[PATCH 0/3 v2] Updates for exynos4210 and DT-based systems

[PATCH 0/3 v2] Updates for exynos4210 and DT-based systems

[Karol Lewandowski]

Changes since v1:
 - Move unrelated code fragment to separate patch (of_match_ptr())
 - Move device-type handling to separate function and rework its
   internals a bit

This patchset reworks i2c-s3c2410 driver a bit to better handle
device tree-enabled platforms and adds two quirks required by
exynos4210-specific I2C controller used by s5p-hdmi driver.

This patchset is based on "i2c-bjdooks/for-34/i2c/i2c-samsung" branch
taken from:

  git://git.fluff.org/bjdooks/linux.git

Karol Lewandowski (3):
  i2c-s3c2410: Drop unused define
  i2c-s3c2410: Rework device type handling
  i2c-s3c2410: Add HDMIPHY quirk for S3C2440

 .../devicetree/bindings/i2c/samsung-i2c.txt        |   10 ++-
 drivers/i2c/busses/i2c-s3c2410.c                   |   93 +++++++++++++++-----
 2 files changed, 77 insertions(+), 26 deletions(-)

-- 
1.7.9

[PATCH 1/3] i2c-s3c2410: Drop unused define

[Karol Lewandowski]

Use standard of_match_ptr() to avoid defining variable unused
in non device tree builds.

Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/i2c/busses/i2c-s3c2410.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 737f721..85e3664 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -1128,8 +1128,6 @@ static const struct of_device_id s3c24xx_i2c_match[] = {
 	{},
 };
 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
-#else
-#define s3c24xx_i2c_match NULL
 #endif
 
 static struct platform_driver s3c24xx_i2c_driver = {
@@ -1140,7 +1138,7 @@ static struct platform_driver s3c24xx_i2c_driver = {
 		.owner	= THIS_MODULE,
 		.name	= "s3c-i2c",
 		.pm	= S3C24XX_DEV_PM_OPS,
-		.of_match_table = s3c24xx_i2c_match,
+		.of_match_table = of_match_ptr(s3c24xx_i2c_match),
 	},
 };
 
-- 
1.7.9

[PATCH 2/3] i2c-s3c2410: Rework device type handling

[Karol Lewandowski]

Reorganize driver a bit to better handle device tree-based systems:

 - move machine type to driver's private structure instead of
   quering platform device variants in runtime

 - replace s3c24xx_i2c_type enum with plain unsigned int that can
   hold not only device type but also hw revision-specific quirks

Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/i2c/busses/i2c-s3c2410.c |   53 +++++++++++++++++++++++---------------
 1 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 85e3664..f84d26f 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -44,8 +44,16 @@
 #include <plat/regs-iic.h>
 #include <plat/iic.h>
 
-/* i2c controller state */
+#ifdef CONFIG_OF
+static const struct of_device_id s3c24xx_i2c_match[];
+#endif
+
+/* reserve lower 8 bits for device type, use remaining space for hw quirks */
+#define TYPE_BITS		0x000000ff
+#define TYPE_S3C2410		0x00000001
+#define TYPE_S3C2440		0x00000002
 
+/* i2c controller state */
 enum s3c24xx_i2c_state {
 	STATE_IDLE,
 	STATE_START,
@@ -54,14 +62,10 @@ enum s3c24xx_i2c_state {
 	STATE_STOP
 };
 
-enum s3c24xx_i2c_type {
-	TYPE_S3C2410,
-	TYPE_S3C2440,
-};
-
 struct s3c24xx_i2c {
 	spinlock_t		lock;
 	wait_queue_head_t	wait;
+	unsigned int            type;
 	unsigned int		suspended:1;
 
 	struct i2c_msg		*msg;
@@ -88,26 +92,32 @@ struct s3c24xx_i2c {
 #endif
 };
 
-/* default platform data removed, dev should always carry data. */
-
-/* s3c24xx_i2c_is2440()
+/* s3c24xx_i2c_is_type()
  *
- * return true is this is an s3c2440
+ * return true if this controller is of specified type
 */
 
-static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
+static inline int s3c24xx_i2c_is_type(struct s3c24xx_i2c *i2c, unsigned int type)
 {
-	struct platform_device *pdev = to_platform_device(i2c->dev);
-	enum s3c24xx_i2c_type type;
+	return (i2c->type & TYPE_BITS) == type;
+}
+
+/* s3c24xx_get_device_type
+ *
+ * Get controller type either from device tree or platform device variant.
+*/
 
+static inline unsigned int s3c24xx_get_device_type(struct platform_device *pdev)
+{
 #ifdef CONFIG_OF
-	if (i2c->dev->of_node)
-		return of_device_is_compatible(i2c->dev->of_node,
-				"samsung,s3c2440-i2c");
+	if (pdev->dev.of_node) {
+		const struct of_device_id *match;
+		match = of_match_node(&s3c24xx_i2c_match[0], pdev->dev.of_node);
+		return (unsigned int)match->data;
+	}
 #endif
 
-	type = platform_get_device_id(pdev)->driver_data;
-	return type == TYPE_S3C2440;
+	return platform_get_device_id(pdev)->driver_data;
 }
 
 /* s3c24xx_i2c_master_complete
@@ -676,7 +686,7 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 
 	writel(iiccon, i2c->regs + S3C2410_IICCON);
 
-	if (s3c24xx_i2c_is2440(i2c)) {
+	if (s3c24xx_i2c_is_type(i2c, TYPE_S3C2440)) {
 		unsigned long sda_delay;
 
 		if (pdata->sda_delay) {
@@ -906,6 +916,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		goto err_noclk;
 	}
 
+	i2c->type = s3c24xx_get_device_type(pdev);
 	if (pdata)
 		memcpy(i2c->pdata, pdata, sizeof(*pdata));
 	else
@@ -1123,8 +1134,8 @@ MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 
 #ifdef CONFIG_OF
 static const struct of_device_id s3c24xx_i2c_match[] = {
-	{ .compatible = "samsung,s3c2410-i2c" },
-	{ .compatible = "samsung,s3c2440-i2c" },
+	{ .compatible = "samsung,s3c2410-i2c", .data = (void *)TYPE_S3C2410 },
+	{ .compatible = "samsung,s3c2440-i2c", .data = (void *)TYPE_S3C2440 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
-- 
1.7.9

[PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
and other I2C controllers on Exynos4.  These differences are:
- no GPIOs, HDMIPHY is inside the SoC and the controller is connected
  internally
- due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
  transfer fails to finish. The controller hangs after sending the last byte,
  the workaround for this bug is resetting the controller after each transfer

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 .../devicetree/bindings/i2c/samsung-i2c.txt        |   10 ++++-
 drivers/i2c/busses/i2c-s3c2410.c                   |   36 ++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
index 38832c7..ac0917c 100644
--- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
@@ -10,14 +10,20 @@ Required properties:
     region.
   - interrupts: interrupt number to the cpu.
   - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
-  - gpios: The order of the gpios should be the following: <SDA, SCL>.
-    The gpio specifier depends on the gpio controller.
 
