media: atomisp: properly parse CLK PMIC on newer devices

Newer devices don't place the PMIC CLK line inside an EFI
var. Instead, those are found at the _PR0 table.

Add a parser for it, using info stored via the DSDT table.

Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
index 3e8ec3ed5d2419b22b4fcc8bb96a073eaaf37241..39e585faf0c5e62cf50f00ef38f66abc7ee9c9f9 100644 (file)
--- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
@@ -444,6 +444,61 @@ static int gmin_i2c_write(struct device *dev, u16 i2c_addr, u8 reg,
        return ret;
 }
 
+static int atomisp_get_acpi_power(struct device *dev, acpi_handle handle)
+{
+       char name[5];
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       struct acpi_buffer b_name = { sizeof(name), name };
+       union acpi_object *package, *element;
+       acpi_handle rhandle;
+       acpi_status status;
+       int clock_num = -1;
+       int i;
+
+       status = acpi_evaluate_object(handle, "_PR0", NULL, &buffer);
+       if (!ACPI_SUCCESS(status))
+               return -1;
+
+       package = buffer.pointer;
+
+       if (!buffer.length || !package
+           || package->type != ACPI_TYPE_PACKAGE
+           || !package->package.count)
+               goto fail;
+
+       for (i = 0; i < package->package.count; i++) {
+               element = &package->package.elements[i];
+
+               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
+                       continue;
+
+               rhandle = element->reference.handle;
+               if (!rhandle)
+                       goto fail;
+
+               acpi_get_name(rhandle, ACPI_SINGLE_NAME, &b_name);
+
+               dev_dbg(dev, "Found PM resource '%s'\n", name);
+               if (strlen(name) == 4 && !strncmp(name, "CLK", 3)) {
+                       if (name[3] >= '0' && name[3] <= '4')
+                               clock_num = name[3] - '0';
+#if 0
+                       /*
+                        * We could abort here, but let's parse all resources,
+                        * as this is helpful for debugging purposes
+                        */
+                       if (clock_num >= 0)
+                               break;
+#endif
+               }
+       }
+
+fail:
+       ACPI_FREE(buffer.pointer);
+
+       return clock_num;
+}
+
 static struct gmin_subdev *gmin_subdev_add(struct v4l2_subdev *subdev)
 {
        struct i2c_client *power = NULL, *client = v4l2_get_subdevdata(subdev);
@@ -451,7 +506,7 @@ static struct gmin_subdev *gmin_subdev_add(struct v4l2_subdev *subdev)
        struct gmin_subdev *gs;
        acpi_handle handle;
        struct device *dev;
-       int i, ret, clock_num;
+       int i, ret, clock_num = -1;
 
        if (!client)
                return NULL;
@@ -557,7 +612,14 @@ static struct gmin_subdev *gmin_subdev_add(struct v4l2_subdev *subdev)
         * is a power resource already, falling back to the EFI vars detection
         * otherwise.
         */
-       clock_num = gmin_get_var_int(dev, false, "CamClk", -1);
+
+       /* Try first to use ACPI to get the clock resource */
+       if (acpi_device_power_manageable(adev))
+               clock_num = atomisp_get_acpi_power(dev, handle);
+
+       /* Fall-back use EFI and/or DMI match */
+       if (clock_num < 0)
+               clock_num = gmin_get_var_int(dev, false, "CamClk", 0);
 
        if (clock_num < 0 || clock_num > MAX_CLK_COUNT) {
                dev_err(dev, "Invalid clock number\n");