Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-17 Thread Tushar Behera
On 08/16/2012 10:05 PM, Thomas Abraham wrote:
 Add device tree based discovery support for Samsung's sdhci controller
 
 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
 Changes since v3:
 
 The patch series that adds device tree support for Samsung sdhci controller
 had six patches in total, of which, the first five patches have been accepted.
 The sixth patch in the series was dropped since it was using custom Samsung
 properties for descrbing the bus-width and card-detect gpio, but had otherwise
 addressed all the comments.
 
 This patch reworks the sixth patch in v3 of the sdhci device tree support
 patch series. The only change in this patch from the v3 version is the use of
 generic mmc bindings for descrbing the bus-width and card-detect gpio.
 
  .../devicetree/bindings/mmc/samsung-sdhci.txt  |   51 +++
  drivers/mmc/host/sdhci-s3c.c   |  146 
 +++-
  2 files changed, 191 insertions(+), 6 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 
 diff --git a/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt 
 b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 new file mode 100644
 index 000..398540b
 --- /dev/null
 +++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 @@ -0,0 +1,51 @@
 +* Samsung's SDHCI Controller device tree bindings
 +
 +Samsung's SDHCI controller is used as a connectivity interface with external
 +MMC, SD and eMMC storage mediums. This file documents differences between the
 +core mmc properties described by mmc.txt and the properties used by the
 +Samsung implmentation of the SDHCI controller.
 +
 +Required SoC Specific Properties:
 +- compatible: should be one of the following
 +  - samsung,s3c6410-sdhci: For controllers compatible with s3c6410 sdhci
 +controller.
 +  - samsung,exynos4210-sdhci: For controllers compatible with Exynos4 sdhci
 +controller.
 +
 +Required Board Specific Properties:
 +- gpios: Should specify the gpios used for clock, command and data lines. The
 +  gpio specifier format depends on the gpio controller.
 +
 +Optional Board Specific Properties:
 +- One of the following properties for card detect type.
 +  - samsung,sdhci-cd-internal: Card detect line from the card slot  is
 +connected to the card detect pad of the sdhci controller. A gpio is
 +used for this connection (with possible pin function settings).
 +  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
 +is used a card detect line. This gpio line is not connected to card 
 detect
 +pad of the sdhci controller.
 +  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
 +detect the presence of the card. (DEFAULT, if no card detect property
 +is specified).
 +  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
 +permanently connected to the sdhci controller.
 +
 +Example:
 + sdhci@1253 {
 + compatible = samsung,exynos4210-sdhci;
 + reg = 0x1253 0x100;
 + interrupts = 0 75 0;

Typo: interrupts = 0 75 0;

 + bus-width = 4;
 + samsung,sdhci-cd-internal;
 + cd-gpios = gpk2 2 2 3 3;
 + gpios = gpk2 0 2 0 3,  /* clock line */
 + gpk2 1 2 0 3,  /* command line */
 + gpk2 3 2 3 3,  /* data line 0 */
 + gpk2 4 2 3 3,  /* data line 1 */
 + gpk2 5 2 3 3,  /* data line 2 */
 + gpk2 6 2 3 3;  /* data line 3 */
 + };
 +
 + Note: This example shows both SoC specific and board specific properties
 + in a single device node. The properties can be actually be seperated
 + into SoC specific node and board specific node.
 diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
 index a50c205..7fcc642 100644
 --- a/drivers/mmc/host/sdhci-s3c.c
 +++ b/drivers/mmc/host/sdhci-s3c.c
 @@ -34,6 +34,9 @@
  
  #define MAX_BUS_CLK  (4)
  
 +/* Number of gpio's used is max data bus width + command and clock lines */
 +#define NUM_GPIOS(x) (x + 2)
 +
  /**
   * struct sdhci_s3c - S3C SDHCI instance
   * @host: The SDHCI host created
 @@ -41,6 +44,7 @@
   * @ioarea: The resource created when we claimed the IO area.
   * @pdata: The platform data for this controller.
   * @cur_clk: The index of the current bus clock.
 + * @gpios: List of gpio numbers parsed from device tree.
   * @clk_io: The clock for the internal bus interface.
   * @clk_bus: The clocks that are available for the SD/MMC bus clock.
   */
 @@ -52,6 +56,7 @@ struct sdhci_s3c {
   unsigned intcur_clk;
   int ext_cd_irq;
   int ext_cd_gpio;
 + int *gpios;
  
   struct clk  *clk_io;
   struct clk  

Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-17 Thread Heiko Stübner
Hi Thomas,

