diff options
Diffstat (limited to 'drivers/hwmon/chipcap2.c')
| -rw-r--r-- | drivers/hwmon/chipcap2.c | 822 |
1 files changed, 822 insertions, 0 deletions
diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c new file mode 100644 index 0000000000..6ccceae21f --- /dev/null +++ b/drivers/hwmon/chipcap2.c @@ -0,0 +1,822 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * cc2.c - Support for the Amphenol ChipCap 2 relative humidity, temperature sensor + * + * Part numbers supported: + * CC2D23, CC2D23S, CC2D25, CC2D25S, CC2D33, CC2D33S, CC2D35, CC2D35S + * + * Author: Javier Carrasco <javier.carrasco.cruz@gmail.com> + * + * Datasheet and application notes: + * https://www.amphenol-sensors.com/en/telaire/humidity/527-humidity-sensors/3095-chipcap-2 + */ + +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/hwmon.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> + +#define CC2_START_CM 0xA0 +#define CC2_START_NOM 0x80 +#define CC2_R_ALARM_H_ON 0x18 +#define CC2_R_ALARM_H_OFF 0x19 +#define CC2_R_ALARM_L_ON 0x1A +#define CC2_R_ALARM_L_OFF 0x1B +#define CC2_RW_OFFSET 0x40 +#define CC2_W_ALARM_H_ON (CC2_R_ALARM_H_ON + CC2_RW_OFFSET) +#define CC2_W_ALARM_H_OFF (CC2_R_ALARM_H_OFF + CC2_RW_OFFSET) +#define CC2_W_ALARM_L_ON (CC2_R_ALARM_L_ON + CC2_RW_OFFSET) +#define CC2_W_ALARM_L_OFF (CC2_R_ALARM_L_OFF + CC2_RW_OFFSET) + +#define CC2_STATUS_FIELD GENMASK(7, 6) +#define CC2_STATUS_VALID_DATA 0x00 +#define CC2_STATUS_STALE_DATA 0x01 +#define CC2_STATUS_CMD_MODE 0x02 + +#define CC2_RESPONSE_FIELD GENMASK(1, 0) +#define CC2_RESPONSE_BUSY 0x00 +#define CC2_RESPONSE_ACK 0x01 +#define CC2_RESPONSE_NACK 0x02 + +#define CC2_ERR_CORR_EEPROM BIT(2) +#define CC2_ERR_UNCORR_EEPROM BIT(3) +#define CC2_ERR_RAM_PARITY BIT(4) +#define CC2_ERR_CONFIG_LOAD BIT(5) + +#define CC2_EEPROM_SIZE 10 +#define CC2_EEPROM_DATA_LEN 3 +#define CC2_MEASUREMENT_DATA_LEN 4 + +#define CC2_RH_DATA_FIELD GENMASK(13, 0) + +/* ensure clean off -> on transitions */ +#define CC2_POWER_CYCLE_MS 80 + +#define CC2_STARTUP_TO_DATA_MS 55 +#define CC2_RESP_START_CM_US 100 +#define CC2_RESP_EEPROM_R_US 100 +#define CC2_RESP_EEPROM_W_MS 12 +#define CC2_STARTUP_TIME_US 1250 + +#define CC2_RH_MAX (100 * 1000U) + +#define CC2_CM_RETRIES 5 + +struct cc2_rh_alarm_info { + bool low_alarm; + bool high_alarm; + bool low_alarm_visible; + bool high_alarm_visible; +}; + +struct cc2_data { + struct cc2_rh_alarm_info rh_alarm; + struct completion complete; + struct device *hwmon; + struct i2c_client *client; + struct mutex dev_access_lock; /* device access lock */ + struct regulator *regulator; + const char *name; + int irq_ready; + int irq_low; + int irq_high; + bool process_irqs; +}; + +enum cc2_chan_addr { + CC2_CHAN_TEMP = 0, + CC2_CHAN_HUMIDITY, +}; + +/* %RH as a per cent mille from a register value */ +static long cc2_rh_convert(u16 data) +{ + unsigned long tmp = (data & CC2_RH_DATA_FIELD) * CC2_RH_MAX; + + return tmp / ((1 << 14) - 1); +} + +/* convert %RH to a register value */ +static u16 cc2_rh_to_reg(long data) +{ + return data * ((1 << 14) - 1) / CC2_RH_MAX; +} + +/* temperature in milli degrees celsius from a register value */ +static long cc2_temp_convert(u16 data) +{ + unsigned long tmp = ((data >> 2) * 165 * 1000U) / ((1 << 14) - 1); + + return tmp - 40 * 1000U; +} + +static int cc2_enable(struct cc2_data *data) +{ + int ret; + + /* exclusive regulator, check in case a disable failed */ + if (regulator_is_enabled(data->regulator)) + return 0; + + /* clear any pending completion */ + try_wait_for_completion(&data->complete); + + ret = regulator_enable(data->regulator); + if (ret < 0) + return ret; + + usleep_range(CC2_STARTUP_TIME_US, CC2_STARTUP_TIME_US + 125); + + data->process_irqs = true; + + return 0; +} + +static void cc2_disable(struct cc2_data *data) +{ + int err; + + /* ignore alarms triggered by voltage toggling when powering up */ + data->process_irqs = false; + + /* exclusive regulator, check in case an enable failed */ + if (regulator_is_enabled(data->regulator)) { + err = regulator_disable(data->regulator); + if (err) + dev_dbg(&data->client->dev, "Failed to disable device"); + } +} + +static int cc2_cmd_response_diagnostic(struct device *dev, u8 status) +{ + int resp; + + if (FIELD_GET(CC2_STATUS_FIELD, status) != CC2_STATUS_CMD_MODE) { + dev_dbg(dev, "Command sent out of command window\n"); + return -ETIMEDOUT; + } + + resp = FIELD_GET(CC2_RESPONSE_FIELD, status); + switch (resp) { + case CC2_RESPONSE_ACK: + return 0; + case CC2_RESPONSE_BUSY: + return -EBUSY; + case CC2_RESPONSE_NACK: + if (resp & CC2_ERR_CORR_EEPROM) + dev_dbg(dev, "Command failed: corrected EEPROM\n"); + if (resp & CC2_ERR_UNCORR_EEPROM) + dev_dbg(dev, "Command failed: uncorrected EEPROM\n"); + if (resp & CC2_ERR_RAM_PARITY) + dev_dbg(dev, "Command failed: RAM parity\n"); + if (resp & CC2_ERR_RAM_PARITY) + dev_dbg(dev, "Command failed: configuration error\n"); + return -ENODATA; + default: + dev_dbg(dev, "Unknown command reply\n"); + return -EINVAL; + } +} + +static int cc2_read_command_status(struct i2c_client *client) +{ + u8 status; + int ret; + + ret = i2c_master_recv(client, &status, 1); + if (ret != 1) { + ret = ret < 0 ? ret : -EIO; + return ret; + } + + return cc2_cmd_response_diagnostic(&client->dev, status); +} + +/* + * The command mode is only accessible after sending the START_CM command in the + * first 10 ms after power-up. Only in case the command window is missed, + * CC2_CM_RETRIES retries are attempted before giving up and returning an error. + */ +static int cc2_command_mode_start(struct cc2_data *data) +{ + unsigned long timeout; + int i, ret; + + for (i = 0; i < CC2_CM_RETRIES; i++) { + ret = cc2_enable(data); + if (ret < 0) + return ret; + + ret = i2c_smbus_write_word_data(data->client, CC2_START_CM, 0); + if (ret < 0) + return ret; + + if (data->irq_ready > 0) { + timeout = usecs_to_jiffies(2 * CC2_RESP_START_CM_US); + ret = wait_for_completion_timeout(&data->complete, + timeout); + if (!ret) + return -ETIMEDOUT; + } else { + usleep_range(CC2_RESP_START_CM_US, + 2 * CC2_RESP_START_CM_US); + } + ret = cc2_read_command_status(data->client); + if (ret != -ETIMEDOUT || i == CC2_CM_RETRIES) + break; + + /* command window missed, prepare for a retry */ + cc2_disable(data); + msleep(CC2_POWER_CYCLE_MS); + } + + return ret; +} + +/* Sending a Start_NOM command finishes the command mode immediately with no + * reply and the device