[PATCH v5] mmc: sdhci-s3c: Add device tree support

Thomas Abraham thomas.abraham at linaro.org
Fri Aug 24 13:59:38 EST 2012


On 24 August 2012 05:28, Jaehoon Chung <jh80.chung at samsung.com> wrote:
> On 08/24/2012 02:10 AM, Thomas Abraham wrote:
>> Add device tree based discovery support for Samsung's sdhci controller
>>
>> Cc: Ben Dooks <ben-linux at fluff.org>
>> Cc: Kukjin Kim <kgene.kim at samsung.com>
>> Cc: Chris Ball <cjb at laptop.org>
>> Signed-off-by: Thomas Abraham <thomas.abraham at linaro.org>
>> ---
>> Changes since v4:
>> Adapted to new mmc core card detection bindings as specfied in the patch:
>> [PATCH] mmc: dt: Add card-detection properties to core binding
>> and extends it "samsung,cd-pinmux-gpio" property as suggested by
>> Mitch Bradley <wmb at firmworks.com>
>>
>> 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      |   53 +++++++
>>  drivers/mmc/host/sdhci-s3c.c                       |  162 +++++++++++++++++++-
>>  2 files changed, 209 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 0000000..361c2ee
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mmc/samsung-sdhci.txt
>> @@ -0,0 +1,53 @@
>> +* 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.
>> +
>> +Note: The mmc core bindings documentation states that if none of the core
>> +card-detect bindings are used, then the standard sdhci card detect mechanism
>> +is used. The Samsung's SDHCI controller bindings extends this as listed below.
>> +
>> +[A] The property "samsung,cd-pinmux-gpio" can be used as stated in the
>> +    "Optional Board Specific Properties" section below.
>> +
>> +[B] If core card-detect bindings and "samsung,cd-pinmux-gpio" property
>> +    is not specified, it is assumed that there is no card detection
>> +    mechanism used.
>> +
>> +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:
>> +- samsung,cd-pinmux-gpio: Specifies the card detect line that is routed
>> +  through a pinmux to the card-detect pin of the card slot. This property
>> +  should be used only if none of the mmc core card-detect properties are
>> +  used.
>> +
>> +Example:
>> +     sdhci at 12530000 {
>> +             compatible = "samsung,exynos4210-sdhci";
>> +             reg = <0x12530000 0x100>;
>> +             interrupts = <0 75 0>;
>> +             bus-width = <4>;
>> +             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..445910e 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 int            cur_clk;
>>       int                     ext_cd_irq;
>>       int                     ext_cd_gpio;
>> +     int                     *gpios;
>>
>>       struct clk              *clk_io;
>>       struct clk              *clk_bus[MAX_BUS_CLK];
>> @@ -419,9 +424,125 @@ 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, "broken-cd", 0)) {
>> +             pdata->cd_type = S3C_SDHCI_CD_NONE;
>> +             goto setup_bus;
>> +     }
> If gpio_name didn't match with anything, it should be used the S3C_SDHCI_CD_NONE by default.
> What reason need to check this condition?

If none of the card-detect bindings are found (broken-cd,
non-removable, cd-gpios or samsung,cd-pinmux-gpio), then the card
detect type is set as S3C_SDHCI_CD_NONE. But for that, the search for
all these bindings have to be first completed. I hope I have answered
you question, if not, please let me know, I might have misunderstood
your question.

>> +
>> +     if (of_get_property(node, "non-removable", 0)) {
>> +             pdata->cd_type = S3C_SDHCI_CD_PERMANENT;
>> +             goto setup_bus;
>> +     }
>> +
>> +     gpio = of_get_named_gpio(node, "cd-gpios", 0);
>> +     if (gpio_is_valid(gpio)) {
>> +             pdata->cd_type = S3C_SDHCI_CD_GPIO;
>> +             goto found_cd;
>> +     } else {
>> +             if (gpio != -ENOENT) {
>> +                     dev_err(dev, "invalid card detect gpio specified\n");
>> +                     return -EINVAL;
>> +             }
>> +     }
> Can use "else if (gpio != -ENOENT)"

Ok. Thanks.

