[lm-sensors] [RFC][PATCH]Add suspend and resume for LM75

[Jean Delvare]

Hi Shubhrajyoti,

On Fri, 28 May 2010 11:31:23 +0530, Datta, Shubhrajyoti wrote:
> 
> There is a shutdown feature at suspend it can be enabled
> to reduce current consumption and resume it can be switched
> off.
> 
> Signed-off-by: Shubhrajyoti D <shubhrajyoti at ti.com>

Please use your full name.

> ---
>  drivers/hwmon/lm75.c |   35 +++++++++++++++++++++++++++++++++++
>  drivers/hwmon/lm75.h |    1 +
>  2 files changed, 36 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
> index 5646342..4ef1f59 100644
> --- a/drivers/hwmon/lm75.c
> +++ b/drivers/hwmon/lm75.c
> @@ -281,6 +281,39 @@ static int lm75_detect(struct i2c_client *new_client,
>  
>  	return 0;
>  }
> +#ifdef CONFIG_PM
> +static int lm75_suspend(struct device *dev)
> +{
> +	int status;
> +	struct i2c_client *client = to_i2c_client(dev);
> +	status = lm75_read_value(client, LM75_REG_CONF);
> +	if (status < 0) {
> +		dev_dbg(&client->dev, "Can't read config? %d\n", status);
> +		return status;
> +	}
> +	status = status | LM75_SHUTDOWN;
> +	lm75_write_value(client, LM75_REG_CONF, status);
> +	return 0;
> +}
> +
> +static int lm75_resume(struct device *dev)
> +{
> +	int status;
> +	struct i2c_client *client = to_i2c_client(dev);
> +	status = lm75_read_value(client, LM75_REG_CONF);
> +	if (status < 0) {
> +		dev_dbg(&client->dev, "Can't read config? %d\n", status);
> +		return status;
> +	}
> +	status = status & ~LM75_SHUTDOWN;
> +	lm75_write_value(client, LM75_REG_CONF, status);
> +	return 0;
> +}
> +#else
> +#define lm75_suspend NULL
> +#define lm75_resume NULL
> +#endif /* CONFIG_PM */
> +
>  
>  static struct i2c_driver lm75_driver = {
>  	.class		= I2C_CLASS_HWMON,
> @@ -292,6 +325,8 @@ static struct i2c_driver lm75_driver = {
>  	.id_table	= lm75_ids,
>  	.detect		= lm75_detect,
>  	.address_list	= normal_i2c,
> +	.suspend		= lm75_suspend,
> +	.resume		= lm75_resume,

I get the following warning:

drivers/hwmon/lm75.c:326: warning: initialization from incompatible pointer type
drivers/hwmon/lm75.c:327: warning: initialization from incompatible pointer type

so it can't be right. Look in <linux/i2c.h>, these functions want
struct i2c_client as a parameter, not struct device.

>  };
>  
>  /*-----------------------------------------------------------------------*/
> diff --git a/drivers/hwmon/lm75.h b/drivers/hwmon/lm75.h
> index 7c93454..8e14253 100644
> --- a/drivers/hwmon/lm75.h
> +++ b/drivers/hwmon/lm75.h
> @@ -30,6 +30,7 @@
>  /* straight from the datasheet */
>  #define LM75_TEMP_MIN (-55000)
>  #define LM75_TEMP_MAX 125000
> +#define LM75_SHUTDOWN 1

Would be better written 0x01, as this is a bit mask.

>  
>  /* TEMP: 0.001C/bit (-55C to +125C)
>     REG: (0.5C/bit, two's complement) << 7 */


-- 
Jean Delvare