mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 13:51:44 +00:00
hwmon: (sht15) check GPIO directions
Without this patch, the SHT15 driver may fail silently with a non-bidirectional data line and/or an input-only clock line. This patch checks the return value of gpio_direction_* function calls and returns the error code (if any) to the caller. If an error occurs in the read work function (work_funct_t), we wake the queue up directly without updating the data->state flag, to notice the waiter of the I/O error. The patch also makes minor cleanups: s/error_ret/unlock for some labels and uses devm_gpio_request_one() for the clock line. Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Vivien Didelot
Guenter Roeck
parent
9e3970fba9
commit
412e29c135
@ -212,11 +212,13 @@ static u8 sht15_crc8(struct sht15_data *data,
|
||||
*
|
||||
* This implements section 3.4 of the data sheet
|
||||
*/
|
||||
static void sht15_connection_reset(struct sht15_data *data)
|
||||
static int sht15_connection_reset(struct sht15_data *data)
|
||||
{
|
||||
int i;
|
||||
int i, err;
|
||||
|
||||
gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
err = gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
if (err)
|
||||
return err;
|
||||
ndelay(SHT15_TSCKL);
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
ndelay(SHT15_TSCKL);
|
||||
@ -226,6 +228,7 @@ static void sht15_connection_reset(struct sht15_data *data)
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
ndelay(SHT15_TSCKL);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -251,10 +254,14 @@ static inline void sht15_send_bit(struct sht15_data *data, int val)
|
||||
* conservative ones used in implementation. This implements
|
||||
* figure 12 on the data sheet.
|
||||
*/
|
||||
static void sht15_transmission_start(struct sht15_data *data)
|
||||
static int sht15_transmission_start(struct sht15_data *data)
|
||||
{
|
||||
int err;
|
||||
|
||||
/* ensure data is high and output */
|
||||
gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
err = gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
if (err)
|
||||
return err;
|
||||
ndelay(SHT15_TSU);
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
ndelay(SHT15_TSCKL);
|
||||
@ -270,6 +277,7 @@ static void sht15_transmission_start(struct sht15_data *data)
|
||||
ndelay(SHT15_TSU);
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
ndelay(SHT15_TSCKL);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -293,13 +301,19 @@ static void sht15_send_byte(struct sht15_data *data, u8 byte)
|
||||
*/
|
||||
static int sht15_wait_for_response(struct sht15_data *data)
|
||||
{
|
||||
gpio_direction_input(data->pdata->gpio_data);
|
||||
int err;
|
||||
|
||||
err = gpio_direction_input(data->pdata->gpio_data);
|
||||
if (err)
|
||||
return err;
|
||||
gpio_set_value(data->pdata->gpio_sck, 1);
|
||||
ndelay(SHT15_TSCKH);
|
||||
if (gpio_get_value(data->pdata->gpio_data)) {
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
dev_err(data->dev, "Command not acknowledged\n");
|
||||
sht15_connection_reset(data);
|
||||
err = sht15_connection_reset(data);
|
||||
if (err)
|
||||
return err;
|
||||
return -EIO;
|
||||
}
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
@ -317,12 +331,13 @@ static int sht15_wait_for_response(struct sht15_data *data)
|
||||
*/
|
||||
static int sht15_send_cmd(struct sht15_data *data, u8 cmd)
|
||||
{
|
||||
int ret = 0;
|
||||
int err;
|
||||
|
||||
sht15_transmission_start(data);
|
||||
err = sht15_transmission_start(data);
|
||||
if (err)
|
||||
return err;
|
||||
sht15_send_byte(data, cmd);
|
||||
ret = sht15_wait_for_response(data);
|
||||
return ret;
|
||||
return sht15_wait_for_response(data);
|
||||
}
|
||||
|
||||
/**
|
||||
@ -352,9 +367,13 @@ static int sht15_soft_reset(struct sht15_data *data)
|
||||
* Each byte of data is acknowledged by pulling the data line
|
||||
* low for one clock pulse.
|
||||
*/
|
||||
static void sht15_ack(struct sht15_data *data)
|
||||
static int sht15_ack(struct sht15_data *data)
|
||||
{
|
||||
gpio_direction_output(data->pdata->gpio_data, 0);
|
||||
int err;
|
||||
|
||||
err = gpio_direction_output(data->pdata->gpio_data, 0);
|
||||
if (err)
|
||||
return err;
|
||||
ndelay(SHT15_TSU);
|
||||
gpio_set_value(data->pdata->gpio_sck, 1);
|
||||
ndelay(SHT15_TSU);
|
||||
@ -362,7 +381,7 @@ static void sht15_ack(struct sht15_data *data)
|
||||
ndelay(SHT15_TSU);
|
||||
gpio_set_value(data->pdata->gpio_data, 1);
|
||||
|
||||
gpio_direction_input(data->pdata->gpio_data);
|
||||
return gpio_direction_input(data->pdata->gpio_data);
|
||||
}
|
||||
|
||||
/**
|
||||
@ -371,14 +390,19 @@ static void sht15_ack(struct sht15_data *data)
|
||||
*
|
||||
* This is basically a NAK (single clock pulse, data high).
