[PATCH v3] i2c: designware: Add support for AMD i2c controller

[PATCH v3] i2c: designware: Add support for AMD i2c controller

[Carl Peng]

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-core.h    |  1 +
 drivers/i2c/busses/i2c-designware-platdrv.c | 46 +++++++++++++++++++++++++----
 2 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index d66b6cb..c67d4ac 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -105,6 +105,7 @@ struct dw_i2c_dev {
 	u16			ss_lcnt;
 	u16			fs_hcnt;
 	u16			fs_lcnt;
+	struct	dw_i2c_pdata	*pdata;
 };
 
 #define ACCESS_SWAP		0x00000001
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index bc87733..8a96e69 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -43,15 +43,31 @@
 #include <linux/acpi.h>
 #include "i2c-designware-core.h"
 
+#define AMD_CLK_KHZ		(133 * 1000)
+
+struct dw_i2c_pdata {
+	u32 clk_rate_khz;
+};
+
 static struct i2c_algorithm i2c_dw_algo = {
 	.master_xfer	= i2c_dw_xfer,
 	.functionality	= i2c_dw_func,
 };
+
+static struct dw_i2c_pdata amd_i2c_config = {
+	.clk_rate_khz = AMD_CLK_KHZ,
+};
+
 static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
 {
 	return clk_get_rate(dev->clk)/1000;
 }
 
+static u32 amd_i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
+{
+	return dev->pdata->clk_rate_khz;
+}
+
 #ifdef CONFIG_ACPI
 static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
 			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
@@ -107,7 +123,8 @@ 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
@@ -116,6 +133,17 @@ static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
 	return -ENODEV;
 }
 #endif
+struct dw_i2c_pdata *get_amd_i2c_driver_data(
+					struct platform_device *pdev)
+{
+	const struct acpi_device_id *id;
+
+	id = acpi_match_device(dw_i2c_acpi_match, &pdev->dev);
+	if (id)
+		return (struct dw_i2c_pdata *)id->driver_data;
+
+	return NULL;
+}
 
 static int dw_i2c_probe(struct platform_device *pdev)
 {
@@ -145,12 +173,18 @@ 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;
+	dev->pdata = get_amd_i2c_driver_data(pdev);
+
+	if (!dev->pdata) {
+		dev->clk = devm_clk_get(&pdev->dev, NULL);
+		dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
+
+		if (IS_ERR(dev->clk))
+			return PTR_ERR(dev->clk);
+		clk_prepare_enable(dev->clk);
+	} else
+		dev->get_clk_rate_khz = amd_i2c_dw_get_clk_rate_khz;
 
-	if (IS_ERR(dev->clk))
-		return PTR_ERR(dev->clk);
-	clk_prepare_enable(dev->clk);
 
 	if (pdev->dev.of_node) {
 		u32 ht = 0;
-- 
1.9.1

Re: [PATCH v3] i2c: designware: Add support for AMD i2c controller

[Mika Westerberg]

On Tue, Sep 16, 2014 at 02:20:58PM +0800, Carl Peng wrote:
> 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.

This is looking better now. I still have few comments, though.

> 
> Signed-off-by: Carl Peng <carlpeng008-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> Cc: Huang Rui <ray.huang-5C7GfCeVMHo@public.gmane.org>
> ---
>  drivers/i2c/busses/i2c-designware-core.h    |  1 +
>  drivers/i2c/busses/i2c-designware-platdrv.c | 46 +++++++++++++++++++++++++----
>  2 files changed, 41 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index d66b6cb..c67d4ac 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -105,6 +105,7 @@ struct dw_i2c_dev {
>  	u16			ss_lcnt;
>  	u16			fs_hcnt;
>  	u16			fs_lcnt;
> +	struct	dw_i2c_pdata	*pdata;

You don't need this.

>  };
>  
>  #define ACCESS_SWAP		0x00000001
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index bc87733..8a96e69 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -43,15 +43,31 @@
>  #include <linux/acpi.h>
>  #include "i2c-designware-core.h"
>  
> +#define AMD_CLK_KHZ		(133 * 1000)

Do you really need define for this?

> +
> +struct dw_i2c_pdata {
> +	u32 clk_rate_khz;
> +};

Call it dw_i2c_config instead.

> +
>  static struct i2c_algorithm i2c_dw_algo = {
>  	.master_xfer	= i2c_dw_xfer,
>  	.functionality	= i2c_dw_func,
>  };
> +
> +static struct dw_i2c_pdata amd_i2c_config = {
> +	.clk_rate_khz = AMD_CLK_KHZ,
> +};
> +
>  static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
>  {
>  	return clk_get_rate(dev->clk)/1000;

How about doing this instead?

	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;

And then just implement i2c_dw_get_config() that understands to look
clk_rate from acpi_device_id.

>  }
>  
> +static u32 amd_i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)

Please don't call it amd_xxx because if now some other vendor decides
that their version of dw ip runs at 120MHz we would need to rename this.

> +{
> +	return dev->pdata->clk_rate_khz;
> +}
> +