i2c: designware: Disable pm for PMIC i2c-bus even if there is no _SEM method

Cherrytrail devices use the dw i2c-bus with uid 7 to access their PMIC.
Even if the i2c-bus to the PMIC is not shared with the SoC's P-Unit
and i2c-designware-baytrail.c thus does not set the pm_disabled flag,
we still need to disable pm so that ACPI PMIC opregions can access the
PMIC during late-suspend and early-resume.

This fixes errors like these blocking suspend:

  i2c_designware 808622C1:06: timeout waiting for bus ready
  ACPI Exception: AE_ERROR, Returned by Handler for [UserDefinedRegion]
  acpi 80860F14:02: Failed to change power state to D3hot
  PM: late suspend of devices failed

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 0b6f6dc..a597ba3 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -95,7 +95,10 @@ static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
 static int dw_i2c_acpi_configure(struct platform_device *pdev)
 {
        struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+       acpi_handle handle = ACPI_HANDLE(&pdev->dev);
        const struct acpi_device_id *id;
+       struct acpi_device *adev;
+       const char *uid;
 
        dev->adapter.nr = -1;
        dev->tx_fifo_depth = 32;
@@ -115,6 +118,18 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev)
        if (id && id->driver_data)
                dev->flags |= (u32)id->driver_data;
 
+       if (acpi_bus_get_device(handle, &adev))
+               return -ENODEV;
+
+       /*
+        * Cherrytrail I2C7 gets used for the PMIC which gets accessed
+        * through ACPI opregions during late suspend / early resume
+        * disable pm for it.
+        */
+       uid = adev->pnp.unique_id;
+       if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
+               dev->pm_disabled = true;
+
        return 0;
 }