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author | Guenter Roeck <linux@roeck-us.net> | 2016-06-19 20:34:57 -0700 |
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committer | Guenter Roeck <linux@roeck-us.net> | 2016-07-12 14:23:57 -0700 |
commit | 3d8f7a89a1979be7f631cf06e02f882adf144885 (patch) | |
tree | 4a041c0a793a9e20a80d9b6d5b70a7d008a2da01 /drivers/hwmon | |
parent | 589f707c72426793a0f537592098a5a2a3117dc0 (diff) | |
download | linux-stable-3d8f7a89a1979be7f631cf06e02f882adf144885.tar.gz linux-stable-3d8f7a89a1979be7f631cf06e02f882adf144885.tar.bz2 linux-stable-3d8f7a89a1979be7f631cf06e02f882adf144885.zip |
hwmon: (tmp102) Improve handling of initial read delay
If the chip was in shutdown mode when the driver was loaded, the first
conversion is ready no more than 35 milli-seconds after the chip was
taken out of shutdown. The driver delay was so far set to 333 ms (HZ / 3),
which is much higher than the maximum time needed by the chip.
Reduce the time to 35 milli-seconds.
Introduce a 'valid' flag to ensure that sensor data is actually read
even if requested less than 333 ms after the driver was loaded.
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r-- | drivers/hwmon/tmp102.c | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c index 5bdf262e6a0e..fd4a4515692a 100644 --- a/drivers/hwmon/tmp102.c +++ b/drivers/hwmon/tmp102.c @@ -13,6 +13,7 @@ * GNU General Public License for more details. */ +#include <linux/delay.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> @@ -46,13 +47,16 @@ #define TMP102_TLOW_REG 0x02 #define TMP102_THIGH_REG 0x03 +#define CONVERSION_TIME_MS 35 /* in milli-seconds */ + struct tmp102 { struct i2c_client *client; struct mutex lock; u16 config_orig; unsigned long last_update; + unsigned long ready_time; + bool valid; int temp[3]; - bool first_time; }; /* convert left adjusted 13-bit TMP102 register value to milliCelsius */ @@ -73,13 +77,14 @@ static const u8 tmp102_reg[] = { TMP102_THIGH_REG, }; -static struct tmp102 *tmp102_update_device(struct device *dev) +static void tmp102_update_device(struct device *dev) { struct tmp102 *tmp102 = dev_get_drvdata(dev); struct i2c_client *client = tmp102->client; mutex_lock(&tmp102->lock); - if (time_after(jiffies, tmp102->last_update + HZ / 3)) { + if (!tmp102->valid || + time_after(jiffies, tmp102->last_update + HZ / 3)) { int i; for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) { int status = i2c_smbus_read_word_swapped(client, @@ -88,22 +93,22 @@ static struct tmp102 *tmp102_update_device(struct device *dev) tmp102->temp[i] = tmp102_reg_to_mC(status); } tmp102->last_update = jiffies; - tmp102->first_time = false; + tmp102->valid = true; } mutex_unlock(&tmp102->lock); - return tmp102; } static int tmp102_read_temp(void *dev, int *temp) { - struct tmp102 *tmp102 = tmp102_update_device(dev); + struct tmp102 *tmp102 = dev_get_drvdata(dev); - /* Is it too early even to return a conversion? */ - if (tmp102->first_time) { + if (time_before(jiffies, tmp102->ready_time)) { dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__); return -EAGAIN; } + tmp102_update_device(dev); + *temp = tmp102->temp[0]; return 0; @@ -114,12 +119,13 @@ static ssize_t tmp102_show_temp(struct device *dev, char *buf) { struct sensor_device_attribute *sda = to_sensor_dev_attr(attr); - struct tmp102 *tmp102 = tmp102_update_device(dev); + struct tmp102 *tmp102 = dev_get_drvdata(dev); - /* Is it too early even to return a read? */ - if (tmp102->first_time) + if (time_before(jiffies, tmp102->ready_time)) return -EAGAIN; + tmp102_update_device(dev); + return sprintf(buf, "%d\n", tmp102->temp[sda->index]); } @@ -224,11 +230,18 @@ static int tmp102_probe(struct i2c_client *client, dev_err(dev, "config settings did not stick\n"); return -ENODEV; } - tmp102->last_update = jiffies; - /* Mark that we are not ready with data until conversion is complete */ - tmp102->first_time = true; + mutex_init(&tmp102->lock); + tmp102->ready_time = jiffies; + if (tmp102->config_orig & TMP102_CONF_SD) { + /* + * Mark that we are not ready with data until the first + * conversion is complete + */ + tmp102->ready_time += msecs_to_jiffies(CONVERSION_TIME_MS); + } + hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, tmp102, tmp102_groups); @@ -261,12 +274,15 @@ static int tmp102_suspend(struct device *dev) static int tmp102_resume(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); + struct tmp102 *tmp102 = i2c_get_clientdata(client); int config; config = i2c_smbus_read_word_swapped(client, TMP102_CONF_REG); if (config < 0) return config; + tmp102->ready_time = jiffies + msecs_to_jiffies(CONVERSION_TIME_MS); + config &= ~TMP102_CONF_SD; return i2c_smbus_write_word_swapped(client, TMP102_CONF_REG, config); } |