mmc: Add SDIO function devicetree subnode parsing

This adds SDIO devicetree subnode parsing to the mmc core. While
SDIO devices are runtime probable they sometimes need nonprobable
additional information on embedded systems, like an additional gpio
interrupt or a clock. This patch makes it possible to supply this
information from the devicetree. SDIO drivers will find a pointer
to the devicenode in their devices of_node pointer.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[hdegoede@redhat.com: Misc. cleanups]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/bus.c

@@ -16,6 +16,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/stat.h>
+#include <linux/of.h>
 #include <linux/pm_runtime.h>
 
 #include <linux/mmc/card.h>
@@ -321,6 +322,8 @@ int mmc_add_card(struct mmc_card *card)
 #endif
 	mmc_init_context_info(card->host);
 
+	card->dev.of_node = mmc_of_find_child_device(card->host, 0);
+
 	ret = device_add(&card->dev);
 	if (ret)
 		return ret;
@@ -349,6 +352,7 @@ void mmc_remove_card(struct mmc_card *card)
 				mmc_hostname(card->host), card->rca);
 		}
 		device_del(&card->dev);
+		of_node_put(card->dev.of_node);
 	}
 
 	put_device(&card->dev);

drivers/mmc/core/core.c

@@ -1232,6 +1232,34 @@ EXPORT_SYMBOL(mmc_of_parse_voltage);
 
 #endif /* CONFIG_OF */
 
+static int mmc_of_get_func_num(struct device_node *node)
+{
+	u32 reg;
+	int ret;
+
+	ret = of_property_read_u32(node, "reg", &reg);
+	if (ret < 0)
+		return ret;
+
+	return reg;
+}
+
+struct device_node *mmc_of_find_child_device(struct mmc_host *host,
+		unsigned func_num)
+{
+	struct device_node *node;
+
+	if (!host->parent || !host->parent->of_node)
+		return NULL;
+
+	for_each_child_of_node(host->parent->of_node, node) {
+		if (mmc_of_get_func_num(node) == func_num)
+			return node;
+	}
+
+	return NULL;
+}
+
 #ifdef CONFIG_REGULATOR
 
 /**

drivers/mmc/core/core.h

@@ -32,6 +32,9 @@ struct mmc_bus_ops {
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
 void mmc_detach_bus(struct mmc_host *host);
 
+struct device_node *mmc_of_find_child_device(struct mmc_host *host,
+		unsigned func_num);
+
 void mmc_init_erase(struct mmc_card *card);
 
 void mmc_set_chip_select(struct mmc_host *host, int mode);

drivers/mmc/core/sdio_bus.c

@@ -22,7 +22,9 @@
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/sdio_func.h>
+#include <linux/of.h>
 
+#include "core.h"
 #include "sdio_cis.h"
 #include "sdio_bus.h"
 
@@ -295,6 +297,13 @@ static void sdio_acpi_set_handle(struct sdio_func *func)
 static inline void sdio_acpi_set_handle(struct sdio_func *func) {}
 #endif
 
+static void sdio_set_of_node(struct sdio_func *func)
+{
+	struct mmc_host *host = func->card->host;
+
+	func->dev.of_node = mmc_of_find_child_device(host, func->num);
+}
+
 /*
  * Register a new SDIO function with the driver model.
  */
@@ -304,6 +313,7 @@ int sdio_add_func(struct sdio_func *func)
 
 	dev_set_name(&func->dev, "%s:%d", mmc_card_id(func->card), func->num);
 
+	sdio_set_of_node(func);
 	sdio_acpi_set_handle(func);
 	ret = device_add(&func->dev);
 	if (ret == 0) {
@@ -327,6 +337,7 @@ void sdio_remove_func(struct sdio_func *func)
 
 	dev_pm_domain_detach(&func->dev, false);
 	device_del(&func->dev);
+	of_node_put(func->dev.of_node);
 	put_device(&func->dev);
 }