• Hans de Goede's avatar
    mfd: axp20x: Update AXP288 volatile ranges · f949a9eb
    Hans de Goede authored
    On Cherry Trail devices with an AXP288 PMIC the external SD-card slot
    used the AXP's DLDO2 as card-voltage and either DLDO3 or GPIO1LDO
    (GPIO1 pin in low noise LDO mode) as signal-voltage.
    
    These regulators are turned on/off and in case of the signal-voltage
    also have their output-voltage changed by the _PS0 and _PS3 power-
    management ACPI methods on the MMC-controllers ACPI fwnode as well as
    by the _DSM ACPI method for changing the signal voltage.
    
    The AML code implementing these methods is directly accessing the
    PMIC through ACPI I2C OpRegion accesses, instead of using the special
    PMIC OpRegion handled by drivers/acpi/pmic/intel_pmic_xpower.c .
    
    This means that the contents of the involved PMIC registers can change
    without the change being made through the regmap interface, so regmap
    should not cache the contents of these registers.
    
    Mark the regulator power on/off, the regulator voltage control and the
    GPIO1 control registers as volatile, to avoid regmap caching them.
    
    Specifically this fixes an issue on some models where the i915 driver
    toggles another LDO using the same on/off register on/off through
    MIPI sequences (through intel_soc_pmic_exec_mipi_pmic_seq_element())
    which then writes back a cached on/off register-value where the
    card-voltage is off causing the external sdcard slot to stop working
    when the screen goes blank, or comes back on again.
    
    The regulator register-range now marked volatile also includes the
    buck regulator control registers. This is done on purpose these are
    normally not touched by the AML code, but they are updated directly
    by the SoC's PUNIT which means that they may also change without going
    through regmap.
    
    Note the AXP288 PMIC is only used on Bay- and Cherry-Trail platforms,
    so even though this is an ACPI specific problem there is no need to
    make the new volatile ranges conditional since these platforms always
    use ACPI.
    
    Fixes: dc91c3b6 ("mfd: axp20x: Mark AXP20X_VBUS_IPSOUT_MGMT as volatile")
    Fixes: cd532166 ("mfd: axp20x: Fix axp288 volatile ranges")
    Reported-and-tested-by: default avatarClamshell <clamfly@163.com>
    Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
    Reviewed-by: default avatarChen-Yu Tsai <wens@csie.org>
    Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
    f949a9eb
axp20x.c 34.3 KB