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SubjectRe: [PATCH] hwmon: (tmp102) Force wait for conversion time for the first valid data
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On 12/01/2015 06:21 AM, Nishanth Menon wrote:
[ ... ]

>
> Hint about how the patch will look like:

Looks ok (and better).

Guenter

> diff --git a/drivers/hwmon/tmp102.c b/drivers/hwmon/tmp102.c
> index 65482624ea2c..5289aa0980a8 100644
> --- a/drivers/hwmon/tmp102.c
> +++ b/drivers/hwmon/tmp102.c
> @@ -58,6 +58,7 @@ struct tmp102 {
> u16 config_orig;
> unsigned long last_update;
> int temp[3];
> + bool first_time;
> };
>
> /* convert left adjusted 13-bit TMP102 register value to milliCelsius */
> @@ -93,6 +94,7 @@ 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;
> }
> mutex_unlock(&tmp102->lock);
> return tmp102;
> @@ -102,6 +104,12 @@ static int tmp102_read_temp(void *dev, int *temp)
> {
> struct tmp102 *tmp102 = tmp102_update_device(dev);
>
> + /* Is it too early even to return a conversion? */
> + if (tmp102->first_time) {
> + dev_dbg(dev, "%s: Conversion not ready yet..\n", __func__);
> + return -EAGAIN;
> + }
> +
> *temp = tmp102->temp[0];
>
> return 0;
> @@ -114,6 +122,10 @@ static ssize_t tmp102_show_temp(struct device *dev,
> struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
> struct tmp102 *tmp102 = tmp102_update_device(dev);
>
> + /* Is it too early even to return a read? */
> + if (tmp102->first_time)
> + return -EAGAIN;
> +
> return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
> }
>
> @@ -207,7 +219,9 @@ static int tmp102_probe(struct i2c_client *client,
> status = -ENODEV;
> goto fail_restore_config;
> }
> - tmp102->last_update = jiffies - HZ;
> + tmp102->last_update = jiffies;
> + /* Mark that we are not ready with data until conversion is complete */
> + tmp102->first_time = true;
> mutex_init(&tmp102->lock);
>
> hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
>



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