->pdata->gpio_data)) { - /* If not, then start the interrupt again - care - here as could have gone low in meantime so verify - it hasn't! - */ + /* + * If not, then start the interrupt again - care here as could + * have gone low in meantime so verify it hasn't! + */ atomic_set(&data->interrupt_handled, 0); enable_irq(gpio_to_irq(data->pdata->gpio_data)); /* If still not occured or another handler has been scheduled */ @@ -457,6 +481,7 @@ static void sht15_bh_read_data(struct work_struct *work_s) || atomic_read(&data->interrupt_handled)) return; } + /* Read the data back from the device */ for (i = 0; i < 16; ++i) { val <<= 1; @@ -468,6 +493,7 @@ static void sht15_bh_read_data(struct work_struct *work_s) if (i == 7) sht15_ack(data); } + /* Tell the device we are done */ sht15_end_transmission(data); @@ -500,10 +526,10 @@ static void sht15_update_voltage(struct work_struct *work_s) * * Note that as the notification code holds the regulator lock, we have * to schedule an update of the supply voltage rather than getting it directly. - **/ + */ static int sht15_invalidate_voltage(struct notifier_block *nb, - unsigned long event, - void *ignored) + unsigned long event, + void *ignored) { struct sht15_data *data = container_of(nb, struct sht15_data, nb); @@ -521,7 +547,7 @@ static int __devinit sht15_probe(struct platform_device *pdev) if (!data) { ret = -ENOMEM; - dev_err(&pdev->dev, "kzalloc failed"); + dev_err(&pdev->dev, "kzalloc failed\n"); goto error_ret; } @@ -533,13 +559,16 @@ static int __devinit sht15_probe(struct platform_device *pdev) init_waitqueue_head(&data->wait_queue); if (pdev->dev.platform_data == NULL) { - dev_err(&pdev->dev, "no platform data supplied"); + dev_err(&pdev->dev, "no platform data supplied\n"); goto err_free_data; } data->pdata = pdev->dev.platform_data; - data->supply_uV = data->pdata->supply_mv*1000; + data->supply_uV = data->pdata->supply_mv * 1000; -/* If a regulator is available, query what the supply voltage actually is!*/ + /* + * If a regulator is available, + * query what the supply voltage actually is! + */ data->reg = regulator_get(data->dev, "vcc"); if (!IS_ERR(data->reg)) { int voltage; @@ -549,28 +578,34 @@ static int __devinit sht15_probe(struct platform_device *pdev) data->supply_uV = voltage; regulator_enable(data->reg); - /* setup a notifier block to update this if another device - * causes the voltage to change */ + /* + * Setup a notifier block to update this if another device + * causes the voltage to change + */ data->nb.notifier_call = &sht15_invalidate_voltage; ret = regulator_register_notifier(data->reg, &data->nb); + if (ret) { + dev_err(&pdev->dev, + "regulator notifier request failed\n"); + regulator_disable(data->reg); + regulator_put(data->reg); + goto err_free_data; + } } -/* Try requesting the GPIOs */ + + /* Try requesting the GPIOs */ ret = gpio_request(data->pdata->gpio_sck, "SHT15 sck"); if (ret) { - dev_err(&pdev->dev, "gpio request failed"); - goto err_free_data; + dev_err(&pdev->dev, "gpio request failed\n"); + goto err_release_reg; } gpio_direction_output(data->pdata->gpio_sck, 0); + ret = gpio_request(data->pdata->gpio_data, "SHT15 data"); if (ret) { - dev_err(&pdev->dev, "gpio request failed"); + dev_err(&pdev->dev, "gpio request failed\n"); goto err_release_gpio_sck; } - ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group); - if (ret) { - dev_err(&pdev->dev, "sysfs create failed"); - goto err_release_gpio_data; - } ret = request_irq(gpio_to_irq(data->pdata->gpio_data), sht15_interrupt_fired, @@ -578,30 +613,44 @@ static int __devinit sht15_probe(struct platform_device *pdev) "sht15 data", data); if (ret) { - dev_err(&pdev->dev, "failed to get irq for data line"); + dev_err(&pdev->dev, "failed to get irq for data line\n"); goto err_release_gpio_data; } disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data)); sht15_connection_reset(data); sht15_send_cmd(data, 0x1E); + ret = sysfs_create_group(&pdev->dev.kobj, &sht15_attr_group); + if (ret) { + dev_err(&pdev->dev, "sysfs create failed\n"); + goto err_release_irq; + } + data->hwmon_dev = hwmon_device_register(data->dev); if (IS_ERR(data->hwmon_dev)) { ret = PTR_ERR(data->hwmon_dev); - goto err_release_irq; + goto err_release_sysfs_group; } + return 0; +err_release_sysfs_group: + sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group); err_release_irq: free_irq(gpio_to_irq(data->pdata->gpio_data), data); err_release_gpio_data: gpio_free(data->pdata->gpio_data); err_release_gpio_sck: gpio_free(data->pdata->gpio_sck); +err_release_reg: + if (!IS_ERR(data->reg)) { + regulator_unregister_notifier(data->reg, &data->nb); + regulator_disable(data->reg); + regulator_put(data->reg); + } err_free_data: kfree(data); error_ret: - return ret; } @@ -609,8 +658,10 @@ static int __devexit sht15_remove(struct platform_device *pdev) { struct sht15_data *data = platform_get_drvdata(pdev); - /* Make sure any reads from the device are done and - * prevent new ones from beginning */ + /* + * Make sure any reads from the device are done and + * prevent new ones beginning + */ mutex_lock(&data->read_lock); hwmon_device_unregister(data->hwmon_dev); sysfs_remove_group(&pdev->dev.kobj, &sht15_attr_group); @@ -625,10 +676,10 @@ static int __devexit sht15_remove(struct platform_device *pdev) gpio_free(data->pdata->gpio_sck); mutex_unlock(&data->read_lock); kfree(data); + return 0; } - /* * sht_drivers simultaneously refers to __devinit and __devexit function * which causes spurious section mismatch warning. So use __refdata to @@ -673,7 +724,6 @@ static struct platform_driver __refdata sht_drivers[] = { }, }; - static int __init sht15_init(void) { int ret; diff --git a/include/linux/sht15.h b/include/linux/sht15.h index 046bce0..1e30214 100644 --- a/include/linux/sht15.h +++ b/include/linux/sht15.h @@ -8,14 +8,18 @@ * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. + * + * For further information, see the Documentation/hwmon/sht15 file. */ /** * struct sht15_platform_data - sht15 connectivity info - * @gpio_data: no. of gpio to which bidirectional data line is connected - * @gpio_sck: no. of gpio to which the data clock is connected. - * @supply_mv: supply voltage in mv. Overridden by regulator if available. - **/ + * @gpio_data: no. of gpio to which bidirectional data line is + * connected. + * @gpio_sck: no. of gpio to which the data clock is connected. + * @supply_mv: supply voltage in mv. Overridden by regulator if + * available. + */ struct sht15_platform_data { int gpio_data; int gpio_sck; -- 1.7.1 _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