 Optional properties:
+  - gpios: The order of the gpios should be the following: <SDA, SCL>.
+    The gpio specifier depends on the gpio controller. Required in all cases
+    except when "samsung,i2c-no-gpio" is also specified.
+  - samsung,i2c-no-gpio: input/output lines of the controller are
+    permanently wired to the respective client, there are no gpio
+    lines that need to be configured to enable this controller
   - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
     specified, default value is 0.
   - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
     specified, the default value in Hz is 100000.
+  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block on S3C2440 -
+    reduce timeout and reset controller when doing transefers
 
 Example:
 
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index f84d26f..23bf7fa 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -52,6 +52,8 @@ static const struct of_device_id s3c24xx_i2c_match[];
 #define TYPE_BITS		0x000000ff
 #define TYPE_S3C2410		0x00000001
 #define TYPE_S3C2440		0x00000002
+#define FLAG_HDMIPHY		0x00000100
+#define FLAG_NO_GPIO		0x00000200
 
 /* i2c controller state */
 enum s3c24xx_i2c_state {
@@ -481,6 +483,13 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 	unsigned long iicstat;
 	int timeout = 400;
 
+	/* the timeout for HDMIPHY is reduced to 10 ms because
+	 * the hangup is expected to happen, so waiting 400 ms
+	 * causes only unnecessary system hangup
+	 */
+	if (i2c->type & FLAG_HDMIPHY)
+		timeout = 10;
+
 	while (timeout-- > 0) {
 		iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 
@@ -490,6 +499,15 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 		msleep(1);
 	}
 
+	/* hang-up of bus dedicated for HDMIPHY occurred, resetting */
+	if (i2c->type & FLAG_HDMIPHY) {
+		writel(0, i2c->regs + S3C2410_IICCON);
+		writel(0, i2c->regs + S3C2410_IICSTAT);
+		writel(0, i2c->regs + S3C2410_IICDS);
+
+		return 0;
+	}
+
 	return -ETIMEDOUT;
 }
 
@@ -771,6 +789,9 @@ static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 {
 	int idx, gpio, ret;
 
+	if (i2c->type & FLAG_NO_GPIO)
+		return 0;
+
 	for (idx = 0; idx < 2; idx++) {
 		gpio = of_get_gpio(i2c->dev->of_node, idx);
 		if (!gpio_is_valid(gpio)) {
@@ -795,6 +816,10 @@ free_gpio:
 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 {
 	unsigned int idx;
+
+	if (i2c->type & FLAG_NO_GPIO)
+		return;
+
 	for (idx = 0; idx < 2; idx++)
 		gpio_free(i2c->gpios[idx]);
 }
@@ -871,6 +896,14 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 		return;
 
 	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
+
+	if (s3c24xx_i2c_is_type(i2c, TYPE_S3C2440) &&
+	    of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
+		i2c->type |= FLAG_HDMIPHY;
+
+	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
+		i2c->type |= FLAG_NO_GPIO;
+
 	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 	of_property_read_u32(np, "samsung,i2c-max-bus-freq",
@@ -1128,6 +1161,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 	}, {
 		.name		= "s3c2440-i2c",
 		.driver_data	= TYPE_S3C2440,
+	}, {
+		.name		= "s3c2440-hdmiphy-i2c",
+		.driver_data	= TYPE_S3C2440 | FLAG_HDMIPHY | FLAG_NO_GPIO,
 	}, { },
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
-- 
1.7.9

Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Tomasz Stanislawski]

Hi Karol,
Please refer to comments below,

Regards,
Tomasz Stanislawski

On 03/13/2012 05:54 PM, Karol Lewandowski wrote:
> This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
> Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
> and other I2C controllers on Exynos4.  These differences are:
> - no GPIOs, HDMIPHY is inside the SoC and the controller is connected
>   internally
> - due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
>   transfer fails to finish. The controller hangs after sending the last byte,
>   the workaround for this bug is resetting the controller after each transfer
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
> Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  .../devicetree/bindings/i2c/samsung-i2c.txt        |   10 ++++-
>  drivers/i2c/busses/i2c-s3c2410.c                   |   36 ++++++++++++++++++++
>  2 files changed, 44 insertions(+), 2 deletions(-)
> 
[snip]
> @@ -871,6 +896,14 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
>  		return;
>  
>  	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
> +
> +	if (s3c24xx_i2c_is_type(i2c, TYPE_S3C2440) &&

I think that type checking should be removed because hdmiphy quirk is something
orthogonal to the controller type.

> +	    of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
> +		i2c->type |= FLAG_HDMIPHY;
> +
> +	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
> +		i2c->type |= FLAG_NO_GPIO;
> +
>  	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
>  	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
>  	of_property_read_u32(np, "samsung,i2c-max-bus-freq",
> @@ -1128,6 +1161,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
>  	}, {
>  		.name		= "s3c2440-i2c",
>  		.driver_data	= TYPE_S3C2440,
> +	}, {
> +		.name		= "s3c2440-hdmiphy-i2c",
> +		.driver_data	= TYPE_S3C2440 | FLAG_HDMIPHY | FLAG_NO_GPIO,
>  	}, { },
>  };
>  MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);

Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

On 13.03.2012 18:27, Tomasz Stanislawski wrote:

> Hi Karol,
> Please refer to comments below,
> 
> Regards,
> Tomasz Stanislawski
> 
> On 03/13/2012 05:54 PM, Karol Lewandowski wrote:
>> This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
>> Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
>> and other I2C controllers on Exynos4.  These differences are:
>> - no GPIOs, HDMIPHY is inside the SoC and the controller is connected
>>   internally
>> - due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
>>   transfer fails to finish. The controller hangs after sending the last byte,
>>   the workaround for this bug is resetting the controller after each transfer
>>
>> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>> Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
>> Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
>> ---
>>  .../devicetree/bindings/i2c/samsung-i2c.txt        |   10 ++++-
>>  drivers/i2c/busses/i2c-s3c2410.c                   |   36 ++++++++++++++++++++
>>  2 files changed, 44 insertions(+), 2 deletions(-)
>>
> [snip]
>> @@ -871,6 +896,14 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
>>  		return;
>>  
>>  	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
>> +
>> +	if (s3c24xx_i2c_is_type(i2c, TYPE_S3C2440) &&
> 
> I think that type checking should be removed because hdmiphy quirk is something
> orthogonal to the controller type.


