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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>
hifive-unleashed-5.1
Philipp Zabel 2013-02-14 17:39:08 +01:00 committed by Mark Brown
parent 836dc9e3fb
commit 878ec67b3a
2 changed files with 107 additions and 19 deletions
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79
drivers/base/regmap/regmap-mmio.c
View File

@ -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,
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_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,
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)
{
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");

47
include/linux/regmap.h
View File

@ -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,