mmc: dw_mmc: add device tree support

Add device tree based discovery support.

Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

3 files changed, 211 insertions, 7 deletions

diff --git a/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
new file mode 100644
index 000000000000..06cd32d08052
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/synposis-dw-mshc.txt
@@ -0,0 +1,79 @@
+* Synopsis Designware Mobile Storage Host Controller
+
+The Synopsis designware mobile storage host controller is used to interface
+a SoC with storage medium such as eMMC or SD/MMC cards. This file documents
+differences between the core mmc properties described by mmc.txt and the
+properties used by the Synopsis Designware Mobile Storage Host Controller.
+
+Required Properties:
+
+* compatible: should be
+        - snps,dw-mshc: for controllers compliant with synopsis dw-mshc.
+* #address-cells: should be 1.
+* #size-cells: should be 0.
+
+# Slots: The slot specific information are contained within child-nodes with
+  each child-node representing a supported slot. There should be atleast one
+  child node representing a card slot. The name of the child node representing
+  the slot is recommended to be slot@n where n is the unique number of the slot
+  connnected to the controller. The following are optional properties which
+  can be included in the slot child node.
+
+        * reg: specifies the physical slot number. The valid values of this
+          property is 0 to (num-slots -1), where num-slots is the value
+          specified by the num-slots property.
+
+        * bus-width: as documented in mmc core bindings.
+
+        * wp-gpios: specifies the write protect gpio line. The format of the
+          gpio specifier depends on the gpio controller. If the write-protect
+          line is not available, this property is optional.
+
+Optional properties:
+
+* num-slots: specifies the number of slots supported by the controller.
+  The number of physical slots actually used could be equal or less than the
+  value specified by num-slots. If this property is not specified, the value
+  of num-slot property is assumed to be 1.
+
+* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
+  specified, the default value of the fifo size is determined from the
+  controller registers.
+
+* card-detect-delay: Delay in milli-seconds before detecting card after card
+  insert event. The default value is 0.
+
+* supports-highspeed: Enables support for high speed cards (upto 50MHz)
+
+* broken-cd: as documented in mmc core bindings.
+
+Aliases:
+
+- All the MSHC controller nodes should be represented in the aliases node using
+  the following format 'mshc{n}' where n is a unique number for the alias.
+
+Example:
+
+The MSHC controller node can be split into two portions, SoC specific and
+board specific portions as listed below.
+
+        dwmmc0@12200000 {
+                compatible = "snps,dw-mshc";
+                reg = <0x12200000 0x1000>;
+                interrupts = <0 75 0>;
+                #address-cells = <1>;
+                #size-cells = <0>;
+        };
+
+        dwmmc0@12200000 {
+                num-slots = <1>;
+                supports-highspeed;
+                broken-cd;
+                fifo-depth = <0x80>;
+                card-detect-delay = <200>;
+
+                slot@0 {
+                        reg = <0>;
+                        bus-width = <8>;
+                };
+        };
diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
index ce7be1ac6621..72059050540f 100644
--- a/drivers/mmc/host/dw_mmc-pltfm.c
+++ b/drivers/mmc/host/dw_mmc-pltfm.c
@@ -19,6 +19,8 @@
 #include <linux/mmc/host.h>
 #include <linux/mmc/mmc.h>
 #include <linux/mmc/dw_mmc.h>
+#include <linux/of.h>
+
 #include "dw_mmc.h"
 
 static int __devinit dw_mci_pltfm_probe(struct platform_device *pdev)
@@ -94,10 +96,17 @@ static int dw_mci_pltfm_resume(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(dw_mci_pltfm_pmops, dw_mci_pltfm_suspend, dw_mci_pltfm_resume);
 
+static const struct of_device_id dw_mci_pltfm_match[] = {
+        { .compatible = "snps,dw-mshc", },
+        {},
+};
+MODULE_DEVICE_TABLE(of, dw_mci_pltfm_match);
+
 static struct platform_driver dw_mci_pltfm_driver = {
         .remove         = __exit_p(dw_mci_pltfm_remove),
         .driver         = {
                 .name           = "dw_mmc",
+                .of_match_table = of_match_ptr(dw_mci_pltfm_match),
                 .pm             = &dw_mci_pltfm_pmops,
         },
 };
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 455a155406bc..c792466fb8ac 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -33,6 +33,7 @@
 #include <linux/bitops.h>
 #include <linux/regulator/consumer.h>
 #include <linux/workqueue.h>
+#include <linux/of.h>
 
 #include "dw_mmc.h"
 
@@ -1769,10 +1770,57 @@ static void dw_mci_work_routine_card(struct work_struct *work)
         }
 }
 
