[PATCH v4] i2c: designware: Add support for AMD i2c controller

[Carl Peng <carlpeng008-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

AMD i2c bus controller is ACPI device, its ACPI ID
is "AMD0010". This patch is used to add support for
AMD i2c bus controller in the Designware platform
driver.

Signed-off-by: Carl Peng <carlpeng008-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Huang Rui <ray.huang-5C7GfCeVMHo@public.gmane.org>
---
 drivers/i2c/busses/i2c-designware-platdrv.c | 53 +++++++++++++++++++++++------
 1 file changed, 43 insertions(+), 10 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index bc87733..20015e6 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -43,14 +43,18 @@
 #include <linux/acpi.h>
 #include "i2c-designware-core.h"
 
+struct dw_i2c_config {
+	u32 clk_rate_khz;
+};
+
 static struct i2c_algorithm i2c_dw_algo = {
 	.master_xfer	= i2c_dw_xfer,
 	.functionality	= i2c_dw_func,
 };
-static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
-{
-	return clk_get_rate(dev->clk)/1000;
-}
+
+static struct dw_i2c_config amd_i2c_config = {
+	.clk_rate_khz = 133 * 1000,
+};
 
 #ifdef CONFIG_ACPI
 static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
@@ -107,7 +111,8 @@ static const struct acpi_device_id dw_i2c_acpi_match[] = {
 	{ "INT3433", 0 },
 	{ "80860F41", 0 },
 	{ "808622C1", 0 },
-	{ }
+	{ "AMD0010", (unsigned long)&amd_i2c_config },
+	{},
 };
 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
 #else
@@ -117,12 +122,35 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 }
 #endif
 
+static const struct dw_i2c_config *i2c_dw_get_config(
+					struct dw_i2c_dev *dev)
+{
+	const struct acpi_device_id *id;
+
+	id = acpi_match_device(dw_i2c_acpi_match, dev->dev);
+	if (id)
+		return (const struct dw_i2c_config *)id->driver_data;
+
+	return NULL;
+}
+
+static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
+{
+	const struct dw_i2c_config *conf = i2c_dw_get_config(dev);
+
+	if (conf)
+		return conf->clk_rate_khz;
+
+	return clk_get_rate(dev->clk)/1000;
+}
+
 static int dw_i2c_probe(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev;
 	struct i2c_adapter *adap;
 	struct resource *mem;
 	int irq, r;
+	const struct dw_i2c_config *conf;
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
@@ -145,12 +173,17 @@ static int dw_i2c_probe(struct platform_device *pdev)
 	dev->irq = irq;
 	platform_set_drvdata(pdev, dev);
 
-	dev->clk = devm_clk_get(&pdev->dev, NULL);
-	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
+	conf = i2c_dw_get_config(dev);
+
+	if (!conf) {
+		dev->clk = devm_clk_get(&pdev->dev, NULL);
 
-	if (IS_ERR(dev->clk))
-		return PTR_ERR(dev->clk);
-	clk_prepare_enable(dev->clk);
+		if (IS_ERR(dev->clk))
+			return PTR_ERR(dev->clk);
+		clk_prepare_enable(dev->clk);
+	}
+
+	dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
 
 	if (pdev->dev.of_node) {
 		u32 ht = 0;
-- 
1.9.1