Am Donnerstag, 16. August 2012, 17:49:29 schrieb Thomas Abraham:
 Add device tree based discovery support for Samsung's sdhci controller
 
 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
  drivers/mmc/host/sdhci-s3c.c |  146
 -- 1 files changed, 140
 insertions(+), 6 deletions(-)
 
 diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
 index a50c205..7fcc642 100644
 --- a/drivers/mmc/host/sdhci-s3c.c
 +++ b/drivers/mmc/host/sdhci-s3c.c

[...]

 @@ -737,6 +860,16 @@ static struct platform_device_id
 sdhci_s3c_driver_ids[] = { };
  MODULE_DEVICE_TABLE(platform, sdhci_s3c_driver_ids);
 
 +#ifdef CONFIG_OF
 +static const struct of_device_id sdhci_s3c_dt_match[] = {
 + { .compatible = samsung,s3c6410-sdhci, },
 + { .compatible = samsung,exynos4210-sdhci,
 + .data = exynos4_sdhci_drv_data },

Please use the EXYNOS4_SDHCI_DRV_DATA constant here. Otherwise other Samsung 
platforms experimenting with dt will break.


Thanks
Heiko
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[PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Thomas Abraham
Add device tree based discovery support for Samsung's sdhci controller

Cc: Ben Dooks ben-li...@fluff.org
Cc: Kukjin Kim kgene@samsung.com
Cc: Chris Ball c...@laptop.org
Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
---
 drivers/mmc/host/sdhci-s3c.c |  146 --
 1 files changed, 140 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
index a50c205..7fcc642 100644
--- a/drivers/mmc/host/sdhci-s3c.c
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -34,6 +34,9 @@
 
 #define MAX_BUS_CLK(4)
 
+/* Number of gpio's used is max data bus width + command and clock lines */
+#define NUM_GPIOS(x)   (x + 2)
+
 /**
  * struct sdhci_s3c - S3C SDHCI instance
  * @host: The SDHCI host created
@@ -41,6 +44,7 @@
  * @ioarea: The resource created when we claimed the IO area.
  * @pdata: The platform data for this controller.
  * @cur_clk: The index of the current bus clock.
+ * @gpios: List of gpio numbers parsed from device tree.
  * @clk_io: The clock for the internal bus interface.
  * @clk_bus: The clocks that are available for the SD/MMC bus clock.
  */
@@ -52,6 +56,7 @@ struct sdhci_s3c {
unsigned intcur_clk;
int ext_cd_irq;
int ext_cd_gpio;
+   int *gpios;
 
struct clk  *clk_io;
struct clk  *clk_bus[MAX_BUS_CLK];
@@ -419,9 +424,109 @@ static void sdhci_s3c_setup_card_detect_gpio(struct 
sdhci_s3c *sc)
}
 }
 