+#ifdef CONFIG_OF
+/* given a slot id, find out the device node representing that slot */
+static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
+{
+        struct device_node *np;
+        const __be32 *addr;
+        int len;
+
+        if (!dev || !dev->of_node)
+                return NULL;
+
+        for_each_child_of_node(dev->of_node, np) {
+                addr = of_get_property(np, "reg", &len);
+                if (!addr || (len < sizeof(int)))
+                        continue;
+                if (be32_to_cpup(addr) == slot)
+                        return np;
+        }
+        return NULL;
+}
+
+/* find out bus-width for a given slot */
+static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
+{
+        struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
+        u32 bus_wd = 1;
+
+        if (!np)
+                return 1;
+
+        if (of_property_read_u32(np, "bus-width", &bus_wd))
+                dev_err(dev, "bus-width property not found, assuming width"
+                               " as 1\n");
+        return bus_wd;
+}
+#else /* CONFIG_OF */
+static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
+{
+        return 1;
+}
+static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
+{
+        return NULL;
+}
+#endif /* CONFIG_OF */
+
 static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
 {
         struct mmc_host *mmc;
         struct dw_mci_slot *slot;
+        u8 bus_width;
 
         mmc = mmc_alloc_host(sizeof(struct dw_mci_slot), host->dev);
         if (!mmc)
@@ -1782,6 +1830,7 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
         slot->id = id;
         slot->mmc = mmc;
         slot->host = host;
+        host->slot[id] = slot;
 
         mmc->ops = &dw_mci_ops;
         mmc->f_min = DIV_ROUND_UP(host->bus_hz, 510);
@@ -1806,8 +1855,18 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
                 mmc->caps2 = host->pdata->caps2;
 
         if (host->pdata->get_bus_wd)
-                if (host->pdata->get_bus_wd(slot->id) >= 4)
-                        mmc->caps |= MMC_CAP_4_BIT_DATA;
+                bus_width = host->pdata->get_bus_wd(slot->id);
+        else if (host->dev->of_node)
+                bus_width = dw_mci_of_get_bus_wd(host->dev, slot->id);
+        else
+                bus_width = 1;
+
+        switch (bus_width) {
+        case 8:
+                mmc->caps |= MMC_CAP_8_BIT_DATA;
+        case 4:
+                mmc->caps |= MMC_CAP_4_BIT_DATA;
+        }
 
         if (host->pdata->quirks & DW_MCI_QUIRK_HIGHSPEED)
                 mmc->caps |= MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED;
@@ -1852,7 +1911,6 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
         else
                 clear_bit(DW_MMC_CARD_PRESENT, &slot->flags);
 
-        host->slot[id] = slot;
         mmc_add_host(mmc);
 
 #if defined(CONFIG_DEBUG_FS)
@@ -1944,16 +2002,74 @@ static bool mci_wait_reset(struct device *dev, struct dw_mci *host)
         return false;
 }
 
+#ifdef CONFIG_OF
+static struct dw_mci_of_quirks {
+        char *quirk;
+        int id;
+} of_quirks[] = {
+        {
+                .quirk  = "supports-highspeed",
+                .id     = DW_MCI_QUIRK_HIGHSPEED,
+        }, {
+                .quirk  = "broken-cd",
+                .id     = DW_MCI_QUIRK_BROKEN_CARD_DETECTION,
+        },
+};
+
+static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
+{
+        struct dw_mci_board *pdata;
+        struct device *dev = host->dev;
+        struct device_node *np = dev->of_node;
+        int idx;
+
+        pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+        if (!pdata) {
+                dev_err(dev, "could not allocate memory for pdata\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        /* find out number of slots supported */
+        if (of_property_read_u32(dev->of_node, "num-slots",
+                                &pdata->num_slots)) {
+                dev_info(dev, "num-slots property not found, "
+                                "assuming 1 slot is available\n");
+                pdata->num_slots = 1;
+        }
+
+        /* get quirks */
+        for (idx = 0; idx < ARRAY_SIZE(of_quirks); idx++)
+                if (of_get_property(np, of_quirks[idx].quirk, NULL))
+                        pdata->quirks |= of_quirks[idx].id;
+
+        if (of_property_read_u32(np, "fifo-depth", &pdata->fifo_depth))
+                dev_info(dev, "fifo-depth property not found, using "
+                                "value of FIFOTH register as default\n");
+
+        of_property_read_u32(np, "card-detect-delay", &pdata->detect_delay_ms);
+
+        return pdata;
+}
+
+#else /* CONFIG_OF */
+static struct dw_mci_board *dw_mci_parse_dt(struct dw_mci *host)
+{
+        return ERR_PTR(-EINVAL);
+}
+#endif /* CONFIG_OF */
+
 int dw_mci_probe(struct dw_mci *host)
 {
         int width, i, ret = 0;
         u32 fifo_size;
         int init_slots = 0;
 
-        if (!host->pdata || !host->pdata->init) {
-                dev_err(host->dev,
-                        "Platform data must supply init function\n");
-                return -ENODEV;
+        if (!host->pdata) {
+                host->pdata = dw_mci_parse_dt(host);
+                if (IS_ERR(host->pdata)) {
+                        dev_err(host->dev, "platform data not available\n");
+                        return -EINVAL;
+                }
         }
 
         if (!host->pdata->select_slot && host->pdata->num_slots > 1) {