>> +
>> +     gpio = of_get_named_gpio(node, "samsung,cd-pinmux-gpio", 0);
>> +     if (gpio_is_valid(gpio)) {
>> +             pdata->cd_type = S3C_SDHCI_CD_INTERNAL;
>> +             goto found_cd;
>> +     } else {
>> +             if (gpio != -ENOENT) {
>> +                     dev_err(dev, "invalid card detect gpio specified\n");
>> +                     return -EINVAL;
>> +             }
>> +     }
>> +
>> +     dev_info(dev, "assuming no card detect line available\n");
>> +     pdata->cd_type = S3C_SDHCI_CD_NONE;
>> +
>> + found_cd:
>> +     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;
>> +     }
>> +
>> + setup_bus:
>> +     /* 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)
>> +{
>> +     return -EINVAL;
>> +}
>> +#endif
>> +
>> +static const struct of_device_id sdhci_s3c_dt_match[];
>> +
>>  static inline struct sdhci_s3c_drv_data *sdhci_s3c_get_driver_data(
>>                       struct platform_device *pdev)
>>  {
>> +#ifdef CONFIG_OF
>> +     if (pdev->dev.of_node) {
>> +             const struct of_device_id *match;
>> +             match = of_match_node(sdhci_s3c_dt_match, pdev->dev.of_node);
>> +             return (struct sdhci_s3c_drv_data *)match->data;
>> +     }
>> +#endif
>>       return (struct sdhci_s3c_drv_data *)
>>                       platform_get_device_id(pdev)->driver_data;
>>  }
>> @@ -436,7 +557,7 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>       struct resource *res;
>>       int ret, irq, ptr, clks;
>>
>> -     if (!pdev->dev.platform_data) {
>> +     if (!pdev->dev.platform_data && !pdev->dev.of_node) {
>>               dev_err(dev, "no device data specified\n");
>>               return -ENOENT;
>>       }
>> @@ -452,21 +573,28 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>               dev_err(dev, "sdhci_alloc_host() failed\n");
>>               return PTR_ERR(host);
>>       }
>> +     sc = sdhci_priv(host);
>>
>>       pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
>>       if (!pdata) {
>>               ret = -ENOMEM;
>> -             goto err_io_clk;
>> +             goto err_pdata;
>> +     }
>> +
>> +     if (pdev->dev.of_node) {
>> +             ret = sdhci_s3c_parse_dt(&pdev->dev, host, pdata);
>> +             if (ret)
>> +                     goto err_pdata;
>> +     } else {
>> +             memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
>> +             sc->ext_cd_gpio = -1; /* invalid gpio number */
>>       }
>> -     memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
>>
>>       drv_data = sdhci_s3c_get_driver_data(pdev);
>> -     sc = sdhci_priv(host);
>>
>>       sc->host = host;
>>       sc->pdev = pdev;
>>       sc->pdata = pdata;
>> -     sc->ext_cd_gpio = -1; /* invalid gpio number */
>>
>>       platform_set_drvdata(pdev, host);
>>
>> @@ -631,6 +759,12 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>       clk_put(sc->clk_io);
>>
>>   err_io_clk:
>> +     for (ptr = 0; ptr < NUM_GPIOS(sc->pdata->max_width); ptr++)
>> +             gpio_free(sc->gpios[ptr]);
>> +     if (pdata->cd_type == S3C_SDHCI_CD_INTERNAL)
>> +             gpio_free(sc->ext_cd_gpio);
>> +
>> + err_pdata:
>>       sdhci_free_host(host);
>>
>>       return ret;
>> @@ -638,9 +772,9 @@ static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
>>
>>  static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
>>  {
>> -     struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
>>       struct sdhci_host *host =  platform_get_drvdata(pdev);
>>       struct sdhci_s3c *sc = sdhci_priv(host);
>> +     struct s3c_sdhci_platdata *pdata = sc->pdata;
>>       int ptr;
>>
>>       if (pdata->cd_type == S3C_SDHCI_CD_EXTERNAL && pdata->ext_cd_cleanup)
>> @@ -665,6 +799,11 @@ static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
>>       clk_disable(sc->clk_io);
>>       clk_put(sc->clk_io);
>>
>> +     if (pdev->dev.of_node) {
>> +             for (ptr = 0; ptr < NUM_GPIOS(sc->pdata->max_width); ptr++)
>> +                     gpio_free(sc->gpios[ptr]);
>> +     }
>> +
>>       sdhci_free_host(host);
>>       platform_set_drvdata(pdev, NULL);
>>
>> @@ -737,6 +876,16 @@ 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 = (void *)EXYNOS4_SDHCI_DRV_DATA },
>> +     {},
>> +};
>> +MODULE_DEVICE_TABLE(of, sdhci_s3c_dt_match);
>> +#endif
>> +
>>  static struct platform_driver sdhci_s3c_driver = {
>>       .probe          = sdhci_s3c_probe,
>>       .remove         = __devexit_p(sdhci_s3c_remove),
>> @@ -744,6 +893,7 @@ static struct platform_driver sdhci_s3c_driver = {
>>       .driver         = {
>>               .owner  = THIS_MODULE,
>>               .name   = "s3c-sdhci",
>> +             .of_match_table = of_match_ptr(sdhci_s3c_dt_match),
>>               .pm     = SDHCI_S3C_PMOPS,
>>       },
>>  };
>>
>


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