leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

hwmon: (bt1-pvt) Wait for the completion with timeout

Browse Source 
If the PVT sensor is suddenly powered down while a caller is waiting for
the conversion completion, the request won't be finished and the task will
hang up on this procedure until the power is back up again. Let's call the
wait_for_completion_timeout() method instead to prevent that. The cached
timeout is exactly what we need to predict for how long conversion could
normally last.

Fixes: 87976ce282 ("hwmon: Add Baikal-T1 PVT sensor driver")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20200920110924.19741-4-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Serge Semin 2020-09-20 14:09:23 +03:00 committed by Guenter Roeck
parent 0015503e5f
commit 0ffd21d598
1 changed files with 12 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/hwmon/bt1-pvt.c
View File

@ -477,6 +477,7 @@ static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
long *val) long *val)
{ {
struct pvt_cache *cache = &pvt->cache[type]; struct pvt_cache *cache = &pvt->cache[type];
unsigned long timeout;
u32 data; u32 data;
int ret; int ret;
@ -500,7 +501,14 @@ static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0); pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, 0);
pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN); pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, PVT_CTRL_EN);
wait_for_completion(&cache->conversion); /*
* Wait with timeout since in case if the sensor is suddenly powered
* down the request won't be completed and the caller will hang up on
* this procedure until the power is back up again. Multiply the
* timeout by the factor of two to prevent a false timeout.
*/
timeout = 2 * usecs_to_jiffies(ktime_to_us(pvt->timeout));
ret = wait_for_completion_timeout(&cache->conversion, timeout);
pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0); pvt_update(pvt->regs + PVT_CTRL, PVT_CTRL_EN, 0);
pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID, pvt_update(pvt->regs + PVT_INTR_MASK, PVT_INTR_DVALID,
@ -510,6 +518,9 @@ static int pvt_read_data(struct pvt_hwmon *pvt, enum pvt_sensor_type type,
mutex_unlock(&pvt->iface_mtx); mutex_unlock(&pvt->iface_mtx);
if (!ret)
return -ETIMEDOUT;
if (type == PVT_TEMP) if (type == PVT_TEMP)
*val = pvt_calc_poly(&poly_N_to_temp, data); *val = pvt_calc_poly(&poly_N_to_temp, data);
else else