* [PATCH] bq2415x_charger: fix max battery regulation voltage
@ 2013-10-02 10:24 Alexandre Belloni
2013-10-15 13:56 ` Pali Rohár
0 siblings, 1 reply; 6+ messages in thread
From: Alexandre Belloni @ 2013-10-02 10:24 UTC (permalink / raw)
To: Anton Vorontsov
Cc: linux-kernel, Pali Rohár, David Woodhouse, Alexandre Belloni
As per the datasheets, maximum battery regulation voltage is 4440mV.
The formula is (voltage - offset) / step, so the maximum value is:
(4440 - 3500) / 20 = 47
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
drivers/power/bq2415x_charger.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c
index 0727f92..0aa643e 100644
--- a/drivers/power/bq2415x_charger.c
+++ b/drivers/power/bq2415x_charger.c
@@ -607,7 +607,7 @@ static int bq2415x_set_battery_regulation_voltage(struct bq2415x_device *bq,
if (val < 0)
val = 0;
- else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max value ? */
+ else if (val > 47)
return -EINVAL;
return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
--
1.8.1.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] bq2415x_charger: fix max battery regulation voltage
2013-10-02 10:24 [PATCH] bq2415x_charger: fix max battery regulation voltage Alexandre Belloni
@ 2013-10-15 13:56 ` Pali Rohár
2013-10-15 14:54 ` Alexandre Belloni
0 siblings, 1 reply; 6+ messages in thread
From: Pali Rohár @ 2013-10-15 13:56 UTC (permalink / raw)
To: Alexandre Belloni; +Cc: Anton Vorontsov, linux-kernel, David Woodhouse
[-- Attachment #1: Type: Text/Plain, Size: 1297 bytes --]
On Wednesday 02 October 2013 12:24:22 Alexandre Belloni wrote:
> As per the datasheets, maximum battery regulation voltage is
> 4440mV.
>
> The formula is (voltage - offset) / step, so the maximum value
> is: (4440 - 3500) / 20 = 47
>
> Signed-off-by: Alexandre Belloni
> <alexandre.belloni@free-electrons.com> ---
> drivers/power/bq2415x_charger.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/power/bq2415x_charger.c
> b/drivers/power/bq2415x_charger.c index 0727f92..0aa643e
> 100644
> --- a/drivers/power/bq2415x_charger.c
> +++ b/drivers/power/bq2415x_charger.c
> @@ -607,7 +607,7 @@ static int
> bq2415x_set_battery_regulation_voltage(struct bq2415x_device
> *bq,
>
> if (val < 0)
> val = 0;
> - else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max
> value ? */ + else if (val > 47)
> return -EINVAL;
>
> return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
Right, max is 47 (101111) and not 94 (1011110). But if you set
all six registers to 1 then you get 63 (111111) and not 122.
I do not know from where I got above bad values, but you should
add comment to code that according to datasheet max value is
4440mV (101111) and not 4760mV (111111).
--
Pali Rohár
pali.rohar@gmail.com
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] bq2415x_charger: fix max battery regulation voltage
2013-10-15 13:56 ` Pali Rohár
@ 2013-10-15 14:54 ` Alexandre Belloni
0 siblings, 0 replies; 6+ messages in thread
From: Alexandre Belloni @ 2013-10-15 14:54 UTC (permalink / raw)
To: Pali Rohár; +Cc: Anton Vorontsov, linux-kernel, David Woodhouse
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256
On 15/10/2013 15:56, Pali Rohár wrote:
> On Wednesday 02 October 2013 12:24:22 Alexandre Belloni wrote:
>> As per the datasheets, maximum battery regulation voltage is
>> 4440mV.
>>
>> The formula is (voltage - offset) / step, so the maximum value
>> is: (4440 - 3500) / 20 = 47
>>
>> Signed-off-by: Alexandre Belloni
>> <alexandre.belloni@free-electrons.com> ---
>> drivers/power/bq2415x_charger.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/power/bq2415x_charger.c
>> b/drivers/power/bq2415x_charger.c index 0727f92..0aa643e
>> 100644
>> --- a/drivers/power/bq2415x_charger.c
>> +++ b/drivers/power/bq2415x_charger.c
>> @@ -607,7 +607,7 @@ static int
>> bq2415x_set_battery_regulation_voltage(struct bq2415x_device
>> *bq,
>>
>> if (val < 0)
>> val = 0;
>> - else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max
>> value ? */ + else if (val > 47)
>> return -EINVAL;
>>
>> return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
>
> Right, max is 47 (101111) and not 94 (1011110). But if you set
> all six registers to 1 then you get 63 (111111) and not 122.