|
||||
*/
|
||||
static void sht15_end_transmission(struct sht15_data *data)
|
||||
static int sht15_end_transmission(struct sht15_data *data)
|
||||
{
|
||||
gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
int err;
|
||||
|
||||
err = gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
if (err)
|
||||
return err;
|
||||
ndelay(SHT15_TSU);
|
||||
gpio_set_value(data->pdata->gpio_sck, 1);
|
||||
ndelay(SHT15_TSCKH);
|
||||
gpio_set_value(data->pdata->gpio_sck, 0);
|
||||
ndelay(SHT15_TSCKL);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
@ -410,17 +434,19 @@ static u8 sht15_read_byte(struct sht15_data *data)
|
||||
*/
|
||||
static int sht15_send_status(struct sht15_data *data, u8 status)
|
||||
{
|
||||
int ret;
|
||||
int err;
|
||||
|
||||
ret = sht15_send_cmd(data, SHT15_WRITE_STATUS);
|
||||
if (ret)
|
||||
return ret;
|
||||
gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
err = sht15_send_cmd(data, SHT15_WRITE_STATUS);
|
||||
if (err)
|
||||
return err;
|
||||
err = gpio_direction_output(data->pdata->gpio_data, 1);
|
||||
if (err)
|
||||
return err;
|
||||
ndelay(SHT15_TSU);
|
||||
sht15_send_byte(data, status);
|
||||
ret = sht15_wait_for_response(data);
|
||||
if (ret)
|
||||
return ret;
|
||||
err = sht15_wait_for_response(data);
|
||||
if (err)
|
||||
return err;
|
||||
|
||||
data->val_status = status;
|
||||
return 0;
|
||||
@ -446,7 +472,7 @@ static int sht15_update_status(struct sht15_data *data)
|
||||
|| !data->status_valid) {
|
||||
ret = sht15_send_cmd(data, SHT15_READ_STATUS);
|
||||
if (ret)
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
status = sht15_read_byte(data);
|
||||
|
||||
if (data->checksumming) {
|
||||
@ -458,7 +484,9 @@ static int sht15_update_status(struct sht15_data *data)
|
||||
== dev_checksum);
|
||||
}
|
||||
|
||||
sht15_end_transmission(data);
|
||||
ret = sht15_end_transmission(data);
|
||||
if (ret)
|
||||
goto unlock;
|
||||
|
||||
/*
|
||||
* Perform checksum validation on the received data.
|
||||
@ -469,27 +497,27 @@ static int sht15_update_status(struct sht15_data *data)
|
||||
previous_config = data->val_status & 0x07;
|
||||
ret = sht15_soft_reset(data);
|
||||
if (ret)
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
if (previous_config) {
|
||||
ret = sht15_send_status(data, previous_config);
|
||||
if (ret) {
|
||||
dev_err(data->dev,
|
||||
"CRC validation failed, unable "
|
||||
"to restore device settings\n");
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
}
|
||||
}
|
||||
ret = -EAGAIN;
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
}
|
||||
|
||||
data->val_status = status;
|
||||
data->status_valid = true;
|
||||
data->last_status = jiffies;
|
||||
}
|
||||
error_ret:
|
||||
mutex_unlock(&data->read_lock);
|
||||
|
||||
unlock:
|
||||
mutex_unlock(&data->read_lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -511,7 +539,9 @@ static int sht15_measurement(struct sht15_data *data,
|
||||
if (ret)
|
||||
return ret;
|
||||
|
||||
gpio_direction_input(data->pdata->gpio_data);
|
||||
ret = gpio_direction_input(data->pdata->gpio_data);
|
||||
if (ret)
|
||||
return ret;
|
||||
atomic_set(&data->interrupt_handled, 0);
|
||||
|
||||
enable_irq(gpio_to_irq(data->pdata->gpio_data));
|
||||
@ -524,9 +554,14 @@ static int sht15_measurement(struct sht15_data *data,
|
||||
ret = wait_event_timeout(data->wait_queue,
|
||||
(data->state == SHT15_READING_NOTHING),
|
||||
msecs_to_jiffies(timeout_msecs));
|
||||
if (ret == 0) {/* timeout occurred */
|
||||
if (data->state != SHT15_READING_NOTHING) { /* I/O error occurred */
|
||||
