[PATCH] regulator: s2mps11: Fix invalid minimal selector for buck9 supplying SD card

[Krzysztof Kozlowski]

The buck9 regulator of S2MPS11 PMIC lacked minimal selector for linear
mapping. The mapping starts from 0x40 (3 V).

This buck9 provides power to other regulators, including LDO13 and LDO19
which supply the MMC2 (SD card).

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: <sta...@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <k.koz...@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, \
+ .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),
+ regulator_desc_s2mps11_buck9,
regulator_desc_s2mps11_buck6_10(10, MIN_750_MV, STEP_12_5_MV),
};

diff --git a/include/linux/mfd/samsung/s2mps11.h b/include/linux/mfd/samsung/s2mps11.h
index b288965e8101..3937a932bfe0 100644
--- a/include/linux/mfd/samsung/s2mps11.h
+++ b/include/linux/mfd/samsung/s2mps11.h
@@ -173,10 +173,19 @@ enum s2mps11_regulators {

#define S2MPS11_LDO_VSEL_MASK 0x3F
#define S2MPS11_BUCK_VSEL_MASK 0xFF
+#define S2MPS11_BUCK9_MIN_VSEL 0x40
#define S2MPS11_ENABLE_MASK (0x03 << S2MPS11_ENABLE_SHIFT)
#define S2MPS11_ENABLE_SHIFT 0x06
#define S2MPS11_LDO_N_VOLTAGES (S2MPS11_LDO_VSEL_MASK + 1)
#define S2MPS11_BUCK_N_VOLTAGES (S2MPS11_BUCK_VSEL_MASK + 1)
+/*
+ * Buck9 supports only 32 voltages (values from 0x40 to 0x5F) but bootloader
+ * initializes the register with value of 0xff so when probing this would
+ * cause a failure (Odroid XU3):
+ * vdd_2.8v_ldo: failed to get the current voltage(-22)
+ * Instead pretend we support up to 0xff (5 V).
+ */
+#define S2MPS11_BUCK9_N_VOLTAGES 192
#define S2MPS11_RAMP_DELAY 25000 /* uV/us */

#define S2MPS11_CTRL1_PWRHOLD_MASK BIT(4)
--
2.5.0

[Javier Martinez Canillas]

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.

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).

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.

> + .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.

Patch looks good to me though and as I said it fixes the issue so:

Reviewed-by: Javier Martinez Canillas <jav...@osg.samsung.com>
Tested-by: Javier Martinez Canillas <jav...@osg.samsung.com>

Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America

[Krzysztof Kozlowski]

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.

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 <jav...@osg.samsung.com>
> Tested-by: Javier Martinez Canillas <jav...@osg.samsung.com>

Thanks!

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

Best regards,
Krzysztof

[Anand Moon]

Hi Krzysztof

Should their be a fix in the u-boot for HK for this issue ?
mmc card detection logic is pretty old in HK u-boot.

Best Regards
-Anand Moon

> --
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[Krzysztof Kozlowski]

On 28.03.2016 14:35, Anand Moon wrote:
> Should their be a fix in the u-boot for HK for this issue ?

It depends whether U-Boot S2MPS11 driver has this bug or has not. I did
not observe any issues with U-Boot at this matter.

> mmc card detection logic is pretty old in HK u-boot.

This is not related to MMC card detection logic.

Best regards,
Krzysztof

[Lee Jones]

On Mon, 28 Mar 2016, Krzysztof Kozlowski wrote:

> The buck9 regulator of S2MPS11 PMIC lacked minimal selector for linear
> mapping. The mapping starts from 0x40 (3 V).
>
> This buck9 provides power to other regulators, including LDO13 and LDO19
> which supply the MMC2 (SD card).
>
> 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: <sta...@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <k.koz...@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/include/linux/mfd/samsung/s2mps11.h b/include/linux/mfd/samsung/s2mps11.h
> index b288965e8101..3937a932bfe0 100644
> --- a/include/linux/mfd/samsung/s2mps11.h
> +++ b/include/linux/mfd/samsung/s2mps11.h
> @@ -173,10 +173,19 @@ enum s2mps11_regulators {
>
> #define S2MPS11_LDO_VSEL_MASK 0x3F
> #define S2MPS11_BUCK_VSEL_MASK 0xFF
> +#define S2MPS11_BUCK9_MIN_VSEL 0x40
> #define S2MPS11_ENABLE_MASK (0x03 << S2MPS11_ENABLE_SHIFT)
> #define S2MPS11_ENABLE_SHIFT 0x06
> #define S2MPS11_LDO_N_VOLTAGES (S2MPS11_LDO_VSEL_MASK + 1)
> #define S2MPS11_BUCK_N_VOLTAGES (S2MPS11_BUCK_VSEL_MASK + 1)
> +/*
> + * Buck9 supports only 32 voltages (values from 0x40 to 0x5F) but bootloader
> + * initializes the register with value of 0xff so when probing this would
> + * cause a failure (Odroid XU3):
> + * vdd_2.8v_ldo: failed to get the current voltage(-22)
> + * Instead pretend we support up to 0xff (5 V).
> + */
> +#define S2MPS11_BUCK9_N_VOLTAGES 192

Err... NACK.

Please go and fix the bootloader instead of hacking the kernel.

> #define S2MPS11_RAMP_DELAY 25000 /* uV/us */
>
> #define S2MPS11_CTRL1_PWRHOLD_MASK BIT(4)

--

Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[Krzysztof Kozlowski]

The change is not needed and was an effect of my inaccurate
understanding of device and driver behaviour. In v2 there is no such
statement and changes. Instead driver properly uses the mask without
touching other parts of register.

Best regards,
Krzysztof

[Lee Jones]

Very well. Thanks for letting me know.