Skip to content

Commit

Permalink
regmap: mmio: add register clock support
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Philipp Zabel authored and Mark Brown committed Feb 14, 2013
1 parent 836dc9e commit 878ec67
Show file tree
Hide file tree
Showing 2 changed files with 107 additions and 19 deletions.
79 changes: 66 additions & 13 deletions drivers/base/regmap/regmap-mmio.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -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,
Expand All @@ -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) {
Expand Down Expand Up @@ -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;
}

Expand All @@ -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) {
Expand Down Expand Up @@ -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);
}

Expand All @@ -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);
Expand Down Expand Up @@ -179,56 +210,78 @@ 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
*
* 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.
*/
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 changes: 41 additions & 6 deletions include/linux/regmap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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,
Expand All @@ -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,
Expand Down

0 comments on commit 878ec67

Please sign in to comment.