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Commit 878ec67b authored by Philipp Zabel's avatar Philipp Zabel Committed by Mark Brown
Browse files

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: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 836dc9e3

drivers/base/regmap/regmap-mmio.c

+66 −13
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */



#include <linux/clk.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/io.h>
@@ -26,6 +27,7 @@ 
struct regmap_mmio_context {

	void __iomem *regs;

	unsigned val_bytes;

	struct clk *clk;

};



static int regmap_mmio_gather_write(void *context,
@@ -34,9 +36,16 @@ static int regmap_mmio_gather_write(void *context, 
{

	struct regmap_mmio_context *ctx = context;

	u32 offset;

	int ret;



	BUG_ON(reg_size != 4);



	if (ctx->clk) {

		ret = clk_enable(ctx->clk);

		if (ret < 0)

			return ret;

	}



	offset = *(u32 *)reg;



	while (val_size) {
@@ -64,6 +73,9 @@ static int regmap_mmio_gather_write(void *context, 
		offset += ctx->val_bytes;

	}



	if (ctx->clk)

		clk_disable(ctx->clk);



	return 0;

}
@@ -80,9 +92,16 @@ static int regmap_mmio_read(void *context, 
{

	struct regmap_mmio_context *ctx = context;

	u32 offset;

	int ret;



	BUG_ON(reg_size != 4);



	if (ctx->clk) {

		ret = clk_enable(ctx->clk);

		if (ret < 0)

			return ret;

	}



	offset = *(u32 *)reg;



	while (val_size) {
@@ -110,11 +129,20 @@ static int regmap_mmio_read(void *context, 
		offset += ctx->val_bytes;

	}



	if (ctx->clk)

		clk_disable(ctx->clk);



	return 0;

}



static void regmap_mmio_free_context(void *context)

{

	struct regmap_mmio_context *ctx = context;



	if (ctx->clk) {

		clk_unprepare(ctx->clk);

		clk_put(ctx->clk);

	}

	kfree(context);

}
@@ -128,11 +156,14 @@ static struct regmap_bus regmap_mmio = { 
	.val_format_endian_default = REGMAP_ENDIAN_NATIVE,

};



static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs,

static struct regmap_mmio_context *regmap_mmio_gen_context(struct device *dev,

					const char *clk_id,

					void __iomem *regs,

					const struct regmap_config *config)

{

	struct regmap_mmio_context *ctx;

	int min_stride;

	int ret;



	if (config->reg_bits != 32)

		return ERR_PTR(-EINVAL);
@@ -179,37 +210,59 @@ static struct regmap_mmio_context *regmap_mmio_gen_context(void __iomem *regs, 
	ctx->regs = regs;

	ctx->val_bytes = config->val_bits / 8;



	if (clk_id == NULL)

		return ctx;



	ctx->clk = clk_get(dev, clk_id);

	if (IS_ERR(ctx->clk)) {

		ret = PTR_ERR(ctx->clk);

		goto err_free;

	}



	ret = clk_prepare(ctx->clk);

	if (ret < 0) {

		clk_put(ctx->clk);

		goto err_free;

	}



	return ctx;



err_free:

	kfree(ctx);



	return ERR_PTR(ret);

}



/**

 * regmap_init_mmio(): Initialise register map

 * regmap_init_mmio_clk(): Initialise register map with register clock

 *

 * @dev: Device that will be interacted with

 * @clk_id: register clock consumer ID

 * @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.

 */

struct regmap *regmap_init_mmio(struct device *dev,

struct regmap *regmap_init_mmio_clk(struct device *dev, const char *clk_id,

				    void __iomem *regs,

				    const struct regmap_config *config)

{

	struct regmap_mmio_context *ctx;



	ctx = regmap_mmio_gen_context(regs, config);

	ctx = regmap_mmio_gen_context(dev, clk_id, regs, config);

	if (IS_ERR(ctx))

		return ERR_CAST(ctx);



	return regmap_init(dev, &regmap_mmio, ctx, config);

}

EXPORT_SYMBOL_GPL(regmap_init_mmio);

EXPORT_SYMBOL_GPL(regmap_init_mmio_clk);



/**

 * devm_regmap_init_mmio(): Initialise managed register map

 * devm_regmap_init_mmio_clk(): Initialise managed register map with clock

 *

 * @dev: Device that will be interacted with

 * @clk_id: register clock consumer ID

 * @regs: Pointer to memory-mapped IO region

 * @config: Configuration for register map

 *
@@ -217,18 +270,18 @@ EXPORT_SYMBOL_GPL(regmap_init_mmio); 
 * to a struct regmap.  The regmap will be automatically freed by the

 * device management code.

 */

struct regmap *devm_regmap_init_mmio(struct device *dev,

struct regmap *devm_regmap_init_mmio_clk(struct device *dev, const char *clk_id,

					 void __iomem *regs,

					 const struct regmap_config *config)

{

	struct regmap_mmio_context *ctx;



	ctx = regmap_mmio_gen_context(regs, config);

	ctx = regmap_mmio_gen_context(dev, clk_id, regs, config);

	if (IS_ERR(ctx))

		return ERR_CAST(ctx);



	return devm_regmap_init(dev, &regmap_mmio, ctx, config);

}

EXPORT_SYMBOL_GPL(devm_regmap_init_mmio);

EXPORT_SYMBOL_GPL(devm_regmap_init_mmio_clk);



MODULE_LICENSE("GPL v2");

include/linux/regmap.h

+41 −6
Original line number Diff line number Diff line
@@ -285,7 +285,7 @@ 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,

struct regmap *regmap_init_mmio_clk(struct device *dev, const char *clk_id,

				    void __iomem *regs,

				    const struct regmap_config *config);
@@ -297,10 +297,45 @@ 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,

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,

			const struct regmap_config *config);