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SubjectRe: [PATCH] regulator: s2mps11: Fix invalid minimal selector for buck9 supplying SD card
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On 28.03.2016 10:59, Javier Martinez Canillas wrote:
> Hello Krzysztof,
>
> On 03/27/2016 08:54 PM, Krzysztof Kozlowski wrote:
>> The buck9 regulator of S2MPS11 PMIC lacked minimal selector for linear
>> mapping. The mapping starts from 0x40 (3 V).
>>
>
> This patch is a real fix since the the SD error goes away and the regulator
> driver probes correctly now.
>
>> This buck9 provides power to other regulators, including LDO13 and LDO19
>> which supply the MMC2 (SD card).
>>
>
> I think it's worth mentioning that this is the case for the Exynos5422 Odroid
> XU{3,4} boards. I mean, the regulators can be used for anything but are those
> boards that use LDO19 as the SD card supply.

Yes, indeed. I forgot to add that details.

>
> In fact, I wonder if the subject line shouldn't be changed to something like:
>
> "regulator: s2mps11: Fix invalid min selector and voltages num for buck9"
>
> since the real problem is that the .linear_min_sel and .n_voltages are wrong.
> The fact that the SD was failing on Odroids is just a consequence of that
> (although I agree that this information should be part of the commit message).

Okay, seems more accurate.

>
>> Bootloader initializes the regulator with value of 0xff (5 V) which is
>> outside of supported voltage range. When (during boot) constraints to
>> buck9 were applied, the driver wrote value counting from 0x00, not 0x40.
>> Effectively driver set lower voltage than required leading to SD card
>> detection errors on Odroid XU3/XU4:
>> mmc1: card never left busy state
>> mmc1: error -110 whilst initialising SD card
>>
>> Fixes: cb74685ecb39 ("regulator: s2mps11: Add samsung s2mps11 regulator driver")
>> Cc: <stable@vger.kernel.org>
>> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
>>
>> ---
>>
>> The issue can be reproduced on next-20160324 with
>> bae4fdc88d7f7dda1 (regulator: core: Ensure we are at least in bounds
>> for our constraints).
>> ---
>> drivers/regulator/s2mps11.c | 19 ++++++++++++++++++-
>> include/linux/mfd/samsung/s2mps11.h | 9 +++++++++
>> 2 files changed, 27 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/regulator/s2mps11.c b/drivers/regulator/s2mps11.c
>> index d24e2c783dc5..caeefc38ac47 100644
>> --- a/drivers/regulator/s2mps11.c
>> +++ b/drivers/regulator/s2mps11.c
>> @@ -324,6 +324,23 @@ static struct regulator_ops s2mps11_buck_ops = {
>> .enable_mask = S2MPS11_ENABLE_MASK \
>> }
>>
>> +#define regulator_desc_s2mps11_buck9 { \
>> + .name = "BUCK9", \
>> + .id = S2MPS11_BUCK9, \
>> + .ops = &s2mps11_buck_ops, \
>> + .type = REGULATOR_VOLTAGE, \
>> + .owner = THIS_MODULE, \
>> + .min_uV = MIN_3000_MV, \
>> + .uV_step = STEP_25_MV, \
>> + .linear_min_sel = S2MPS11_BUCK9_MIN_VSEL, \
>
> I don't have a datasheet for this PMIC but I wonder if buck9 is the only
> buck regulator whose minimal register value is != 0. If that's not the
> case, it would be good to fix the descriptions for all other regulators.

Some of them are broken, some not. :) Buck 1-4 and 6 also should have
minimal selector. Also number of selectors and masks seems to be
invalid. I already have a plan to fix this up but it is not an urgent
task because the driver works so far.

>
>> + .n_voltages = S2MPS11_BUCK9_N_VOLTAGES, \
>> + .ramp_delay = S2MPS11_RAMP_DELAY, \
>> + .vsel_reg = S2MPS11_REG_B9CTRL2, \
>> + .vsel_mask = S2MPS11_BUCK_VSEL_MASK, \
>> + .enable_reg = S2MPS11_REG_B9CTRL1, \
>> + .enable_mask = S2MPS11_ENABLE_MASK \
>> +}
>> +
>> static const struct regulator_desc s2mps11_regulators[] = {
>> regulator_desc_s2mps11_ldo(1, STEP_25_MV),
>> regulator_desc_s2mps11_ldo(2, STEP_50_MV),
>> @@ -371,7 +388,7 @@ static const struct regulator_desc s2mps11_regulators[] = {
>> regulator_desc_s2mps11_buck6_10(6, MIN_600_MV, STEP_6_25_MV),
>> regulator_desc_s2mps11_buck6_10(7, MIN_600_MV, STEP_6_25_MV),
>> regulator_desc_s2mps11_buck6_10(8, MIN_600_MV, STEP_6_25_MV),
>> - regulator_desc_s2mps11_buck6_10(9, MIN_3000_MV, STEP_25_MV),
>
> Maybe the regulator_desc_s2mps11_buck6_10() define should be renamed?
> Since it's no longer true that can be used for buck6-10, so the name
> is misleading now.

Sure.

>
> Patch looks good to me though and as I said it fixes the issue so:
>
> Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>

Thanks!

I'll update patch as you suggested and re-spin with tags.

Best regards,
Krzysztof

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