ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices

BugLink: http://bugs.launchpad.net/bugs/1807469
commit fdcb613d49321b5bf5d5a1bd0fba8e7c241dcc70 upstream.

The LPSS PWM device on on Bay Trail and Cherry Trail devices has a set
of private registers at offset 0x800, the current lpss_device_desc for
them already sets the LPSS_SAVE_CTX flag to have these saved/restored
over device-suspend, but the current lpss_device_desc was not setting
the prv_offset field, leading to the regular device registers getting
saved/restored instead.

This is causing the PWM controller to no longer work, resulting in a black
screen,  after a suspend/resume on systems where the firmware clears the
APB clock and reset bits at offset 0x804.

This commit fixes this by properly setting prv_offset to 0x800 for
the PWM devices.

Cc: stable@vger.kernel.org
Fixes: e1c748179754 ("ACPI / LPSS: Add Intel BayTrail ACPI mode PWM")
Fixes: 1bfbd8eb8a7f ("ACPI / LPSS: Add ACPI IDs for Intel Braswell")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Rafael J . Wysocki <rjw@rjwysocki.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/acpi/acpi_lpss.c b/drivers/acpi/acpi_lpss.c
index 8e37c2317e275aed26428849d26e5b860f2d7b27..93565d3125a6a85aa2e5e8d41aed8851880fd7aa 100644 (file)
--- a/drivers/acpi/acpi_lpss.c
+++ b/drivers/acpi/acpi_lpss.c
@@ -230,11 +230,13 @@ static const struct lpss_device_desc lpt_sdio_dev_desc = {
 
 static const struct lpss_device_desc byt_pwm_dev_desc = {
        .flags = LPSS_SAVE_CTX,
+       .prv_offset = 0x800,
        .setup = byt_pwm_setup,
 };
 
 static const struct lpss_device_desc bsw_pwm_dev_desc = {
        .flags = LPSS_SAVE_CTX | LPSS_NO_D3_DELAY,
+       .prv_offset = 0x800,
        .setup = bsw_pwm_setup,
 };