4.14-stable review patch. If anyone has any objections, please let me know.
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From: Hans de Goede hdegoede@redhat.com
[ Upstream commit c975e472ec12392a0c34de1350e634310f8a1dea ]
The Point of View mobii wintab p800w Bay Trail tablet comes with a Crystal Cove PMIC, yet uses the LPSS PWM for backlight control, rather then the Crystal Cove's PWM, so we need to call pwm_add_table() to add a pwm_backlight mapping for the LPSS pwm despite there being an INT33FD ACPI device present.
On all Bay Trail devices the _HRV object of the INT33FD ACPI device will normally return 2, to indicate the Bay Trail variant of the CRC PMIC is present, except on this tablet where _HRV is 0xffff. I guess this is a hack to make the windows Crystal Cove PWM driver not bind.
Out of the 44 DSTDs with an INT33FD device in there which I have (from different model devices) only the pov mobii wintab p800w uses 0xffff for the HRV.
The byt_pwm_setup code calls acpi_dev_present to check for the presence of a INT33FD ACPI device which indicates that a CRC PMIC is present and if the INT33FD ACPI device is present then byt_pwm_setup will not add a pwm_backlight mapping for the LPSS pwm, so that the CRC PWM will get used instead.
acpi_dev_present has a hrv parameter, this commit make us pass 2 instead of -1, so that things still match on normal tablets, but on this special case with its _HRV of 0xffff, the check will now fail so that the pwm_backlight mapping for the LPSS pwm gets added fixing backlight brightness control on this device.
Signed-off-by: Hans de Goede hdegoede@redhat.com Reviewed-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/acpi/acpi_lpss.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/acpi/acpi_lpss.c +++ b/drivers/acpi/acpi_lpss.c @@ -69,6 +69,10 @@ ACPI_MODULE_NAME("acpi_lpss"); #define LPSS_SAVE_CTX BIT(4) #define LPSS_NO_D3_DELAY BIT(5)
+/* Crystal Cove PMIC shares same ACPI ID between different platforms */ +#define BYT_CRC_HRV 2 +#define CHT_CRC_HRV 3 + struct lpss_private_data;
struct lpss_device_desc { @@ -162,7 +166,7 @@ static void byt_pwm_setup(struct lpss_pr if (!adev->pnp.unique_id || strcmp(adev->pnp.unique_id, "1")) return;
- if (!acpi_dev_present("INT33FD", NULL, -1)) + if (!acpi_dev_present("INT33FD", NULL, BYT_CRC_HRV)) pwm_add_table(byt_pwm_lookup, ARRAY_SIZE(byt_pwm_lookup)); }