+#ifdef CONFIG_OF
+static int __devinit sdhci_s3c_parse_dt(struct device *dev,
+   struct sdhci_host *host, struct s3c_sdhci_platdata *pdata)
+{
+   struct device_node *node = dev-of_node;
+   struct sdhci_s3c *ourhost = to_s3c(host);
+   u32 max_width;
+   int gpio, cnt, ret;
+
+   /* if the bus-width property is not specified, assume width as 1 */
+   if (of_property_read_u32(node, bus-width, max_width))
+   max_width = 1;
+   pdata-max_width = max_width;
+
+   ourhost-gpios = devm_kzalloc(dev, NUM_GPIOS(pdata-max_width) *
+   sizeof(int), GFP_KERNEL);
+   if (!ourhost-gpios)
+   return -ENOMEM;
+
+   /* get the card detection method */
+   if (of_get_property(node, samsung,sdhci-cd-internal, NULL))
+   pdata-cd_type = S3C_SDHCI_CD_INTERNAL;
+   else if (of_get_property(node, samsung,sdhci-cd-gpio, NULL))
+   pdata-cd_type = S3C_SDHCI_CD_GPIO;
+   else if (of_get_property(node, samsung,sdhci-cd-none, NULL))
+   pdata-cd_type = S3C_SDHCI_CD_NONE;
+   else if (of_get_property(node, samsung,sdhci-cd-permanent, NULL))
+   pdata-cd_type = S3C_SDHCI_CD_PERMANENT;
+   else
+   pdata-cd_type = S3C_SDHCI_CD_NONE;
+
+   /* get the gpio used for card detection */
+   if (pdata-cd_type == S3C_SDHCI_CD_GPIO ||
+   pdata-cd_type == S3C_SDHCI_CD_INTERNAL) {
+   gpio = of_get_named_gpio(node, cd-gpios, 0);
+   if (!gpio_is_valid(gpio)) {
+   dev_err(dev, invalid card detect gpio specified\n);
+   return -EINVAL;
+   }
+   }
+
+   if (pdata-cd_type == S3C_SDHCI_CD_GPIO) {
+   pdata-ext_cd_gpio = gpio;
+   ourhost-ext_cd_gpio = -1;
+   if (of_get_property(node, cd-inverted, NULL))
+   pdata-ext_cd_gpio_invert = 1;
+   } else if (pdata-cd_type == S3C_SDHCI_CD_INTERNAL) {
+   ret = gpio_request(gpio, sdhci-cd);
+   if (ret) {
+   dev_err(dev, card detect gpio request failed\n);
+   return -EINVAL;
+   }
+   ourhost-ext_cd_gpio = gpio;
+   }
+
+   /* get the gpios for command, clock and data lines */
+   for (cnt = 0; cnt  NUM_GPIOS(pdata-max_width); cnt++) {
+   gpio = of_get_gpio(node, cnt);
+   if (!gpio_is_valid(gpio)) {
+   dev_err(dev, invalid gpio[%d]\n, cnt);
+   goto err_free_dt_cd_gpio;
+   }
+   ourhost-gpios[cnt] = gpio;
+   }
+
+   for (cnt = 0; cnt  NUM_GPIOS(pdata-max_width); cnt++) {
+   ret = gpio_request(ourhost-gpios[cnt], sdhci-gpio);
+   if (ret) {
+   dev_err(dev, gpio[%d] request failed\n, cnt);
+   goto err_free_dt_gpios;
+   }
+   }
+
+   return 0;
+
+ err_free_dt_gpios:
+   while (--cnt = 0)
+   gpio_free(ourhost-gpios[cnt]);
+ err_free_dt_cd_gpio:
+   if (pdata-cd_type == S3C_SDHCI_CD_INTERNAL)
+   gpio_free(ourhost-ext_cd_gpio);
+   return -EINVAL;
+}
+#else
+static int __devinit sdhci_s3c_parse_dt(struct device *dev,
+   struct sdhci_host *host, struct s3c_sdhci_platdata *pdata)
+{
+   

Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Chris Ball
Hi Thomas,

On Thu, Aug 16 2012, Thomas Abraham wrote:
 Add device tree based discovery support for Samsung's sdhci controller

 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
  drivers/mmc/host/sdhci-s3c.c |  146 
 --
  1 files changed, 140 insertions(+), 6 deletions(-)

I know your initial version was submitted before we adopted a set of
standard MMC DT bindings, but now that those bindings exist this code
should be using them -- there should be a new file:
   Documentation/devicetree/bindings/mmc/sdhci-s3c.txt
describing differences between the mmc.txt bindings and this driver's.

Also, you didn't include a patch changelog, so I can't tell whether this
contains changes against your v3 of this patch; please do that.

Thanks!

- Chris.
-- 
Chris Ball   c...@laptop.org   http://printf.net/
One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Thomas Abraham
Hi Chris,

Thanks for your review.

On 16 August 2012 21:17, Chris Ball c...@laptop.org wrote:
 Hi Thomas,

 On Thu, Aug 16 2012, Thomas Abraham wrote:
 Add device tree based discovery support for Samsung's sdhci controller

 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
  drivers/mmc/host/sdhci-s3c.c |  146 
 --
  1 files changed, 140 insertions(+), 6 deletions(-)

 I know your initial version was submitted before we adopted a set of
 standard MMC DT bindings, but now that those bindings exist this code
 should be using them -- there should be a new file:
Documentation/devicetree/bindings/mmc/sdhci-s3c.txt
 describing differences between the mmc.txt bindings and this driver's.

Sorry, I missed that. I will resend this patch with the documentation.