enters normal operation mode + */ +static int cc2_command_mode_finish(struct cc2_data *data) +{ + int ret; + + ret = i2c_smbus_write_word_data(data->client, CC2_START_NOM, 0); + if (ret < 0) + return ret; + + return 0; +} + +static int cc2_write_reg(struct cc2_data *data, u8 reg, u16 val) +{ + unsigned long timeout; + int ret; + + ret = cc2_command_mode_start(data); + if (ret < 0) + goto disable; + + cpu_to_be16s(&val); + ret = i2c_smbus_write_word_data(data->client, reg, val); + if (ret < 0) + goto disable; + + if (data->irq_ready > 0) { + timeout = msecs_to_jiffies(2 * CC2_RESP_EEPROM_W_MS); + ret = wait_for_completion_timeout(&data->complete, timeout); + if (!ret) { + ret = -ETIMEDOUT; + goto disable; + } + } else { + msleep(CC2_RESP_EEPROM_W_MS); + } + + ret = cc2_read_command_status(data->client); + +disable: + cc2_disable(data); + + return ret; +} + +static int cc2_read_reg(struct cc2_data *data, u8 reg, u16 *val) +{ + u8 buf[CC2_EEPROM_DATA_LEN]; + unsigned long timeout; + int ret; + + ret = cc2_command_mode_start(data); + if (ret < 0) + return ret; + + ret = i2c_smbus_write_word_data(data->client, reg, 0); + if (ret < 0) + return ret; + + if (data->irq_ready > 0) { + timeout = usecs_to_jiffies(2 * CC2_RESP_EEPROM_R_US); + ret = wait_for_completion_timeout(&data->complete, timeout); + if (!ret) + return -ETIMEDOUT; + + } else { + usleep_range(CC2_RESP_EEPROM_R_US, CC2_RESP_EEPROM_R_US + 10); + } + ret = i2c_master_recv(data->client, buf, CC2_EEPROM_DATA_LEN); + if (ret != CC2_EEPROM_DATA_LEN) + return ret < 0 ? ret : -EIO; + + *val = be16_to_cpup((__be16 *)&buf[1]); + + return cc2_read_command_status(data->client); +} + +static int cc2_get_reg_val(struct cc2_data *data, u8 reg, long *val) +{ + u16 reg_val; + int ret; + + ret = cc2_read_reg(data, reg, ®_val); + if (!ret) + *val = cc2_rh_convert(reg_val); + + cc2_disable(data); + + return ret; +} + +static int cc2_data_fetch(struct i2c_client *client, + enum hwmon_sensor_types type, long *val) +{ + u8 data[CC2_MEASUREMENT_DATA_LEN]; + u8 status; + int ret; + + ret = i2c_master_recv(client, data, CC2_MEASUREMENT_DATA_LEN); + if (ret != CC2_MEASUREMENT_DATA_LEN) { + ret = ret < 0 ? ret : -EIO; + return ret; + } + status = FIELD_GET(CC2_STATUS_FIELD, data[0]); + if (status == CC2_STATUS_STALE_DATA) + return -EBUSY; + + if (status != CC2_STATUS_VALID_DATA) + return -EIO; + + switch (type) { + case hwmon_humidity: + *val = cc2_rh_convert(be16_to_cpup((__be16 *)&data[0])); + break; + case hwmon_temp: + *val = cc2_temp_convert(be16_to_cpup((__be16 *)&data[2])); + break; + default: + return -EINVAL; + } + + return 0; +} + +static int cc2_read_measurement(struct cc2_data *data, + enum hwmon_sensor_types type, long *val) +{ + unsigned long timeout; + int ret; + + if (data->irq_ready > 0) { + timeout = msecs_to_jiffies(CC2_STARTUP_TO_DATA_MS * 2); + ret = wait_for_completion_timeout(&data->complete, timeout); + if (!ret) + return -ETIMEDOUT; + + } else { + msleep(CC2_STARTUP_TO_DATA_MS); + } + + ret = cc2_data_fetch(data->client, type, val); + + return ret; +} + +/* + * A measurement requires enabling the device, waiting for the automatic + * measurement to finish, reading the measurement data and disabling