Ok, I'll drop this test and resend patch in a minute.

Thanks!
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

[PATCH] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
and other I2C controllers on Exynos4.  These differences are:
- no GPIOs, HDMIPHY is inside the SoC and the controller is connected
  internally
- due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
  transfer fails to finish. The controller hangs after sending the last byte,
  the workaround for this bug is resetting the controller after each transfer

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 .../devicetree/bindings/i2c/samsung-i2c.txt        |   11 +++++-
 drivers/i2c/busses/i2c-s3c2410.c                   |   35 ++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
index 38832c7..c6670f9 100644
--- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
@@ -10,14 +10,21 @@ Required properties:
     region.
   - interrupts: interrupt number to the cpu.
   - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
-  - gpios: The order of the gpios should be the following: <SDA, SCL>.
-    The gpio specifier depends on the gpio controller.
 
 Optional properties:
+  - gpios: The order of the gpios should be the following: <SDA, SCL>.
+    The gpio specifier depends on the gpio controller. Required in all cases
+    except when "samsung,i2c-no-gpio" is also specified.
+  - samsung,i2c-no-gpio: input/output lines of the controller are
+    permanently wired to the respective client, there are no gpio
+    lines that need to be configured to enable this controller
   - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
     specified, default value is 0.
   - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
     specified, the default value in Hz is 100000.
+  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
+    Exynos4 platform - reduce timeout and reset controller after each
+    transfer
 
 Example:
 
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index f84d26f..fa5f8c4 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -52,6 +52,8 @@ static const struct of_device_id s3c24xx_i2c_match[];
 #define TYPE_BITS		0x000000ff
 #define TYPE_S3C2410		0x00000001
 #define TYPE_S3C2440		0x00000002
+#define FLAG_HDMIPHY		0x00000100
+#define FLAG_NO_GPIO		0x00000200
 
 /* i2c controller state */
 enum s3c24xx_i2c_state {
@@ -481,6 +483,13 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 	unsigned long iicstat;
 	int timeout = 400;
 
+	/* the timeout for HDMIPHY is reduced to 10 ms because
+	 * the hangup is expected to happen, so waiting 400 ms
+	 * causes only unnecessary system hangup
+	 */
+	if (i2c->type & FLAG_HDMIPHY)
+		timeout = 10;
+
 	while (timeout-- > 0) {
 		iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 
@@ -490,6 +499,15 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 		msleep(1);
 	}
 
+	/* hang-up of bus dedicated for HDMIPHY occurred, resetting */
+	if (i2c->type & FLAG_HDMIPHY) {
+		writel(0, i2c->regs + S3C2410_IICCON);
+		writel(0, i2c->regs + S3C2410_IICSTAT);
+		writel(0, i2c->regs + S3C2410_IICDS);
+
+		return 0;
+	}
+
 	return -ETIMEDOUT;
 }
 
@@ -771,6 +789,9 @@ static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 {
 	int idx, gpio, ret;
 
+	if (i2c->type & FLAG_NO_GPIO)
+		return 0;
+
 	for (idx = 0; idx < 2; idx++) {
 		gpio = of_get_gpio(i2c->dev->of_node, idx);
 		if (!gpio_is_valid(gpio)) {
@@ -795,6 +816,10 @@ free_gpio:
 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 {
 	unsigned int idx;
+
+	if (i2c->type & FLAG_NO_GPIO)
+		return;
+
 	for (idx = 0; idx < 2; idx++)
 		gpio_free(i2c->gpios[idx]);
 }
@@ -871,6 +896,13 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 		return;
 
 	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
+
+	if (of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
+		i2c->type |= FLAG_HDMIPHY;
+
+	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
+		i2c->type |= FLAG_NO_GPIO;
+
 	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 	of_property_read_u32(np, "samsung,i2c-max-bus-freq",
@@ -1128,6 +1160,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 	}, {
 		.name		= "s3c2440-i2c",
 		.driver_data	= TYPE_S3C2440,
+	}, {
+		.name		= "s3c2440-hdmiphy-i2c",
+		.driver_data	= TYPE_S3C2440 | FLAG_HDMIPHY | FLAG_NO_GPIO,
 	}, { },
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
-- 
1.7.9

Re: [PATCH 0/3 v2] Updates for exynos4210 and DT-based systems

[Kyungmin Park]

+CC another i2c subsystem maintainer, Wolfram Sang.

On 3/14/12, Karol Lewandowski <k.lewandowsk@samsung.com> wrote:
> Changes since v1:
>  - Move unrelated code fragment to separate patch (of_match_ptr())
>  - Move device-type handling to separate function and rework its
>    internals a bit
>
> This patchset reworks i2c-s3c2410 driver a bit to better handle
> device tree-enabled platforms and adds two quirks required by
> exynos4210-specific I2C controller used by s5p-hdmi driver.
>
> This patchset is based on "i2c-bjdooks/for-34/i2c/i2c-samsung" branch
> taken from:
>
>   git://git.fluff.org/bjdooks/linux.git
>
> Karol Lewandowski (3):
>   i2c-s3c2410: Drop unused define
>   i2c-s3c2410: Rework device type handling
>   i2c-s3c2410: Add HDMIPHY quirk for S3C2440
>
>  .../devicetree/bindings/i2c/samsung-i2c.txt        |   10 ++-
>  drivers/i2c/busses/i2c-s3c2410.c                   |   93
> +++++++++++++++-----
>  2 files changed, 77 insertions(+), 26 deletions(-)
>
> --
> 1.7.9
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc"
> in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Mark Brown]

On Tue, Mar 13, 2012 at 05:54:38PM +0100, Karol Lewandowski wrote:

>  - replace s3c24xx_i2c_type enum with plain unsigned int that can
>    hold not only device type but also hw revision-specific quirks

Would it not be clearer to just have explicit flags for the quirks (eg,
as a set of bitfield flags)?

Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Karol Lewandowski]

On 14.03.2012 18:29, Mark Brown wrote:

> On Tue, Mar 13, 2012 at 05:54:38PM +0100, Karol Lewandowski wrote:
> 
>>  - replace s3c24xx_i2c_type enum with plain unsigned int that can
>>    hold not only device type but also hw revision-specific quirks
> 
> Would it not be clearer to just have explicit flags for the quirks (eg,
> as a set of bitfield flags)?