>
> I do not know from where I got above bad values, but you should
> add comment to code that according to datasheet max value is
> 4440mV (101111) and not 4760mV (111111).
>
You probably missed the division by 2. BTW, I much prefer int val = (mV
- 3500) / 20;
which is clearer: offset is 3500mV and step is 20mV. I find your
calculation quite weird ;)
I'll send V2 with a comment then. Thank you for your review.
- --
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] bq2415x_charger: fix max battery regulation voltage
@ 2013-10-16 14:08 Alexandre Belloni
2013-10-16 14:09 ` Alexandre Belloni
0 siblings, 1 reply; 6+ messages in thread
From: Alexandre Belloni @ 2013-10-16 14:08 UTC (permalink / raw)
To: Anton Vorontsov
Cc: linux-kernel, Pali Rohár, David Woodhouse, Alexandre Belloni
As per the datasheets, maximum battery regulation voltage is 4440mV.
The formula is (voltage - offset) / step, so the maximum value is:
(4440 - 3500) / 20 = 47
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
---
drivers/power/bq2415x_charger.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c
index 0727f92..df893dd 100644
--- a/drivers/power/bq2415x_charger.c
+++ b/drivers/power/bq2415x_charger.c
@@ -605,9 +605,13 @@ static int bq2415x_set_battery_regulation_voltage(struct bq2415x_device *bq,
{
int val = (mV/10 - 350) / 2;
+ /*
+ * According to datasheet, maximum battery regulation voltage is
+ * 4440mV which is b101111 = 47.
+ */
if (val < 0)
val = 0;
- else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max value ? */
+ else if (val > 47)
return -EINVAL;
return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
--
1.8.1.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] bq2415x_charger: fix max battery regulation voltage
2013-10-16 14:08 Alexandre Belloni
@ 2013-10-16 14:09 ` Alexandre Belloni
2013-10-25 23:25 ` Anton Vorontsov
0 siblings, 1 reply; 6+ messages in thread
From: Alexandre Belloni @ 2013-10-16 14:09 UTC (permalink / raw)
To: Alexandre Belloni, Anton Vorontsov
Cc: linux-kernel, Pali Rohár, David Woodhouse
Hi,
I forgot to add this is a v2 and I just added a comment.
On 16/10/2013 16:08, Alexandre Belloni wrote:
> As per the datasheets, maximum battery regulation voltage is 4440mV.
>
> The formula is (voltage - offset) / step, so the maximum value is:
> (4440 - 3500) / 20 = 47
>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> ---
> drivers/power/bq2415x_charger.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/power/bq2415x_charger.c b/drivers/power/bq2415x_charger.c
> index 0727f92..df893dd 100644
> --- a/drivers/power/bq2415x_charger.c
> +++ b/drivers/power/bq2415x_charger.c
> @@ -605,9 +605,13 @@ static int bq2415x_set_battery_regulation_voltage(struct bq2415x_device *bq,
> {
> int val = (mV/10 - 350) / 2;
>
> + /*
> + * According to datasheet, maximum battery regulation voltage is
> + * 4440mV which is b101111 = 47.
> + */
> if (val < 0)
> val = 0;
> - else if (val > 94) /* FIXME: Max is 94 or 122 ? Set max value ? */
> + else if (val > 47)
> return -EINVAL;
>
> return bq2415x_i2c_write_mask(bq, BQ2415X_REG_VOLTAGE, val,
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] bq2415x_charger: fix max battery regulation voltage
2013-10-16 14:09 ` Alexandre Belloni
@ 2013-10-25 23:25 ` Anton Vorontsov
0 siblings, 0 replies; 6+ messages in thread
From: Anton Vorontsov @ 2013-10-25 23:25 UTC (permalink / raw)
To: Alexandre Belloni; +Cc: linux-kernel, Pali Rohár, David Woodhouse
On Wed, Oct 16, 2013 at 04:09:40PM +0200, Alexandre Belloni wrote:
> I forgot to add this is a v2 and I just added a comment.
>
> On 16/10/2013 16:08, Alexandre Belloni wrote:
> > As per the datasheets, maximum battery regulation voltage is 4440mV.
> >
> > The formula is (voltage - offset) / step, so the maximum value is:
> > (4440 - 3500) / 20 = 47
> >
> > Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Applied, thanks!
Anton
^ permalink raw reply [flat|nested] 6+ messages in thread
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2013-10-02 10:24 [PATCH] bq2415x_charger: fix max battery regulation voltage Alexandre Belloni
2013-10-15 13:56 ` Pali Rohár
2013-10-15 14:54 ` Alexandre Belloni
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2013-10-16 14:09 ` Alexandre Belloni
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