 Also, you didn't include a patch changelog, so I can't tell whether this
 contains changes against your v3 of this patch; please do that.

Yes, I missed the changelog as well. I will add it in the next version
of this patch.

Thanks,
Thomas.


 Thanks!

 - Chris.
 --
 Chris Ball   c...@laptop.org   http://printf.net/
 One Laptop Per Child
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[PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Thomas Abraham
Add device tree based discovery support for Samsung's sdhci controller

Cc: Ben Dooks ben-li...@fluff.org
Cc: Kukjin Kim kgene@samsung.com
Cc: Chris Ball c...@laptop.org
Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
---
Changes since v3:

The patch series that adds device tree support for Samsung sdhci controller
had six patches in total, of which, the first five patches have been accepted.
The sixth patch in the series was dropped since it was using custom Samsung
properties for descrbing the bus-width and card-detect gpio, but had otherwise
addressed all the comments.

This patch reworks the sixth patch in v3 of the sdhci device tree support
patch series. The only change in this patch from the v3 version is the use of
generic mmc bindings for descrbing the bus-width and card-detect gpio.

 .../devicetree/bindings/mmc/samsung-sdhci.txt  |   51 +++
 drivers/mmc/host/sdhci-s3c.c   |  146 +++-
 2 files changed, 191 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/samsung-sdhci.txt

diff --git a/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt 
b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
new file mode 100644
index 000..398540b
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
@@ -0,0 +1,51 @@
+* Samsung's SDHCI Controller device tree bindings
+
+Samsung's SDHCI controller is used as a connectivity interface with external
+MMC, SD and eMMC storage mediums. This file documents differences between the
+core mmc properties described by mmc.txt and the properties used by the
+Samsung implmentation of the SDHCI controller.
+
+Required SoC Specific Properties:
+- compatible: should be one of the following
+  - samsung,s3c6410-sdhci: For controllers compatible with s3c6410 sdhci
+controller.
+  - samsung,exynos4210-sdhci: For controllers compatible with Exynos4 sdhci
+controller.
+
+Required Board Specific Properties:
+- gpios: Should specify the gpios used for clock, command and data lines. The
+  gpio specifier format depends on the gpio controller.
+
+Optional Board Specific Properties:
+- One of the following properties for card detect type.
+  - samsung,sdhci-cd-internal: Card detect line from the card slot  is
+connected to the card detect pad of the sdhci controller. A gpio is
+used for this connection (with possible pin function settings).
+  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
+is used a card detect line. This gpio line is not connected to card detect
+pad of the sdhci controller.
+  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
+detect the presence of the card. (DEFAULT, if no card detect property
+is specified).
+  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
+permanently connected to the sdhci controller.
+
+Example:
+   sdhci@1253 {
+   compatible = samsung,exynos4210-sdhci;
+   reg = 0x1253 0x100;
+   interrupts = 0 75 0;
+   bus-width = 4;
+   samsung,sdhci-cd-internal;
+   cd-gpios = gpk2 2 2 3 3;
+   gpios = gpk2 0 2 0 3,  /* clock line */
+   gpk2 1 2 0 3,  /* command line */
+   gpk2 3 2 3 3,  /* data line 0 */
+   gpk2 4 2 3 3,  /* data line 1 */
+   gpk2 5 2 3 3,  /* data line 2 */
+   gpk2 6 2 3 3;  /* data line 3 */
+   };
+
+   Note: This example shows both SoC specific and board specific properties
+   in a single device node. The properties can be actually be seperated
+   into SoC specific node and board specific node.
diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
index a50c205..7fcc642 100644
--- a/drivers/mmc/host/sdhci-s3c.c
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -34,6 +34,9 @@
 
 #define MAX_BUS_CLK(4)
 
+/* Number of gpio's used is max data bus width + command and clock lines */
+#define NUM_GPIOS(x)   (x + 2)
+
 /**
  * struct sdhci_s3c - S3C SDHCI instance
  * @host: The SDHCI host created
@@ -41,6 +44,7 @@
  * @ioarea: The resource created when we claimed the IO area.
  * @pdata: The platform data for this controller.
  * @cur_clk: The index of the current bus clock.
+ * @gpios: List of gpio numbers parsed from device tree.
  * @clk_io: The clock for the internal bus interface.
  * @clk_bus: The clocks that are available for the SD/MMC bus clock.
  */
@@ -52,6 +56,7 @@ struct sdhci_s3c {
unsigned intcur_clk;
int ext_cd_irq;
int ext_cd_gpio;
+   int *gpios;
 
struct clk  *clk_io;
struct clk  *clk_bus[MAX_BUS_CLK];
@@ -419,9 +424,109 @@ static void sdhci_s3c_setup_card_detect_gpio(struct 
sdhci_s3c *sc)
}
 }
 
