[RFC PATCH 2/3] regmap: Add reg_update_bits() support

[Baolin Wang <baolin.wang7@gmail.com>]

Add reg_update_bits() support in case some platforms use a special method
to update bits of registers.

Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
 drivers/base/regmap/regmap-mmio.c | 29 ++++++++++++++++++++++++++++-
 drivers/base/regmap/regmap.c      |  1 +
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c
index af967d8..dae0d28 100644
--- a/drivers/base/regmap/regmap-mmio.c
+++ b/drivers/base/regmap/regmap-mmio.c
@@ -24,6 +24,8 @@ struct regmap_mmio_context {
 			  unsigned int reg, unsigned int val);
 	unsigned int (*reg_read)(struct regmap_mmio_context *ctx,
 			         unsigned int reg);
+	int (*reg_update_bits)(void *ctx, unsigned int reg,
+			       unsigned int mask, unsigned int val);
 };
 
 static int regmap_mmio_regbits_check(size_t reg_bits)
@@ -188,6 +190,26 @@ static int regmap_mmio_read(void *context, unsigned int reg, unsigned int *val)
 	return 0;
 }
 
+static int regmap_mmio_update_bits(void *context, unsigned int reg,
+				   unsigned int mask, unsigned int val)
+{
+	struct regmap_mmio_context *ctx = context;
+	int ret;
+
+	if (!IS_ERR(ctx->clk)) {
+		ret = clk_enable(ctx->clk);
+		if (ret < 0)
+			return ret;
+	}
+
+	ctx->reg_update_bits(ctx->regs, reg, mask, val);
+
+	if (!IS_ERR(ctx->clk))
+		clk_disable(ctx->clk);
+
+	return 0;
+}
+
 static void regmap_mmio_free_context(void *context)
 {
 	struct regmap_mmio_context *ctx = context;
@@ -200,7 +222,7 @@ static void regmap_mmio_free_context(void *context)
 	kfree(context);
 }
 
-static const struct regmap_bus regmap_mmio = {
+static struct regmap_bus regmap_mmio = {
 	.fast_io = true,
 	.reg_write = regmap_mmio_write,
 	.reg_read = regmap_mmio_read,
@@ -239,6 +261,11 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,
 	ctx->val_bytes = config->val_bits / 8;
 	ctx->clk = ERR_PTR(-ENODEV);
 
+	if (config->reg_update_bits) {
+		ctx->reg_update_bits = config->reg_update_bits;
+		regmap_mmio.reg_update_bits = regmap_mmio_update_bits;
+	}
+
 	switch (regmap_get_val_endian(dev, &regmap_mmio, config)) {
 	case REGMAP_ENDIAN_DEFAULT:
 	case REGMAP_ENDIAN_LITTLE:
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 59f911e..553d92a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -827,6 +827,7 @@ struct regmap *__regmap_init(struct device *dev,
 	} else if (!bus->read || !bus->write) {
 		map->reg_read = _regmap_bus_reg_read;
 		map->reg_write = _regmap_bus_reg_write;
+		map->reg_update_bits = bus->reg_update_bits;
 
 		map->defer_caching = false;
 		goto skip_format_initialization;
-- 
1.9.1