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: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
>
> ---
>
> 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
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