ACPI: APD: Add AMD misc clock handler support

AMD SoC exposes clock for general purpose use. The clock registration
is done in clk-st driver. The MMIO mapping are passed on to the
clock driver for accessing the registers.
The misc clock handler will create MMIO mappings to access the
clock registers and enable the clock driver to expose the clock
for use of drivers which will connect to it.

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_apd.c

@@ -11,6 +11,7 @@
  */
 
 #include <linux/clk-provider.h>
+#include <linux/platform_data/clk-st.h>
 #include <linux/platform_device.h>
 #include <linux/pm_domain.h>
 #include <linux/clkdev.h>
@@ -72,6 +73,47 @@ static int acpi_apd_setup(struct apd_private_data *pdata)
 }
 
 #ifdef CONFIG_X86_AMD_PLATFORM_DEVICE
+
+static int misc_check_res(struct acpi_resource *ares, void *data)
+{
+	struct resource res;
+
+	return !acpi_dev_resource_memory(ares, &res);
+}
+
+static int st_misc_setup(struct apd_private_data *pdata)
+{
+	struct acpi_device *adev = pdata->adev;
+	struct platform_device *clkdev;
+	struct st_clk_data *clk_data;
+	struct resource_entry *rentry;
+	struct list_head resource_list;
+	int ret;
+
+	clk_data = devm_kzalloc(&adev->dev, sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list, misc_check_res,
+				     NULL);
+	if (ret < 0)
+		return -ENOENT;
+
+	list_for_each_entry(rentry, &resource_list, node) {
+		clk_data->base = devm_ioremap(&adev->dev, rentry->res->start,
+					      resource_size(rentry->res));
+		break;
+	}
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	clkdev = platform_device_register_data(&adev->dev, "clk-st",
+					       PLATFORM_DEVID_NONE, clk_data,
+					       sizeof(*clk_data));
+	return PTR_ERR_OR_ZERO(clkdev);
+}
+
 static const struct apd_device_desc cz_i2c_desc = {
 	.setup = acpi_apd_setup,
 	.fixed_clk_rate = 133000000,
@@ -94,6 +136,10 @@ static const struct apd_device_desc cz_uart_desc = {
 	.fixed_clk_rate = 48000000,
 	.properties = uart_properties,
 };
+
+static const struct apd_device_desc st_misc_desc = {
+	.setup = st_misc_setup,
+};
 #endif
 
 #ifdef CONFIG_ARM64
@@ -179,6 +225,7 @@ static const struct acpi_device_id acpi_apd_device_ids[] = {
 	{ "AMD0020", APD_ADDR(cz_uart_desc) },
 	{ "AMDI0020", APD_ADDR(cz_uart_desc) },
 	{ "AMD0030", },
+	{ "AMD0040", APD_ADDR(st_misc_desc)},
 #endif
 #ifdef CONFIG_ARM64
 	{ "APMC0D0F", APD_ADDR(xgene_i2c_desc) },