That would work on runtime but we also need to initialize this
somehow.  The way it was done today on non-dt platforms is via platform
device variants, i.e. (taken from 3rd patch):

@@ -1128,6 +1161,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 	}, {
 		.name		= "s3c2440-i2c",
 		.driver_data	= TYPE_S3C2440,
+	}, {
+		.name		= "s3c2440-hdmiphy-i2c",
+		.driver_data	= TYPE_S3C2440 | FLAG_HDMIPHY | FLAG_NO_GPIO,

Ability to address above scenario was sole motivation for this change.
Without it one would need either need separate type (e.g. 
TYPE_S3C2440_HDMIPHY) or setting flags based just on device name.

Introducing separate type (TYPE_S3C2440_HDMIPHY) has been our original
attempt to solve this issue.  However, this required adding explicit
checks to driver code all over the place (if (type == S3C2400 ||
type == S3c2440_HDMIPHY).

Thus, I felt that sqeezing quirks into type is a bit cleaner approach.

Regards,
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 397 bytes --]

On Thu, Mar 15, 2012 at 11:04:56AM +0100, Karol Lewandowski wrote:

> Introducing separate type (TYPE_S3C2440_HDMIPHY) has been our original
> attempt to solve this issue.  However, this required adding explicit
> checks to driver code all over the place (if (type == S3C2400 ||
> type == S3c2440_HDMIPHY).

Another option is to change the type to be a pointer to a struct with
quirk flags in it.

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Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Karol Lewandowski]

On 15.03.2012 13:56, Mark Brown wrote:

> On Thu, Mar 15, 2012 at 11:04:56AM +0100, Karol Lewandowski wrote:
> 
>> Introducing separate type (TYPE_S3C2440_HDMIPHY) has been our original
>> attempt to solve this issue.  However, this required adding explicit
>> checks to driver code all over the place (if (type == S3C2400 ||
>> type == S3c2440_HDMIPHY).
> 
> Another option is to change the type to be a pointer to a struct with
> quirk flags in it.


Sure, that's possible.   However, I don't find it any simpler than
using  bitmasks.  Quite to contrary - I consider it redundant to
bring new structure into existence when simple uint does the trick
just fine (IMHO, of course).

If you consider code to be inherently less readable because of this
approach I'll rework it.  If it's not a such big deal for you I would
prefer to keep it as is.

Thanks!
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

Re: [PATCH 1/3] i2c-s3c2410: Drop unused define

[Grant Likely]

On Tue, 13 Mar 2012 17:54:37 +0100, Karol Lewandowski <k.lewandowsk@samsung.com> wrote:
> Use standard of_match_ptr() to avoid defining variable unused
> in non device tree builds.
> 
> Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

Acked-by: Grant Likely <grant.likely@secretlab.ca>

> ---
>  drivers/i2c/busses/i2c-s3c2410.c |    4 +---
>  1 files changed, 1 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
> index 737f721..85e3664 100644
> --- a/drivers/i2c/busses/i2c-s3c2410.c
> +++ b/drivers/i2c/busses/i2c-s3c2410.c
> @@ -1128,8 +1128,6 @@ static const struct of_device_id s3c24xx_i2c_match[] = {
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
> -#else
> -#define s3c24xx_i2c_match NULL
>  #endif
>  
>  static struct platform_driver s3c24xx_i2c_driver = {
> @@ -1140,7 +1138,7 @@ static struct platform_driver s3c24xx_i2c_driver = {
>  		.owner	= THIS_MODULE,
>  		.name	= "s3c-i2c",
>  		.pm	= S3C24XX_DEV_PM_OPS,
> -		.of_match_table = s3c24xx_i2c_match,
> +		.of_match_table = of_match_ptr(s3c24xx_i2c_match),
>  	},
>  };
>  
> -- 
> 1.7.9
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.

Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 567 bytes --]

On Thu, Mar 15, 2012 at 05:54:33PM +0100, Karol Lewandowski wrote:

> If you consider code to be inherently less readable because of this
> approach I'll rework it.  If it's not a such big deal for you I would
> prefer to keep it as is.

The thing that was causing me to think the code was funny was mainly the
fact that we're now combining both quirk based selection and chip type
based selection into the same bitmask.  If the chip types were quirks
it'd probably not have looked odd, and that might just be a case of
renaming them - I can't remember what they do.

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Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Karol Lewandowski]

On 19.03.2012 20:55, Mark Brown wrote:

> On Thu, Mar 15, 2012 at 05:54:33PM +0100, Karol Lewandowski wrote:
> 
>> If you consider code to be inherently less readable because of this
>> approach I'll rework it.  If it's not a such big deal for you I would
>> prefer to keep it as is.
> 
> The thing that was causing me to think the code was funny was mainly the
> fact that we're now combining both quirk based selection and chip type
> based selection into the same bitmask.  If the chip types were quirks
> it'd probably not have looked odd, and that might just be a case of
> renaming them - I can't remember what they do.


What do you think about following changes, then?

diff --git a/drivers/i2c/busses/i2c-s3c2410.c
b/drivers/i2c/busses/i2c-s3c2410.c
index fa5f8c4..18c9760 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -48,12 +48,9 @@
 static const struct of_device_id s3c24xx_i2c_match[];
 #endif

-/* reserve lower 8 bits for device type, use remaining space for hw
quirks */
-#define TYPE_BITS		0x000000ff
-#define TYPE_S3C2410		0x00000001
-#define TYPE_S3C2440		0x00000002
-#define FLAG_HDMIPHY		0x00000100
-#define FLAG_NO_GPIO		0x00000200
+#define QUIRK_S3C2440		(1 << 0)
+#define QUIRK_HDMIPHY		(1 << 1)
+#define QUIRK_NO_GPIO		(1 << 2)

 /* i2c controller state */
 enum s3c24xx_i2c_state {
@@ -67,7 +64,7 @@ enum s3c24xx_i2c_state {
 struct s3c24xx_i2c {
 	spinlock_t		lock;
 	wait_queue_head_t	wait;
-	unsigned int            type;
+	unsigned int            quirks;
 	unsigned int		suspended:1;

 	struct i2c_msg		*msg;
@@ -94,22 +91,12 @@ struct s3c24xx_i2c {
 #endif
 };

-/* s3c24xx_i2c_is_type()
- *
- * return true if this controller is of specified type
-*/
-
-static inline int s3c24xx_i2c_is_type(struct s3c24xx_i2c *i2c, unsigned
int type)
-{
-	return (i2c->type & TYPE_BITS) == type;
-}
-
-/* s3c24xx_get_device_type
+/* s3c24xx_get_device_quirks
  *
  * Get controller type either from device tree or platform device variant.
 */