data->state = SHT15_READING_NOTHING;
|
||||
return -EIO;
|
||||
} else if (ret == 0) { /* timeout occurred */
|
||||
disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data));
|
||||
sht15_connection_reset(data);
|
||||
ret = sht15_connection_reset(data);
|
||||
if (ret)
|
||||
return ret;
|
||||
return -ETIME;
|
||||
}
|
||||
|
||||
@ -570,17 +605,17 @@ static int sht15_update_measurements(struct sht15_data *data)
|
||||
data->state = SHT15_READING_HUMID;
|
||||
ret = sht15_measurement(data, SHT15_MEASURE_RH, 160);
|
||||
if (ret)
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
data->state = SHT15_READING_TEMP;
|
||||
ret = sht15_measurement(data, SHT15_MEASURE_TEMP, 400);
|
||||
if (ret)
|
||||
goto error_ret;
|
||||
goto unlock;
|
||||
data->measurements_valid = true;
|
||||
data->last_measurement = jiffies;
|
||||
}
|
||||
error_ret:
|
||||
mutex_unlock(&data->read_lock);
|
||||
|
||||
unlock:
|
||||
mutex_unlock(&data->read_lock);
|
||||
return ret;
|
||||
}
|
||||
|
||||
@ -818,7 +853,8 @@ static void sht15_bh_read_data(struct work_struct *work_s)
|
||||
/* Read the data back from the device */
|
||||
val = sht15_read_byte(data);
|
||||
val <<= 8;
|
||||
sht15_ack(data);
|
||||
if (sht15_ack(data))
|
||||
goto wakeup;
|
||||
val |= sht15_read_byte(data);
|
||||
|
||||
if (data->checksumming) {
|
||||
@ -826,7 +862,8 @@ static void sht15_bh_read_data(struct work_struct *work_s)
|
||||
* Ask the device for a checksum and read it back.
|
||||
* Note: the device sends the checksum byte reversed.
|
||||
*/
|
||||
sht15_ack(data);
|
||||
if (sht15_ack(data))
|
||||
goto wakeup;
|
||||
dev_checksum = sht15_reverse(sht15_read_byte(data));
|
||||
checksum_vals[0] = (data->state == SHT15_READING_TEMP) ?
|
||||
SHT15_MEASURE_TEMP : SHT15_MEASURE_RH;
|
||||
@ -837,7 +874,8 @@ static void sht15_bh_read_data(struct work_struct *work_s)
|
||||
}
|
||||
|
||||
/* Tell the device we are done */
|
||||
sht15_end_transmission(data);
|
||||
if (sht15_end_transmission(data))
|
||||
goto wakeup;
|
||||
|
||||
switch (data->state) {
|
||||
case SHT15_READING_TEMP:
|
||||
@ -851,6 +889,7 @@ static void sht15_bh_read_data(struct work_struct *work_s)
|
||||
}
|
||||
|
||||
data->state = SHT15_READING_NOTHING;
|
||||
wakeup:
|
||||
wake_up(&data->wait_queue);
|
||||
}
|
||||
|
||||
@ -942,17 +981,17 @@ static int sht15_probe(struct platform_device *pdev)
|
||||
}
|
||||
|
||||
/* Try requesting the GPIOs */
|
||||
ret = devm_gpio_request(&pdev->dev, data->pdata->gpio_sck, "SHT15 sck");
|
||||
ret = devm_gpio_request_one(&pdev->dev, data->pdata->gpio_sck,
|
||||
GPIOF_OUT_INIT_LOW, "SHT15 sck");
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "gpio request failed\n");
|
||||
dev_err(&pdev->dev, "clock line GPIO request failed\n");
|
||||
goto err_release_reg;
|
||||
}
|
||||
gpio_direction_output(data->pdata->gpio_sck, 0);
|
||||
|
||||
ret = devm_gpio_request(&pdev->dev, data->pdata->gpio_data,
|
||||
"SHT15 data");
|
||||
if (ret) {
|
||||
dev_err(&pdev->dev, "gpio request failed\n");
|
||||
dev_err(&pdev->dev, "data line GPIO request failed\n");
|
||||
goto err_release_reg;
|
||||
}
|
||||
|
||||
@ -966,7 +1005,9 @@ static int sht15_probe(struct platform_device *pdev)
|
||||
goto err_release_reg;
|
||||
}
|
||||
disable_irq_nosync(gpio_to_irq(data->pdata->gpio_data));
|
||||
sht15_connection_reset(data);
|
||||
ret = sht15_connection_reset(data);
|
||||
if (ret)
|
||||
goto err_release_reg;
|
||||
ret = sht15_soft_reset(data);
|
||||
if (ret)
|
||||
goto err_release_reg;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user