regmap: mmio: add register clock support

Some mmio devices have a dedicated interface clock that needs
to be enabled to access their registers. This patch optionally
enables a clock before accessing registers in the regmap_bus
callbacks.

I added (devm_)regmap_init_mmio_clk variants of the init
functions that have an added clk_id string parameter. This
is passed to clk_get to request the clock from the clk
framework.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 41 insertions, 6 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf942c9..f0480a3297e4 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -285,9 +285,9 @@ struct regmap *regmap_init_i2c(struct i2c_client *i2c,
                                const struct regmap_config *config);
 struct regmap *regmap_init_spi(struct spi_device *dev,
                                const struct regmap_config *config);
-struct regmap *regmap_init_mmio(struct device *dev,
-                                void __iomem *regs,
-                                const struct regmap_config *config);
+struct regmap *regmap_init_mmio_clk(struct device *dev, const char *clk_id,
+                                    void __iomem *regs,
+                                    const struct regmap_config *config);
 
 struct regmap *devm_regmap_init(struct device *dev,
                                 const struct regmap_bus *bus,
@@ -297,9 +297,44 @@ struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
                                     const struct regmap_config *config);
 struct regmap *devm_regmap_init_spi(struct spi_device *dev,
                                     const struct regmap_config *config);
-struct regmap *devm_regmap_init_mmio(struct device *dev,
-                                     void __iomem *regs,
-                                     const struct regmap_config *config);
+struct regmap *devm_regmap_init_mmio_clk(struct device *dev, const char *clk_id,
+                                         void __iomem *regs,
+                                         const struct regmap_config *config);
+
+/**
+ * regmap_init_mmio(): Initialise register map
+ *
+ * @dev: Device that will be interacted with
+ * @regs: Pointer to memory-mapped IO region
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer to
+ * a struct regmap.
+ */
+static inline struct regmap *regmap_init_mmio(struct device *dev,
+                                        void __iomem *regs,
+                                        const struct regmap_config *config)
+{
+        return regmap_init_mmio_clk(dev, NULL, regs, config);
+}
+
+/**
+ * devm_regmap_init_mmio(): Initialise managed register map
+ *
+ * @dev: Device that will be interacted with
+ * @regs: Pointer to memory-mapped IO region
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap.  The regmap will be automatically freed by the
+ * device management code.
+ */
+static inline struct regmap *devm_regmap_init_mmio(struct device *dev,
+                                        void __iomem *regs,
+                                        const struct regmap_config *config)
+{
+        return devm_regmap_init_mmio_clk(dev, NULL, regs, config);
+}
 
 void regmap_exit(struct regmap *map);
 int regmap_reinit_cache(struct regmap *map,