-static inline unsigned int s3c24xx_get_device_type(struct
platform_device *pdev)
+static inline unsigned int s3c24xx_get_device_quirks(struct
platform_device *pdev)
 {
 #ifdef CONFIG_OF
         if (pdev->dev.of_node) {
@@ -487,7 +474,7 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c
*i2c)
 	 * the hangup is expected to happen, so waiting 400 ms
 	 * causes only unnecessary system hangup
 	 */
-	if (i2c->type & FLAG_HDMIPHY)
+	if (i2c->quirks & QUIRK_HDMIPHY)
 		timeout = 10;

 	while (timeout-- > 0) {
@@ -500,7 +487,7 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c
*i2c)
 	}

 	/* hang-up of bus dedicated for HDMIPHY occurred, resetting */
-	if (i2c->type & FLAG_HDMIPHY) {
+	if (i2c->quirks & QUIRK_HDMIPHY) {
 		writel(0, i2c->regs + S3C2410_IICCON);
 		writel(0, i2c->regs + S3C2410_IICSTAT);
 		writel(0, i2c->regs + S3C2410_IICDS);
@@ -704,7 +691,7 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c
*i2c, unsigned int *got)

 	writel(iiccon, i2c->regs + S3C2410_IICCON);

-	if (s3c24xx_i2c_is_type(i2c, TYPE_S3C2440)) {
+	if (i2c->quirks & QUIRK_S3C2440) {
 		unsigned long sda_delay;

 		if (pdata->sda_delay) {
@@ -789,7 +776,7 @@ static int s3c24xx_i2c_parse_dt_gpio(struct
s3c24xx_i2c *i2c)
 {
 	int idx, gpio, ret;

-	if (i2c->type & FLAG_NO_GPIO)
+	if (i2c->quirks & QUIRK_NO_GPIO)
 		return 0;

 	for (idx = 0; idx < 2; idx++) {
@@ -817,7 +804,7 @@ static void s3c24xx_i2c_dt_gpio_free(struct
s3c24xx_i2c *i2c)
 {
 	unsigned int idx;

-	if (i2c->type & FLAG_NO_GPIO)
+	if (i2c->quirks & QUIRK_NO_GPIO)
 		return;

 	for (idx = 0; idx < 2; idx++)
@@ -898,10 +885,10 @@ s3c24xx_i2c_parse_dt(struct device_node *np,
struct s3c24xx_i2c *i2c)
 	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */

 	if (of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
-		i2c->type |= FLAG_HDMIPHY;
+		i2c->quirks |= QUIRK_HDMIPHY;

 	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
-		i2c->type |= FLAG_NO_GPIO;
+		i2c->quirks |= QUIRK_NO_GPIO;

 	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
@@ -948,7 +935,7 @@ static int s3c24xx_i2c_probe(struct platform_device
*pdev)
 		goto err_noclk;
 	}

-	i2c->type = s3c24xx_get_device_type(pdev);
+	i2c->quirks = s3c24xx_get_device_quirks(pdev);
 	if (pdata)
 		memcpy(i2c->pdata, pdata, sizeof(*pdata));
 	else
@@ -1156,21 +1143,21 @@ static const struct dev_pm_ops
s3c24xx_i2c_dev_pm_ops = {
 static struct platform_device_id s3c24xx_driver_ids[] = {
 	{
 		.name		= "s3c2410-i2c",
-		.driver_data	= TYPE_S3C2410,
+		.driver_data	= 0,
 	}, {
 		.name		= "s3c2440-i2c",
-		.driver_data	= TYPE_S3C2440,
+		.driver_data	= QUIRK_S3C2440,
 	}, {
 		.name		= "s3c2440-hdmiphy-i2c",
-		.driver_data	= TYPE_S3C2440 | FLAG_HDMIPHY | FLAG_NO_GPIO,
+		.driver_data	= QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
 	}, { },
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);

 #ifdef CONFIG_OF
 static const struct of_device_id s3c24xx_i2c_match[] = {
-	{ .compatible = "samsung,s3c2410-i2c", .data = (void *)TYPE_S3C2410 },
-	{ .compatible = "samsung,s3c2440-i2c", .data = (void *)TYPE_S3C2440 },
+	{ .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
+	{ .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);


Regards,
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 143 bytes --]

On Wed, Mar 21, 2012 at 11:33:58AM +0100, Karol Lewandowski wrote:

> What do you think about following changes, then?

That looks reasonable.

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Re: [PATCH 2/3] i2c-s3c2410: Rework device type handling

[Karol Lewandowski]

On 21.03.2012 12:50, Mark Brown wrote:

> On Wed, Mar 21, 2012 at 11:33:58AM +0100, Karol Lewandowski wrote:
> 
>> What do you think about following changes, then?
> 
> That looks reasonable.


Thanks. I'll incorporate this change and post whole patchset again.

Regards,
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

[PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
and other I2C controllers on Exynos4.  These differences are:
- no GPIOs, HDMIPHY is inside the SoC and the controller is connected
  internally
- due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
  transfer fails to finish. The controller hangs after sending the last byte,
  the workaround for this bug is resetting the controller after each transfer

Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 .../devicetree/bindings/i2c/samsung-i2c.txt        |   11 +++++-
 drivers/i2c/busses/i2c-s3c2410.c                   |   35 ++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
index 38832c7..c6670f9 100644
--- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
@@ -10,14 +10,21 @@ Required properties:
     region.
   - interrupts: interrupt number to the cpu.
   - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
-  - gpios: The order of the gpios should be the following: <SDA, SCL>.
-    The gpio specifier depends on the gpio controller.
 
 Optional properties:
+  - gpios: The order of the gpios should be the following: <SDA, SCL>.
+    The gpio specifier depends on the gpio controller. Required in all cases
+    except when "samsung,i2c-no-gpio" is also specified.
+  - samsung,i2c-no-gpio: input/output lines of the controller are
+    permanently wired to the respective client, there are no gpio
+    lines that need to be configured to enable this controller
   - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
     specified, default value is 0.
   - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
     specified, the default value in Hz is 100000.
+  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
+    Exynos4 platform - reduce timeout and reset controller after each
+    transfer
 
 Example:
 
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index f7b6a14..e50f523 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -50,6 +50,8 @@ static const struct of_device_id s3c24xx_i2c_match[];
 
 /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
 #define QUIRK_S3C2440		(1 << 0)
+#define QUIRK_HDMIPHY		(1 << 1)
+#define QUIRK_NO_GPIO		(1 << 2)
 
 /* i2c controller state */
 enum s3c24xx_i2c_state {
@@ -469,6 +471,13 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 	unsigned long iicstat;
 	int timeout = 400;
 