the device + * again. + */ +static int cc2_measurement(struct cc2_data *data, enum hwmon_sensor_types type, + long *val) +{ + int ret; + + ret = cc2_enable(data); + if (ret) + return ret; + + ret = cc2_read_measurement(data, type, val); + + cc2_disable(data); + + return ret; +} + +/* + * In order to check alarm status, the corresponding ALARM_OFF (hysteresis) + * register must be read and a new measurement must be carried out to trigger + * the alarm signals. Given that the device carries out a measurement after + * exiting the command mode, there is no need to force two power-up sequences. + * Instead, a NOM command is sent and the device is disabled after the + * measurement is read. + */ +static int cc2_read_hyst_and_measure(struct cc2_data *data, u8 reg, + long *hyst, long *measurement) +{ + u16 reg_val; + int ret; + + ret = cc2_read_reg(data, reg, ®_val); + if (ret) + goto disable; + + *hyst = cc2_rh_convert(reg_val); + + ret = cc2_command_mode_finish(data); + if (ret) + goto disable; + + ret = cc2_read_measurement(data, hwmon_humidity, measurement); + +disable: + cc2_disable(data); + + return ret; +} + +static umode_t cc2_is_visible(const void *data, enum hwmon_sensor_types type, + u32 attr, int channel) +{ + const struct cc2_data *cc2 = data; + + switch (type) { + case hwmon_humidity: + switch (attr) { + case hwmon_humidity_input: + return 0444; + case hwmon_humidity_min_alarm: + return cc2->rh_alarm.low_alarm_visible ? 0444 : 0; + case hwmon_humidity_max_alarm: + return cc2->rh_alarm.high_alarm_visible ? 0444 : 0; + case hwmon_humidity_min: + case hwmon_humidity_min_hyst: + return cc2->rh_alarm.low_alarm_visible ? 0644 : 0; + case hwmon_humidity_max: + case hwmon_humidity_max_hyst: + return cc2->rh_alarm.high_alarm_visible ? 0644 : 0; + default: + return 0; + } + case hwmon_temp: + switch (attr) { + case hwmon_temp_input: + return 0444; + default: + return 0; + } + default: + break; + } + + return 0; +} + +static irqreturn_t cc2_ready_interrupt(int irq, void *data) +{ + struct cc2_data *cc2 = data; + + if (cc2->process_irqs) + complete(&cc2->complete); + + return IRQ_HANDLED; +} + +static irqreturn_t cc2_low_interrupt(int irq, void *data) +{ + struct cc2_data *cc2 = data; + + if (cc2->process_irqs) { + hwmon_notify_event(cc2->hwmon, hwmon_humidity, + hwmon_humidity_min_alarm, CC2_CHAN_HUMIDITY); + cc2->rh_alarm.low_alarm = true; + } + + return IRQ_HANDLED; +} + +static irqreturn_t cc2_high_interrupt(int irq, void *data) +{ + struct cc2_data *cc2 = data; + + if (cc2->process_irqs) { + hwmon_notify_event(cc2->hwmon, hwmon_humidity, + hwmon_humidity_max_alarm, CC2_CHAN_HUMIDITY); + cc2->rh_alarm.high_alarm = true; + } + + return IRQ_HANDLED; +} + +static int cc2_humidity_min_alarm_status(struct cc2_data *data, long *val) +{ + long measurement, min_hyst; + int ret; + + ret = cc2_read_hyst_and_measure(data, CC2_R_ALARM_L_OFF, &min_hyst, + &measurement); + if (ret < 0) + return ret; + + if (data->rh_alarm.low_alarm) { + *val = (measurement < min_hyst) ? 