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 0000000..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@12530000 {
+               compatible = "samsung,exynos4210-sdhci";
+               reg = <0x12530000 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 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 +424,109 @@ 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)
+{
+       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 +541,7 @@ 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 +557,28 @@ 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 +743,12 @@ 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 +756,9 @@ 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 +783,11 @@ 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 +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 },
+       {},
+};
+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 +877,7 @@ 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,
        },
 };
-- 
1.6.6.rc2

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