+	/* the timeout for HDMIPHY is reduced to 10 ms because
+	 * the hangup is expected to happen, so waiting 400 ms
+	 * causes only unnecessary system hangup
+	 */
+	if (i2c->quirks & QUIRK_HDMIPHY)
+		timeout = 10;
+
 	while (timeout-- > 0) {
 		iicstat = readl(i2c->regs + S3C2410_IICSTAT);
 
@@ -478,6 +487,15 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
 		msleep(1);
 	}
 
+	/* hang-up of bus dedicated for HDMIPHY occurred, resetting */
+	if (i2c->quirks & QUIRK_HDMIPHY) {
+		writel(0, i2c->regs + S3C2410_IICCON);
+		writel(0, i2c->regs + S3C2410_IICSTAT);
+		writel(0, i2c->regs + S3C2410_IICDS);
+
+		return 0;
+	}
+
 	return -ETIMEDOUT;
 }
 
@@ -759,6 +777,9 @@ static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
 {
 	int idx, gpio, ret;
 
+	if (i2c->quirks & QUIRK_NO_GPIO)
+		return 0;
+
 	for (idx = 0; idx < 2; idx++) {
 		gpio = of_get_gpio(i2c->dev->of_node, idx);
 		if (!gpio_is_valid(gpio)) {
@@ -783,6 +804,10 @@ free_gpio:
 static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
 {
 	unsigned int idx;
+
+	if (i2c->quirks & QUIRK_NO_GPIO)
+		return;
+
 	for (idx = 0; idx < 2; idx++)
 		gpio_free(i2c->gpios[idx]);
 }
@@ -859,6 +884,13 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 		return;
 
 	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
+
+	if (of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
+		i2c->quirks |= QUIRK_HDMIPHY;
+
+	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
+		i2c->quirks |= QUIRK_NO_GPIO;
+
 	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
 	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
 	of_property_read_u32(np, "samsung,i2c-max-bus-freq",
@@ -1116,6 +1148,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 	}, {
 		.name		= "s3c2440-i2c",
 		.driver_data	= QUIRK_S3C2440,
+	}, {
+		.name		= "s3c2440-hdmiphy-i2c",
+		.driver_data	= QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
 	}, { },
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
-- 
1.7.9

Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 5848 bytes --]

Hi,

On Wed, Mar 21, 2012 at 08:11:53PM +0100, Karol Lewandowski wrote:
> This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
> Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
> and other I2C controllers on Exynos4.  These differences are:
> - no GPIOs, HDMIPHY is inside the SoC and the controller is connected
>   internally
> - due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
>   transfer fails to finish. The controller hangs after sending the last byte,
>   the workaround for this bug is resetting the controller after each transfer
> 
> Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
> Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  .../devicetree/bindings/i2c/samsung-i2c.txt        |   11 +++++-
>  drivers/i2c/busses/i2c-s3c2410.c                   |   35 ++++++++++++++++++++
>  2 files changed, 44 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> index 38832c7..c6670f9 100644
> --- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> +++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> @@ -10,14 +10,21 @@ Required properties:
>      region.
>    - interrupts: interrupt number to the cpu.
>    - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
> -  - gpios: The order of the gpios should be the following: <SDA, SCL>.
> -    The gpio specifier depends on the gpio controller.
>  
>  Optional properties:
> +  - gpios: The order of the gpios should be the following: <SDA, SCL>.
> +    The gpio specifier depends on the gpio controller. Required in all cases
> +    except when "samsung,i2c-no-gpio" is also specified.
> +  - samsung,i2c-no-gpio: input/output lines of the controller are
> +    permanently wired to the respective client, there are no gpio
> +    lines that need to be configured to enable this controller

Can't we just skip this property...


>    - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
>      specified, default value is 0.
>    - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
>      specified, the default value in Hz is 100000.
> +  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
> +    Exynos4 platform - reduce timeout and reset controller after each
> +    transfer

... and this one, if we declare a new compatible-entry for exynos4?

>  
>  Example:
>  
> diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
> index f7b6a14..e50f523 100644
> --- a/drivers/i2c/busses/i2c-s3c2410.c
> +++ b/drivers/i2c/busses/i2c-s3c2410.c
> @@ -50,6 +50,8 @@ static const struct of_device_id s3c24xx_i2c_match[];
>  
>  /* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
>  #define QUIRK_S3C2440		(1 << 0)
> +#define QUIRK_HDMIPHY		(1 << 1)
> +#define QUIRK_NO_GPIO		(1 << 2)
>  
>  /* i2c controller state */
>  enum s3c24xx_i2c_state {
> @@ -469,6 +471,13 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
>  	unsigned long iicstat;
>  	int timeout = 400;
>  
> +	/* the timeout for HDMIPHY is reduced to 10 ms because
> +	 * the hangup is expected to happen, so waiting 400 ms
> +	 * causes only unnecessary system hangup
> +	 */
> +	if (i2c->quirks & QUIRK_HDMIPHY)
> +		timeout = 10;
> +
>  	while (timeout-- > 0) {
>  		iicstat = readl(i2c->regs + S3C2410_IICSTAT);
>  
> @@ -478,6 +487,15 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
>  		msleep(1);
>  	}
>  
> +	/* hang-up of bus dedicated for HDMIPHY occurred, resetting */
> +	if (i2c->quirks & QUIRK_HDMIPHY) {
> +		writel(0, i2c->regs + S3C2410_IICCON);
> +		writel(0, i2c->regs + S3C2410_IICSTAT);
> +		writel(0, i2c->regs + S3C2410_IICDS);
> +
> +		return 0;
> +	}
> +
>  	return -ETIMEDOUT;
>  }
>  
> @@ -759,6 +777,9 @@ static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
>  {
>  	int idx, gpio, ret;
>  
> +	if (i2c->quirks & QUIRK_NO_GPIO)
> +		return 0;
> +
>  	for (idx = 0; idx < 2; idx++) {
>  		gpio = of_get_gpio(i2c->dev->of_node, idx);
>  		if (!gpio_is_valid(gpio)) {
> @@ -783,6 +804,10 @@ free_gpio:
>  static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
>  {
>  	unsigned int idx;
> +
> +	if (i2c->quirks & QUIRK_NO_GPIO)
> +		return;
> +
>  	for (idx = 0; idx < 2; idx++)
>  		gpio_free(i2c->gpios[idx]);
>  }
> @@ -859,6 +884,13 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
>  		return;
>  
>  	pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
> +
> +	if (of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
> +		i2c->quirks |= QUIRK_HDMIPHY;
> +
> +	if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
> +		i2c->quirks |= QUIRK_NO_GPIO;
> +
>  	of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
>  	of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
>  	of_property_read_u32(np, "samsung,i2c-max-bus-freq",
> @@ -1116,6 +1148,9 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
>  	}, {
>  		.name		= "s3c2440-i2c",
>  		.driver_data	= QUIRK_S3C2440,
> +	}, {
> +		.name		= "s3c2440-hdmiphy-i2c",
> +		.driver_data	= QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
>  	}, { },
>  };
>  MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
> -- 
> 1.7.9
> 

