mmc: mvsdio: implement a Device Tree binding

This patch adds a simple Device Tree binding for the mvsdio driver, as
well as the necessary documentation for it. Compatibility with non-DT
platforms is preserved, by keeping the platform_data based
initialization.

We introduce a small difference between non-DT and DT platforms: DT
platforms are required to provide a clocks = <...> property, which the
driver uses to get the frequency of the clock that goes to the SDIO
IP. The behaviour on non-DT platforms is kept unchanged: a clock
reference is not mandatory, but the clock frequency must be passed in
the "clock" field of the mvsdio_platform_data structure.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Stefan Peter <s.peter@mpl.ch>
Tested-by: Florian Fainelli <florian@openwrt.org>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 66 insertions, 15 deletions

diff --git a/Documentation/devicetree/bindings/mmc/orion-sdio.txt b/Documentation/devicetree/bindings/mmc/orion-sdio.txt
new file mode 100644
index 000000000000..84f0ebd67a13
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/orion-sdio.txt
@@ -0,0 +1,17 @@
+* Marvell orion-sdio controller
+
+This file documents differences between the core properties in mmc.txt
+and the properties used by the orion-sdio driver.
+
+- compatible: Should be "marvell,orion-sdio"
+- clocks: reference to the clock of the SDIO interface
+
+Example:
+
+        mvsdio@d00d4000 {
+                compatible = "marvell,orion-sdio";
+                reg = <0xd00d4000 0x200>;
+                interrupts = <54>;
+                clocks = <&gateclk 17>;
+                status = "disabled";
+        };
diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
index 704b7a3fe873..78d3abf837c2 100644
--- a/drivers/mmc/host/mvsdio.c
+++ b/drivers/mmc/host/mvsdio.c
@@ -21,6 +21,8 @@
 #include <linux/irq.h>
 #include <linux/clk.h>
 #include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_irq.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/slot-gpio.h>
 
@@ -681,17 +683,17 @@ mv_conf_mbus_windows(struct mvsd_host *host,
 
 static int __init mvsd_probe(struct platform_device *pdev)
 {
+        struct device_node *np = pdev->dev.of_node;
         struct mmc_host *mmc = NULL;
         struct mvsd_host *host = NULL;
-        const struct mvsdio_platform_data *mvsd_data;
         const struct mbus_dram_target_info *dram;
         struct resource *r;
         int ret, irq;
+        int gpio_card_detect, gpio_write_protect;
 
         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         irq = platform_get_irq(pdev, 0);
-        mvsd_data = pdev->dev.platform_data;
-        if (!r || irq < 0 || !mvsd_data)
+        if (!r || irq < 0)
                 return -ENXIO;
 
         mmc = mmc_alloc_host(sizeof(struct mvsd_host), &pdev->dev);
@@ -703,8 +705,39 @@ static int __init mvsd_probe(struct platform_device *pdev)
         host = mmc_priv(mmc);
         host->mmc = mmc;
         host->dev = &pdev->dev;
-        host->base_clock = mvsd_data->clock / 2;
-        host->clk = ERR_PTR(-EINVAL);
+
+        /*
+         * Some non-DT platforms do not pass a clock, and the clock
+         * frequency is passed through platform_data. On DT platforms,
+         * a clock must always be passed, even if there is no gatable
+         * clock associated to the SDIO interface (it can simply be a
+         * fixed rate clock).
+         */
+        host->clk = devm_clk_get(&pdev->dev, NULL);
+        if (!IS_ERR(host->clk))
+                clk_prepare_enable(host->clk);
+
+        if (np) {
+                if (IS_ERR(host->clk)) {
+                        dev_err(&pdev->dev, "DT platforms must have a clock associated\n");
+                        ret = -EINVAL;
+                        goto out;
+                }
+
+                host->base_clock = clk_get_rate(host->clk) / 2;
+                gpio_card_detect = of_get_named_gpio(np, "cd-gpios", 0);
+                gpio_write_protect = of_get_named_gpio(np, "wp-gpios", 0);
+        } else {
+                const struct mvsdio_platform_data *mvsd_data;
+                mvsd_data = pdev->dev.platform_data;
+                if (!mvsd_data) {
+                        ret = -ENXIO;
+                        goto out;
+                }
+                host->base_clock = mvsd_data->clock / 2;
+                gpio_card_detect = mvsd_data->gpio_card_detect;
+                gpio_write_protect = mvsd_data->gpio_write_protect;
+        }
 
         mmc->ops = &mvsd_ops;
 
@@ -743,20 +776,14 @@ static int __init mvsd_probe(struct platform_device *pdev)
                 goto out;
         }
 
-        /* Not all platforms can gate the clock, so it is not
-           an error if the clock does not exists. */
-        host->clk = devm_clk_get(&pdev->dev, NULL);
-        if (!IS_ERR(host->clk))
-                clk_prepare_enable(host->clk);
-
-        if (gpio_is_valid(mvsd_data->gpio_card_detect)) {
-                ret = mmc_gpio_request_cd(mmc, mvsd_data->gpio_card_detect);
+        if (gpio_is_valid(gpio_card_detect)) {
+                ret = mmc_gpio_request_cd(mmc, gpio_card_detect);
                 if (ret)
                         goto out;
         } else
                 mmc->caps |= MMC_CAP_NEEDS_POLL;
 
-        mmc_gpio_request_ro(mmc, mvsd_data->gpio_write_protect);
+        mmc_gpio_request_ro(mmc, gpio_write_protect);
 
         setup_timer(&host->timer, mvsd_timeout_timer, (unsigned long)host);
         platform_set_drvdata(pdev, mmc);
@@ -768,7 +795,7 @@ static int __init mvsd_probe(struct platform_device *pdev)
                            mmc_hostname(mmc), DRIVER_NAME);
         if (!(mmc->caps & MMC_CAP_NEEDS_POLL))
                 printk("using GPIO %d for card detection\n",
-                       mvsd_data->gpio_card_detect);
+                       gpio_card_detect);
         else
                 printk("lacking card detect (fall back to polling)\n");
         return 0;
@@ -832,12 +859,19 @@ static int mvsd_resume(struct platform_device *dev)
 #define mvsd_resume     NULL
 #endif
 
+static const struct of_device_id mvsdio_dt_ids[] = {
+        { .compatible = "marvell,orion-sdio" },
+        { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mvsdio_dt_ids);
+
 static struct platform_driver mvsd_driver = {
         .remove         = __exit_p(mvsd_remove),
         .suspend        = mvsd_suspend,
         .resume         = mvsd_resume,
         .driver         = {
                 .name   = DRIVER_NAME,
+                .of_match_table = mvsdio_dt_ids,
         },
 };