+#ifdef CONFIG_OF

Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Chris Ball
Hi,

On Thu, Aug 16 2012, Thomas Abraham wrote:
 Add device tree based discovery support for Samsung's sdhci controller

 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
 Changes since v3:

 The patch series that adds device tree support for Samsung sdhci controller
 had six patches in total, of which, the first five patches have been accepted.
 The sixth patch in the series was dropped since it was using custom Samsung
 properties for descrbing the bus-width and card-detect gpio, but had otherwise
 addressed all the comments.

 This patch reworks the sixth patch in v3 of the sdhci device tree support
 patch series. The only change in this patch from the v3 version is the use of
 generic mmc bindings for descrbing the bus-width and card-detect gpio.

  .../devicetree/bindings/mmc/samsung-sdhci.txt  |   51 +++
  drivers/mmc/host/sdhci-s3c.c   |  146 
 +++-
  2 files changed, 191 insertions(+), 6 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/mmc/samsung-sdhci.txt

 diff --git a/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt 
 b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 new file mode 100644
 index 000..398540b
 --- /dev/null
 +++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 @@ -0,0 +1,51 @@
 +* Samsung's SDHCI Controller device tree bindings
 +
 +Samsung's SDHCI controller is used as a connectivity interface with external
 +MMC, SD and eMMC storage mediums. This file documents differences between the
 +core mmc properties described by mmc.txt and the properties used by the
 +Samsung implmentation of the SDHCI controller.
 +
 +Required SoC Specific Properties:
 +- compatible: should be one of the following
 +  - samsung,s3c6410-sdhci: For controllers compatible with s3c6410 sdhci
 +controller.
 +  - samsung,exynos4210-sdhci: For controllers compatible with Exynos4 sdhci
 +controller.
 +
 +Required Board Specific Properties:
 +- gpios: Should specify the gpios used for clock, command and data lines. The
 +  gpio specifier format depends on the gpio controller.
 +
 +Optional Board Specific Properties:
 +- One of the following properties for card detect type.
 +  - samsung,sdhci-cd-internal: Card detect line from the card slot  is
 +connected to the card detect pad of the sdhci controller. A gpio is
 +used for this connection (with possible pin function settings).
 +  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
 +is used a card detect line. This gpio line is not connected to card 
 detect
 +pad of the sdhci controller.
 +  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
 +detect the presence of the card. (DEFAULT, if no card detect property
 +is specified).
 +  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
 +permanently connected to the sdhci controller.
 +
 +Example:
 + sdhci@1253 {
 + compatible = samsung,exynos4210-sdhci;
 + reg = 0x1253 0x100;
 + interrupts = 0 75 0;
 + bus-width = 4;
 + samsung,sdhci-cd-internal;
 + cd-gpios = gpk2 2 2 3 3;
 + gpios = gpk2 0 2 0 3,  /* clock line */
 + gpk2 1 2 0 3,  /* command line */
 + gpk2 3 2 3 3,  /* data line 0 */
 + gpk2 4 2 3 3,  /* data line 1 */
 + gpk2 5 2 3 3,  /* data line 2 */
 + gpk2 6 2 3 3;  /* data line 3 */
 + };
 +
 + Note: This example shows both SoC specific and board specific properties
 + in a single device node. The properties can be actually be seperated
 + into SoC specific node and board specific node.

Looks good, except the text file doesn't mention anywhere that it describes
the bindings used by sdhci-s3c.c -- that could be useful information to
someone reading the binding and trying to discover which driver uses it.

Maybe we can call the text file sdhci-s3c.txt?  Or samsung,sdhci-s3c.txt
if you prefer.

