linux/drivers/hwmon/chipcap2.c
Javier Carrasco efd49b8eef hwmon: (chipcap2) fix return path in cc2_request_alarm_irqs()
The return path can be improved by returning upon first failure. The
current implementation would try to register the second interrupt even
if the first one failed, which is unnecessary.

Moreover, if no irqs are available, the return value should be zero
(the driver supports the use case with no interrupts). Currently the
initial value is unassigned and that may lead to returning an unknown
value if stack variables are not automatically set to zero and no irqs
were provided.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/linux-hwmon/294e4634-89d4-415e-a723-b208d8770d7c@gmail.com/T/#t
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240207-chipcap2_init_vars-v1-2-08cafe43e20e@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2024-02-25 12:37:42 -08:00

823 lines
18 KiB
C

// 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, &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, &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");