1 : 0; + data->rh_alarm.low_alarm = *val; + } else { + *val = 0; + } + + return 0; +} + +static int cc2_humidity_max_alarm_status(struct cc2_data *data, long *val) +{ + long measurement, max_hyst; + int ret; + + ret = cc2_read_hyst_and_measure(data, CC2_R_ALARM_H_OFF, &max_hyst, + &measurement); + if (ret < 0) + return ret; + + if (data->rh_alarm.high_alarm) { + *val = (measurement > max_hyst) ? 1 : 0; + data->rh_alarm.high_alarm = *val; + } else { + *val = 0; + } + + return 0; +} + +static int cc2_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, + int channel, long *val) +{ + struct cc2_data *data = dev_get_drvdata(dev); + int ret = 0; + + mutex_lock(&data->dev_access_lock); + + switch (type) { + case hwmon_temp: + ret = cc2_measurement(data, type, val); + break; + case hwmon_humidity: + switch (attr) { + case hwmon_humidity_input: + ret = cc2_measurement(data, type, val); + break; + case hwmon_humidity_min: + ret = cc2_get_reg_val(data, CC2_R_ALARM_L_ON, val); + break; + case hwmon_humidity_min_hyst: + ret = cc2_get_reg_val(data, CC2_R_ALARM_L_OFF, val); + break; + case hwmon_humidity_max: + ret = cc2_get_reg_val(data, CC2_R_ALARM_H_ON, val); + break; + case hwmon_humidity_max_hyst: + ret = cc2_get_reg_val(data, CC2_R_ALARM_H_OFF, val); + break; + case hwmon_humidity_min_alarm: + ret = cc2_humidity_min_alarm_status(data, val); + break; + case hwmon_humidity_max_alarm: + ret = cc2_humidity_max_alarm_status(data, val); + break; + default: + ret = -EOPNOTSUPP; + } + break; + default: + ret = -EOPNOTSUPP; + } + + mutex_unlock(&data->dev_access_lock); + + return ret; +} + +static int cc2_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, + int channel, long val) +{ + struct cc2_data *data = dev_get_drvdata(dev); + int ret; + u16 arg; + u8 cmd; + + if (type != hwmon_humidity) + return -EOPNOTSUPP; + + if (val < 0 || val > CC2_RH_MAX) + return -EINVAL; + + mutex_lock(&data->dev_access_lock); + + switch (attr) { + case hwmon_humidity_min: + cmd = CC2_W_ALARM_L_ON; + arg = cc2_rh_to_reg(val); + ret = cc2_write_reg(data, cmd, arg); + break; + + case hwmon_humidity_min_hyst: + cmd = CC2_W_ALARM_L_OFF; + arg = cc2_rh_to_reg(val); + ret = cc2_write_reg(data, cmd, arg); + break; + + case hwmon_humidity_max: + cmd = CC2_W_ALARM_H_ON; + arg = cc2_rh_to_reg(val); + ret = cc2_write_reg(data, cmd, arg); + break; + + case hwmon_humidity_max_hyst: + cmd = CC2_W_ALARM_H_OFF; + arg = cc2_rh_to_reg(val); + ret = cc2_write_reg(data, cmd, arg); + break; + + default: + ret = -EOPNOTSUPP; + break; + } + + mutex_unlock(&data->dev_access_lock); + + return ret; +} + +static int cc2_request_ready_irq(struct cc2_data *data, struct device *dev) +{ + int ret = 0; + + data->irq_ready = fwnode_irq_get_byname(dev_fwnode(dev), "ready"); + if (data->irq_ready > 0) { + init_completion(&data->complete); + ret = devm_request_threaded_irq(dev, data->irq_ready, NULL, + cc2_ready_interrupt, + IRQF_ONESHOT | + IRQF_TRIGGER_RISING, + dev_name(dev), data); + } + + return ret; +} + +static int cc2_request_alarm_irqs(struct cc2_data *data, struct device *dev) +{ + int ret = 0; + + data->irq_low = fwnode_irq_get_byname(dev_fwnode(dev), "low"); + if (data->irq_low > 0) { + ret = devm_request_threaded_irq(dev, data->irq_low, NULL, + cc2_low_interrupt, + IRQF_ONESHOT | + IRQF_TRIGGER_RISING, + dev_name(dev), data); + if (ret) + return ret; + + data->rh_alarm.low_alarm_visible = true; + } + + data->irq_high = fwnode_irq_get_byname(dev_fwnode(dev), "high"); + if (data->irq_high > 0) { + ret = devm_request_threaded_irq(dev, data->irq_high, NULL, + cc2_high_interrupt, + IRQF_ONESHOT | + IRQF_TRIGGER_RISING, + dev_name(dev), data); + if (ret) + return ret; + + data->rh_alarm.high_alarm_visible = true; + } + + return ret; +} + +static const struct hwmon_channel_info *cc2_info[] = { + HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT), + HWMON_CHANNEL_INFO(humidity, HWMON_H_INPUT | HWMON_H_MIN | HWMON_H_MAX | + HWMON_H_MIN_HYST | HWMON_H_MAX_HYST | + HWMON_H_MIN_ALARM | HWMON_H_MAX_ALARM), + NULL +}; + +static const struct hwmon_ops cc2_hwmon_ops = { + .is_visible = cc2_is_visible, + .read = cc2_read, + .write = cc2_write, +}; + +static const struct hwmon_chip_info cc2_chip_info = { + .ops = &cc2_hwmon_ops, + .info = cc2_info, +}; + +static int cc2_probe(struct i2c_client *client) +{ + struct cc2_data *data; + struct device *dev = &client->dev; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) + return -EOPNOTSUPP; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + i2c_set_clientdata(client, data); + + mutex_init(&data->dev_access_lock); + + data->client = client; + + data->regulator = devm_regulator_get_exclusive(dev, "vdd"); + if (IS_ERR(data->regulator)) { + dev_err_probe(dev, PTR_ERR(data->regulator), + "Failed to get regulator\n"); + return PTR_ERR(data->regulator); + } + + ret = cc2_request_ready_irq(data, dev); + if (ret) { + dev_err_probe(dev, ret, "Failed to request ready irq\n"); + return ret; + } + + ret = cc2_request_alarm_irqs(data, dev); + if (ret) { + dev_err_probe(dev, ret, "Failed to request alarm irqs\n"); + goto disable; + } + + data->hwmon = devm_hwmon_device_register_with_info(dev, client->name, + data, &cc2_chip_info, + NULL); + if (IS_ERR(data->hwmon)) { + dev_err_probe(dev, PTR_ERR(data->hwmon), + "Failed to register hwmon device\n"); + ret = PTR_ERR(data->hwmon); + } + +disable: + cc2_disable(data); + + return ret; +} + +static void cc2_remove(struct i2c_client *client) +{ + struct cc2_data *data = i2c_get_clientdata(client); + + cc2_disable(data); +} + +static const struct i2c_device_id cc2_id[] = { + { "cc2d23" }, + { "cc2d23s" }, + { "cc2d25" }, + { "cc2d25s" }, + { "cc2d33" }, + { "cc2d33s" }, + { "cc2d35" }, + { "cc2d35s" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, cc2_id); + +static const struct of_device_id cc2_of_match[] = { + { .compatible = "amphenol,cc2d23" }, + { .compatible = "amphenol,cc2d23s" }, + { .compatible = "amphenol,cc2d25" }, + { .compatible = "amphenol,cc2d25s" }, + { .compatible = "amphenol,cc2d33" }, + { .compatible = "amphenol,cc2d33s" }, + { .compatible = "amphenol,cc2d35" }, + { .compatible = "amphenol,cc2d35s" }, + { }, +}; +MODULE_DEVICE_TABLE(of, cc2_of_match); + +static struct i2c_driver cc2_driver = { + .driver = { + .name = "cc2d23", + .of_match_table = cc2_of_match, + }, + .probe = cc2_probe, + .remove = cc2_remove, + .id_table = cc2_id, +}; +module_i2c_driver(cc2_driver); + +MODULE_AUTHOR("Javier Carrasco <javier.carrasco.cruz@gamil.com>"); +MODULE_DESCRIPTION("Amphenol ChipCap 2 humidity and temperature sensor driver"); +MODULE_LICENSE("GPL"); |