Thanks,

- Chris.
-- 
Chris Ball   c...@laptop.org   http://printf.net/
One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Thomas Abraham
On 16 August 2012 21:59, Chris Ball c...@laptop.org wrote:
 Hi,

 On Thu, Aug 16 2012, Thomas Abraham wrote:
 Add device tree based discovery support for Samsung's sdhci controller

 Cc: Ben Dooks ben-li...@fluff.org
 Cc: Kukjin Kim kgene@samsung.com
 Cc: Chris Ball c...@laptop.org
 Signed-off-by: Thomas Abraham thomas.abra...@linaro.org
 ---
 Changes since v3:

 The patch series that adds device tree support for Samsung sdhci controller
 had six patches in total, of which, the first five patches have been 
 accepted.
 The sixth patch in the series was dropped since it was using custom Samsung
 properties for descrbing the bus-width and card-detect gpio, but had 
 otherwise
 addressed all the comments.

 This patch reworks the sixth patch in v3 of the sdhci device tree support
 patch series. The only change in this patch from the v3 version is the use of
 generic mmc bindings for descrbing the bus-width and card-detect gpio.

  .../devicetree/bindings/mmc/samsung-sdhci.txt  |   51 +++
  drivers/mmc/host/sdhci-s3c.c   |  146 
 +++-
  2 files changed, 191 insertions(+), 6 deletions(-)
  create mode 100644 Documentation/devicetree/bindings/mmc/samsung-sdhci.txt

 diff --git a/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt 
 b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 new file mode 100644
 index 000..398540b
 --- /dev/null
 +++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
 @@ -0,0 +1,51 @@
 +* Samsung's SDHCI Controller device tree bindings
 +
 +Samsung's SDHCI controller is used as a connectivity interface with external
 +MMC, SD and eMMC storage mediums. This file documents differences between 
 the
 +core mmc properties described by mmc.txt and the properties used by the
 +Samsung implmentation of the SDHCI controller.
 +
 +Required SoC Specific Properties:
 +- compatible: should be one of the following
 +  - samsung,s3c6410-sdhci: For controllers compatible with s3c6410 sdhci
 +controller.
 +  - samsung,exynos4210-sdhci: For controllers compatible with Exynos4 
 sdhci
 +controller.
 +
 +Required Board Specific Properties:
 +- gpios: Should specify the gpios used for clock, command and data lines. 
 The
 +  gpio specifier format depends on the gpio controller.
 +
 +Optional Board Specific Properties:
 +- One of the following properties for card detect type.
 +  - samsung,sdhci-cd-internal: Card detect line from the card slot  is
 +connected to the card detect pad of the sdhci controller. A gpio is
 +used for this connection (with possible pin function settings).
 +  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
 +is used a card detect line. This gpio line is not connected to card 
 detect
 +pad of the sdhci controller.
 +  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
 +detect the presence of the card. (DEFAULT, if no card detect property
 +is specified).
 +  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
 +permanently connected to the sdhci controller.
 +
 +Example:
 + sdhci@1253 {
 + compatible = samsung,exynos4210-sdhci;
 + reg = 0x1253 0x100;
 + interrupts = 0 75 0;
 + bus-width = 4;
 + samsung,sdhci-cd-internal;
 + cd-gpios = gpk2 2 2 3 3;
 + gpios = gpk2 0 2 0 3,  /* clock line */
 + gpk2 1 2 0 3,  /* command line */
 + gpk2 3 2 3 3,  /* data line 0 */
 + gpk2 4 2 3 3,  /* data line 1 */
 + gpk2 5 2 3 3,  /* data line 2 */
 + gpk2 6 2 3 3;  /* data line 3 */
 + };
 +
 + Note: This example shows both SoC specific and board specific 
 properties
 + in a single device node. The properties can be actually be seperated
 + into SoC specific node and board specific node.

 Looks good, except the text file doesn't mention anywhere that it describes
 the bindings used by sdhci-s3c.c -- that could be useful information to
 someone reading the binding and trying to discover which driver uses it.

 Maybe we can call the text file sdhci-s3c.txt?  Or samsung,sdhci-s3c.txt
 if you prefer.

Hi Chris,

The assumption here was that the all the binding documentation have to
be generic enough to be useful for non-linux platforms as well. And
there were previous discussions on actually moving the binding
documentation outside of the linux source and maintained separately.

Hence, the text file states that it describes the bindings used by
Samsung's SDHCI controller. If you prefer, I can resubmit this patch
with samsung,sdhci-s3c.txt as the file name for the bindings
documentation file.

Thanks,
Thomas.