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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RE: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Marek Szyprowski]

Hi Wolfram,

On Tuesday, April 17, 2012 7:40 PM Wolfram Sang wrote:

> On Wed, Mar 21, 2012 at 08:11:53PM +0100, Karol Lewandowski wrote:
> > This patch adds support for s3c2440 I2C bus controller dedicated HDMIPHY device on
> > Exynos4 platform. Some quirks are introduced due to differences between HDMIPHY
> > and other I2C controllers on Exynos4.  These differences are:
> > - no GPIOs, HDMIPHY is inside the SoC and the controller is connected
> >   internally
> > - due to unknown reason (probably HW bug in HDMIPHY and/or the controller) a
> >   transfer fails to finish. The controller hangs after sending the last byte,
> >   the workaround for this bug is resetting the controller after each transfer
> >
> > Signed-off-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> > Signed-off-by: Karol Lewandowski <k.lewandowsk@samsung.com>
> > Tested-by: Tomasz Stanislawski <t.stanislaws@samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> > ---
> >  .../devicetree/bindings/i2c/samsung-i2c.txt        |   11 +++++-
> >  drivers/i2c/busses/i2c-s3c2410.c                   |   35 ++++++++++++++++++++
> >  2 files changed, 44 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> > index 38832c7..c6670f9 100644
> > --- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> > +++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
> > @@ -10,14 +10,21 @@ Required properties:
> >      region.
> >    - interrupts: interrupt number to the cpu.
> >    - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
> > -  - gpios: The order of the gpios should be the following: <SDA, SCL>.
> > -    The gpio specifier depends on the gpio controller.
> >
> >  Optional properties:
> > +  - gpios: The order of the gpios should be the following: <SDA, SCL>.
> > +    The gpio specifier depends on the gpio controller. Required in all cases
> > +    except when "samsung,i2c-no-gpio" is also specified.
> > +  - samsung,i2c-no-gpio: input/output lines of the controller are
> > +    permanently wired to the respective client, there are no gpio
> > +    lines that need to be configured to enable this controller
> 
> Can't we just skip this property...

All standard s3c-24x0 i2c controllers require gpio lines for proper operation,
so lack of the gpios property should be considered as an error. However there
is a special case of internal, embedded i2c controller which has no such gpio 
lines at all.

> >    - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
> >      specified, default value is 0.
> >    - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
> >      specified, the default value in Hz is 100000.
> > +  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
> > +    Exynos4 platform - reduce timeout and reset controller after each
> > +    transfer
> 
> ... and this one, if we declare a new compatible-entry for exynos4?

It is not strictly related to Exynos4 SoCs. Exynos4 SoC has 8 standard s3c2440 style
i2c controllers and one additional, internal controller for HDMIPHY, which needs 
some workarounds in the driver. Maybe the quirk should be named 'broken timeout 
detection'

(snipped)

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center

Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 1995 bytes --]


> > >  Optional properties:
> > > +  - gpios: The order of the gpios should be the following: <SDA, SCL>.
> > > +    The gpio specifier depends on the gpio controller. Required in all cases
> > > +    except when "samsung,i2c-no-gpio" is also specified.
> > > +  - samsung,i2c-no-gpio: input/output lines of the controller are
> > > +    permanently wired to the respective client, there are no gpio
> > > +    lines that need to be configured to enable this controller
> > 
> > Can't we just skip this property...
> 
> All standard s3c-24x0 i2c controllers require gpio lines for proper operation,
> so lack of the gpios property should be considered as an error. However there
> is a special case of internal, embedded i2c controller which has no such gpio 
> lines at all.
> 
> > >    - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
> > >      specified, default value is 0.
> > >    - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
> > >      specified, the default value in Hz is 100000.
> > > +  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
> > > +    Exynos4 platform - reduce timeout and reset controller after each
> > > +    transfer
> > 
> > ... and this one, if we declare a new compatible-entry for exynos4?
> 
> It is not strictly related to Exynos4 SoCs. Exynos4 SoC has 8 standard s3c2440 style
> i2c controllers and one additional, internal controller for HDMIPHY, which needs 
> some workarounds in the driver. Maybe the quirk should be named 'broken timeout 
> detection'

I was wondering since you do what I suggested for platform devices already:

+               .name           = "s3c2440-hdmiphy-i2c",
+               .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

On 18.04.2012 15:46, Wolfram Sang wrote:

> 
>>>>  Optional properties:
>>>> +  - gpios: The order of the gpios should be the following: <SDA, SCL>.
>>>> +    The gpio specifier depends on the gpio controller. Required in all cases
>>>> +    except when "samsung,i2c-no-gpio" is also specified.
>>>> +  - samsung,i2c-no-gpio: input/output lines of the controller are
>>>> +    permanently wired to the respective client, there are no gpio
>>>> +    lines that need to be configured to enable this controller
>>>
>>> Can't we just skip this property...
>>
>> All standard s3c-24x0 i2c controllers require gpio lines for proper operation,
>> so lack of the gpios property should be considered as an error. However there
>> is a special case of internal, embedded i2c controller which has no such gpio 
>> lines at all.
>>
>>>>    - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
>>>>      specified, default value is 0.
>>>>    - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
>>>>      specified, the default value in Hz is 100000.
>>>> +  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
>>>> +    Exynos4 platform - reduce timeout and reset controller after each
>>>> +    transfer
>>>
>>> ... and this one, if we declare a new compatible-entry for exynos4?
>>
>> It is not strictly related to Exynos4 SoCs. Exynos4 SoC has 8 standard s3c2440 style
>> i2c controllers and one additional, internal controller for HDMIPHY, which needs 
>> some workarounds in the driver. Maybe the quirk should be named 'broken timeout 
>> detection'
> 
> I was wondering since you do what I suggested for platform devices already:
> 
> +               .name           = "s3c2440-hdmiphy-i2c",
> +               .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,


Here I've done it this way for compatibility with legacy driver and
board(s).

Device tree is new interface, and I thought that it would be better
to describe things explicitly and separately from device type.

Right now these properties are used only on S3C2440, but I don't
consider it highly unlikely to see these on S3C**** in future.

