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

[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 
> Cc: Kukjin Kim 
> Cc: Chris Ball 
> Signed-off-by: Thomas Abraham 
> ---
>  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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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

[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 
> Cc: Kukjin Kim 
> Cc: Chris Ball 
> Signed-off-by: Thomas Abraham 
> ---
> 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;
>  
>   s

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

[Thomas Abraham]

On 16 August 2012 22:22, Chris Ball  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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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

[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  
One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

[Thomas Abraham]

On 16 August 2012 21:59, Chris Ball  wrote:
> Hi,
>
> On Thu, Aug 16 2012, Thomas Abraham wrote:
>> Add device tree based discovery support for Samsung's sdhci controller
>>
>> Cc: Ben Dooks 
>> Cc: Kukjin Kim 
>> Cc: Chris Ball 
>> Signed-off-by: Thomas Abraham 
>> ---
>> 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  
> One Lap

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

[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 
> Cc: Kukjin Kim 
> Cc: Chris Ball 
> Signed-off-by: Thomas Abraham 
> ---
> 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  
One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

[Thomas Abraham]

Hi Chris,

Thanks for your review.

On 16 August 2012 21:17, Chris Ball  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 
>> Cc: Kukjin Kim 
>> Cc: Chris Ball 
>> Signed-off-by: Thomas Abraham 
>> ---
>>  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  
> One Laptop Per Child
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Re: [PATCH] mmc: sdhci-s3c: Add device tree support

[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 
> Cc: Kukjin Kim 
> Cc: Chris Ball 
> Signed-off-by: Thomas Abraham 
> ---
>  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  
One Laptop Per Child
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