 Thanks,

 - Chris.
 --
 Chris Ball   c...@laptop.org   http://printf.net/
 One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Chris Ball
Hi Thomas,

On Thu, Aug 16 2012, Thomas Abraham wrote:
 +Optional Board Specific Properties:
 +- One of the following properties for card detect type.
 +  - samsung,sdhci-cd-internal: Card detect line from the card slot is
 +connected to the card detect pad of the sdhci controller. A gpio is
 +used for this connection (with possible pin function settings).
 +  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
 +is used a card detect line. This gpio line is not connected to card 
 detect
 +pad of the sdhci controller.
 +  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
 +detect the presence of the card. (DEFAULT, if no card detect property
 +is specified).
 +  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
 +permanently connected to the sdhci controller.

sdhci-s3c isn't the only driver that's going to have options for
different cd configurations -- maybe now is the right time to move
these options into the core bindings?

At OLPC we've just started using:

 * broken-cd to mean samsung,sdhci-cd-none,
 
 * the presence of a cd-gpios property to imply samsung,sdhci-cd-gpio.
   
 * non-removable to mean samsung,sdhci-cd-permanent (this is already
   specified in mmc.txt)

Would these work for you?

We don't have a distinction between sdhci-cd-internal and sdhci-cd-gpio,
and I'm having trouble working out why one is necessary.  Why does the
driver need to know where the gpio came from, aside from knowing which
gpio it is and whether it needs to be inverted (with cd-inverted)?

Thanks,

- Chris.
-- 
Chris Ball   c...@laptop.org   http://printf.net/
One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

2012-08-16 Thread Thomas Abraham
On 16 August 2012 22:22, Chris Ball c...@laptop.org wrote:
 Hi Thomas,

 On Thu, Aug 16 2012, Thomas Abraham wrote:
 +Optional Board Specific Properties:
 +- One of the following properties for card detect type.
 +  - samsung,sdhci-cd-internal: Card detect line from the card slot is
 +connected to the card detect pad of the sdhci controller. A gpio is
 +used for this connection (with possible pin function settings).
 +  - samsung,sdhci-cd-gpio: A gpio line (with possible pin function settings)
 +is used a card detect line. This gpio line is not connected to card 
 detect
 +pad of the sdhci controller.
 +  - samsung,sdhci-cd-none: There is no card detect line. Polling is used to
 +detect the presence of the card. (DEFAULT, if no card detect property
 +is specified).
 +  - samsung,sdhci-cd-permanent: There is no card detect line. The card is
 +permanently connected to the sdhci controller.

 sdhci-s3c isn't the only driver that's going to have options for
 different cd configurations -- maybe now is the right time to move
 these options into the core bindings?

Yes, I agree. It will be better to reduce the custom bindings.


 At OLPC we've just started using:

  * broken-cd to mean samsung,sdhci-cd-none,

Yes, they are mean the same.


  * the presence of a cd-gpios property to imply samsung,sdhci-cd-gpio.

samsung,sdhci-cd-gpio and sdhci-cd-internal both use the cd-gpio line.

samsung,sdhci-cd-gpio means that the cd-gpio line is not connected
to the card-detect pad of the sdhci controller. Instead, it identifies
cd-gpio as a gpio pin, connected to the card-detect pin of the card
slot and it can used as a source of external interrupt. The driver
can register card insert/remove handler for this interrupt and get
notified about the changes in card state.

sdhci-cd-internal means that the cd-gpio line is used to connect
the card-detect pin of the card slot and the card-detect pad of the
sdhci controller. The controller is then aware of any changes in card
state and the controller generates appropriate interrupts to notify
changes in card-state.


  * non-removable to mean samsung,sdhci-cd-permanent (this is already
specified in mmc.txt)

Ok.


 Would these work for you?

Yes, the first and the third works, but the second point needs a way
to identify the type of external card-detection mechanism.


 We don't have a distinction between sdhci-cd-internal and sdhci-cd-gpio,
 and I'm having trouble working out why one is necessary.  Why does the
 driver need to know where the gpio came from, aside from knowing which
 gpio it is and whether it needs to be inverted (with cd-inverted)?

This is as explained above. Maybe other controllers also need
something similar to samsung,sdhci-cd-gpio and sdhci-cd-internal.
And so, we could make a generic binding for these as well.

Thanks,
Thomas.
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