Tomasz had similar doubts when I've posted patch that checked these
quirks only for S3C2440:

  http://permalink.gmane.org/gmane.linux.drivers.i2c/10305

Thus, I've chosen properties and not separate type.

It's easy to introduce compat string (see below), but given above
I'm afraid that we might end up adding -hdmiphy- variant for every
new version of i2c controller.


  E.g.

diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
index c6670f9..b1d106e 100644
--- a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
@@ -6,6 +6,8 @@ Required properties:
   - compatible: value should be either of the following.
       (a) "samsung, s3c2410-i2c", for i2c compatible with s3c2410 i2c.
       (b) "samsung, s3c2440-i2c", for i2c compatible with s3c2440 i2c.
+      (c) "samsung, s3c2440-hdmiphy-i2c", for s3c2440-like i2c used
+          inside HDMIPHY block found on several samsung SoCs
   - reg: physical base address of the controller and length of memory mapped
     region.
   - interrupts: interrupt number to the cpu.
@@ -13,18 +15,13 @@ Required properties:
 
 Optional properties:
   - gpios: The order of the gpios should be the following: <SDA, SCL>.
-    The gpio specifier depends on the gpio controller. Required in all cases
-    except when "samsung,i2c-no-gpio" is also specified.
-  - samsung,i2c-no-gpio: input/output lines of the controller are
-    permanently wired to the respective client, there are no gpio
-    lines that need to be configured to enable this controller
+    The gpio specifier depends on the gpio controller. Required in all
+    cases except for "samsung,i2c-hdmiphy-i2c" whose input/output
+    lines are permanently wired to the respective client
   - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
     specified, default value is 0.
   - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
     specified, the default value in Hz is 100000.
-  - samsung,i2c-quirk-hdmiphy: Quirk for HDMI PHY block found on
-    Exynos4 platform - reduce timeout and reset controller after each
-    transfer
 
 Example:
 
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 71438eb..bc82045 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -106,6 +106,8 @@ MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 static const struct of_device_id s3c24xx_i2c_match[] = {
        { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
        { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
+       { .compatible = "samsung,s3c2440-hdmiphy-i2c",
+         .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
        {},
 };
 MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
@@ -902,12 +904,6 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
 
        pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
 
-       if (of_get_property(np, "samsung,i2c-quirk-hdmiphy", NULL))
-               i2c->quirks |= QUIRK_HDMIPHY;
-
-       if (of_get_property(np, "samsung,i2c-no-gpio", NULL))
-               i2c->quirks |= QUIRK_NO_GPIO;
-
        of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
        of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
        of_property_read_u32(np, "samsung,i2c-max-bus-freq",


Regards,
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform

Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Wolfram Sang]

[-- Attachment #1: Type: text/plain, Size: 2708 bytes --]

Hi Karol,

> >>> ... and this one, if we declare a new compatible-entry for exynos4?
> >>
> >> It is not strictly related to Exynos4 SoCs. Exynos4 SoC has 8 standard s3c2440 style
> >> i2c controllers and one additional, internal controller for HDMIPHY, which needs 
> >> some workarounds in the driver. Maybe the quirk should be named 'broken timeout 
> >> detection'
> > 
> > I was wondering since you do what I suggested for platform devices already:
> > 
> > +               .name           = "s3c2440-hdmiphy-i2c",
> > +               .driver_data    = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
> 
> 
> Here I've done it this way for compatibility with legacy driver and
> board(s).

Understood.

> Device tree is new interface, and I thought that it would be better
> to describe things explicitly and separately from device type.
> 
> Right now these properties are used only on S3C2440, but I don't
> consider it highly unlikely to see these on S3C**** in future.

My experience also says that it easily can get even worse :(

> Tomasz had similar doubts when I've posted patch that checked these
> quirks only for S3C2440:
> 
>   http://permalink.gmane.org/gmane.linux.drivers.i2c/10305
> 
> Thus, I've chosen properties and not separate type.

I understand this reasoning. I still differ, though. Think about my
above example about things getting worse. Then, you'd need another
quirk-property for $FLAW. Later, $FLAW is still there, but the timeout
issue was fixed. That would mean, the poor device-tree making person has
to know which quirks to select for this version of the controller. Just
specifying that it is the HDMI-phy and not a regular I2C controller is
much more convenient, and the driver will figure the rest.

> It's easy to introduce compat string (see below), but given above
> I'm afraid that we might end up adding -hdmiphy- variant for every
> new version of i2c controller.

I'd be fine with that, given that the upcoming hdmiphy versions will not
need all the same set of quirk-flags. I think we want that "quirk lookup
table" fixed in the driver and not encoded in the device tree where
people could get it wrong. Also, the quirks are nothing a board maker
can select from; it is implicit as soons as you want the HDMIPHY on that
SoC, thus the compatible-entry should be enough of a description.

I am not the ultimate expert about bindings, though, and am open for
corrections (I feel kinda confident on this issue, though ;))

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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Re: [PATCH 3/3] i2c-s3c2410: Add HDMIPHY quirk for S3C2440

[Karol Lewandowski]

On 23.04.2012 12:01, Wolfram Sang wrote:

> Hi Karol,
>> Tomasz had similar doubts when I've posted patch that checked these
>> quirks only for S3C2440:
>>
>>   http://permalink.gmane.org/gmane.linux.drivers.i2c/10305
>>
>> Thus, I've chosen properties and not separate type.
> 
> I understand this reasoning. I still differ, though. Think about my
> above example about things getting worse. Then, you'd need another
> quirk-property for $FLAW. Later, $FLAW is still there, but the timeout
> issue was fixed. That would mean, the poor device-tree making person has
> to know which quirks to select for this version of the controller. Just
> specifying that it is the HDMI-phy and not a regular I2C controller is
> much more convenient, and the driver will figure the rest.

>

>> It's easy to introduce compat string (see below), but given above
>> I'm afraid that we might end up adding -hdmiphy- variant for every
>> new version of i2c controller.
> 
> I'd be fine with that, given that the upcoming hdmiphy versions will not
> need all the same set of quirk-flags. I think we want that "quirk lookup
> table" fixed in the driver and not encoded in the device tree where
> people could get it wrong. Also, the quirks are nothing a board maker
> can select from; it is implicit as soons as you want the HDMIPHY on that
> SoC, thus the compatible-entry should be enough of a description.


Fair point, from integrator/board maker POV this makes much more sense.

> I am not the ultimate expert about bindings, though, and am open for
> corrections (I feel kinda confident on this issue, though ;))


I'm quite happy with doing it the way you just described.

I'll resend whole patchset in a minute.

Thanks!
-- 
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform