[PATCH v2 3/3] lp8788-charger: fix wrong ADC conversion

[PATCH v2 3/3] lp8788-charger: fix wrong ADC conversion

[Kim, Milo]

 To get the battery voltage and temperature, IIO ADC functions are used.
 LP8788 ADC driver provides RAW and SCALE channel information.
 This patch fixes wrong ADC result.

 Patch v2.
 Use simple iio_read_channel_processed() function rather than
 iio_read_channel_raw() and _scale().

 Fix the result type of ADC function as a signed integer.
 Because power_supply_propval.intval and the return value of
 iio_read_channel_processed() are a signed integer,
 'unsigned int' are replaced with 'int'.

 Patch v1.
 Fix wrong ADC results using iio_read_channel_raw() and _scale().

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
---
 drivers/power/lp8788-charger.c |   26 +++++++-------------------
 1 file changed, 7 insertions(+), 19 deletions(-)

diff --git a/drivers/power/lp8788-charger.c b/drivers/power/lp8788-charger.c
index 02fc9ab..f18ec8f 100644
--- a/drivers/power/lp8788-charger.c
+++ b/drivers/power/lp8788-charger.c
@@ -235,25 +235,14 @@ static int lp8788_get_battery_present(struct lp8788_charger *pchg,
 	return 0;
 }
 
-static int lp8788_get_vbatt_adc(struct lp8788_charger *pchg,
-				unsigned int *result)
+static int lp8788_get_vbatt_adc(struct lp8788_charger *pchg, int *result)
 {
 	struct iio_channel *channel = pchg->chan[LP8788_VBATT];
-	int scaleint;
-	int scalepart;
-	int ret;
 
 	if (!channel)
 		return -EINVAL;
 
-	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
-	if (ret != IIO_VAL_INT_PLUS_MICRO)
-		return -EINVAL;
-
-	/* unit: mV */
-	*result = (scaleint + scalepart * 1000000) / 1000;
-
-	return 0;
+	return iio_read_channel_processed(channel, result);
 }
 
 static int lp8788_get_battery_voltage(struct lp8788_charger *pchg,
@@ -268,7 +257,7 @@ static int lp8788_get_battery_capacity(struct lp8788_charger *pchg,
 	struct lp8788 *lp = pchg->lp;
 	struct lp8788_charger_platform_data *pdata = pchg->pdata;
 	unsigned int max_vbatt;
-	unsigned int vbatt;
+	int vbatt;
 	enum lp8788_charging_state state;
 	u8 data;
 	int ret;
@@ -304,19 +293,18 @@ static int lp8788_get_battery_temperature(struct lp8788_charger *pchg,
 				union power_supply_propval *val)
 {
 	struct iio_channel *channel = pchg->chan[LP8788_BATT_TEMP];
-	int scaleint;
-	int scalepart;
+	int result;
 	int ret;
 
 	if (!channel)
 		return -EINVAL;
 
-	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
-	if (ret != IIO_VAL_INT_PLUS_MICRO)
+	ret = iio_read_channel_processed(channel, &result);
+	if (ret < 0)
 		return -EINVAL;
 
 	/* unit: 0.1 'C */
-	val->intval = (scaleint + scalepart * 1000000) / 100;
+	val->intval = result * 10;
 
 	return 0;
 }
-- 
1.7.9.5


Best Regards,
Milo

Re: [PATCH v2 3/3] lp8788-charger: fix wrong ADC conversion

[Lars-Peter Clausen]

On 10/19/2012 02:12 AM, Kim, Milo wrote:
>  To get the battery voltage and temperature, IIO ADC functions are used.
>  LP8788 ADC driver provides RAW and SCALE channel information.
>  This patch fixes wrong ADC result.
> 
>  Patch v2.
>  Use simple iio_read_channel_processed() function rather than
>  iio_read_channel_raw() and _scale().
> 
>  Fix the result type of ADC function as a signed integer.
>  Because power_supply_propval.intval and the return value of
>  iio_read_channel_processed() are a signed integer,
>  'unsigned int' are replaced with 'int'.
> 
>  Patch v1.
>  Fix wrong ADC results using iio_read_channel_raw() and _scale().
> 
> Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>

Looks good to me, fwiw:

Reviewed-by Lars-Peter Clausen <lars@metafoo.de>

But there is one issue, but this is not necessarily related to this patch,
more inline.

> ---
>  drivers/power/lp8788-charger.c |   26 +++++++-------------------
>  1 file changed, 7 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/power/lp8788-charger.c b/drivers/power/lp8788-charger.c
> index 02fc9ab..f18ec8f 100644
> --- a/drivers/power/lp8788-charger.c
> +++ b/drivers/power/lp8788-charger.c
> @@ -235,25 +235,14 @@ static int lp8788_get_battery_present(struct lp8788_charger *pchg,
>  	return 0;
>  }
>  
[...]
>  static int lp8788_get_battery_voltage(struct lp8788_charger *pchg,
> @@ -268,7 +257,7 @@ static int lp8788_get_battery_capacity(struct lp8788_charger *pchg,
>  	struct lp8788 *lp = pchg->lp;
>  	struct lp8788_charger_platform_data *pdata = pchg->pdata;
>  	unsigned int max_vbatt;
> -	unsigned int vbatt;
> +	int vbatt;
>  	enum lp8788_charging_state state;
>  	u8 data;
>  	int ret;
> @@ -304,19 +293,18 @@ static int lp8788_get_battery_temperature(struct lp8788_charger *pchg,
>  				union power_supply_propval *val)
>  {
>  	struct iio_channel *channel = pchg->chan[LP8788_BATT_TEMP];
> -	int scaleint;
> -	int scalepart;
> +	int result;
>  	int ret;
>  
>  	if (!channel)
>  		return -EINVAL;
>  
> -	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
> -	if (ret != IIO_VAL_INT_PLUS_MICRO)
> +	ret = iio_read_channel_processed(channel, &result);
> +	if (ret < 0)
>  		return -EINVAL;
>  
>  	/* unit: 0.1 'C */
> -	val->intval = (scaleint + scalepart * 1000000) / 100;
> +	val->intval = result * 10;

IIO reports temperatures in milli degree Celsius. So it should be multiplied
by 100 to get tenth degree like the power supply framework expects it. But
this might be a issue in your IIO driver reporting the wrong scale.

- Lars

>  
>  	return 0;
>  }

Re: [PATCH v2 3/3] lp8788-charger: fix wrong ADC conversion

[Jonathan Cameron]

On 10/19/2012 01:45 PM, Lars-Peter Clausen wrote:
> On 10/19/2012 02:12 AM, Kim, Milo wrote:
>>  To get the battery voltage and temperature, IIO ADC functions are used.
>>  LP8788 ADC driver provides RAW and SCALE channel information.
>>  This patch fixes wrong ADC result.
>>
>>  Patch v2.
>>  Use simple iio_read_channel_processed() function rather than
>>  iio_read_channel_raw() and _scale().
>>
>>  Fix the result type of ADC function as a signed integer.
>>  Because power_supply_propval.intval and the return value of
>>  iio_read_channel_processed() are a signed integer,
>>  'unsigned int' are replaced with 'int'.
>>
>>  Patch v1.
>>  Fix wrong ADC results using iio_read_channel_raw() and _scale().
>>
>> Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
> 
> Looks good to me, fwiw:
> 
> Reviewed-by Lars-Peter Clausen <lars@metafoo.de>
On this stuff as far as I'm concerned Lars' approval is fine but
for what it's worth this all looks fine to me.

Acked-by: Jonathan Cameron <jic23@kernel.org>

> 
> But there is one issue, but this is not necessarily related to this patch,
> more inline.
> 
>> ---
>>  drivers/power/lp8788-charger.c |   26 +++++++-------------------
>>  1 file changed, 7 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/power/lp8788-charger.c b/drivers/power/lp8788-charger.c
>> index 02fc9ab..f18ec8f 100644
>> --- a/drivers/power/lp8788-charger.c
>> +++ b/drivers/power/lp8788-charger.c
>> @@ -235,25 +235,14 @@ static int lp8788_get_battery_present(struct lp8788_charger *pchg,
>>  	return 0;
>>  }
>>  
> [...]
>>  static int lp8788_get_battery_voltage(struct lp8788_charger *pchg,
>> @@ -268,7 +257,7 @@ static int lp8788_get_battery_capacity(struct lp8788_charger *pchg,
>>  	struct lp8788 *lp = pchg->lp;
>>  	struct lp8788_charger_platform_data *pdata = pchg->pdata;
>>  	unsigned int max_vbatt;
>> -	unsigned int vbatt;
>> +	int vbatt;
>>  	enum lp8788_charging_state state;
>>  	u8 data;
>>  	int ret;
>> @@ -304,19 +293,18 @@ static int lp8788_get_battery_temperature(struct lp8788_charger *pchg,
>>  				union power_supply_propval *val)
>>  {
>>  	struct iio_channel *channel = pchg->chan[LP8788_BATT_TEMP];
>> -	int scaleint;
>> -	int scalepart;
>> +	int result;
>>  	int ret;
>>  
>>  	if (!channel)
>>  		return -EINVAL;
>>  
>> -	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
>> -	if (ret != IIO_VAL_INT_PLUS_MICRO)
>> +	ret = iio_read_channel_processed(channel, &result);
>> +	if (ret < 0)
>>  		return -EINVAL;
>>  
>>  	/* unit: 0.1 'C */
>> -	val->intval = (scaleint + scalepart * 1000000) / 100;
>> +	val->intval = result * 10;
> 
> IIO reports temperatures in milli degree Celsius. So it should be multiplied
> by 100 to get tenth degree like the power supply framework expects it. But
> this might be a issue in your IIO driver reporting the wrong scale.
> 
> - Lars
> 
>>  
>>  	return 0;
>>  }
> 

Re: [PATCH v2 3/3] lp8788-charger: fix wrong ADC conversion

[Anton Vorontsov]

On Fri, Nov 02, 2012 at 10:09:20AM +0000, Jonathan Cameron wrote:
[...]
> > Looks good to me, fwiw:
> > 
> > Reviewed-by Lars-Peter Clausen <lars@metafoo.de>
>
> On this stuff as far as I'm concerned Lars' approval is fine but
> for what it's worth this all looks fine to me.
> 
> Acked-by: Jonathan Cameron <jic23@kernel.org>

All three applied, thanks a lot!