Messages in this thread Patch in this message | | | Subject | Re: [RFC PATCH] regmap: mmio: add register clock support | From | Philipp Zabel <> | Date | Thu, 14 Feb 2013 13:38:43 +0100 |
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Hi Mark,
Am Donnerstag, den 14.02.2013, 11:56 +0000 schrieb Mark Brown: > On Thu, Feb 14, 2013 at 10:49:14AM +0100, Philipp Zabel wrote: > > > 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. > > This is a good feature but a couple of concerns here. > > > + if (ctx->clk) > > + clk_prepare_enable(ctx->clk); > > + > > This is only going to work if prepare doesn't sleep. That's probably > fine for the use cases we're interested in but doesn't fill me with joy.
Good point. I moved clk_prepare/unprepare into regmap_mmio_gen_context/free_context.
> The other thing is that we ought to check the return value.
Done.
Are you ok with the way (devm_)regmap_mmio_init_clk are added? Maybe (devm_)regmap_mmio_init should be turned into inlines.
thanks Philipp
From: Philipp Zabel <p.zabel@pengutronix.de> Subject: [PATCH] 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> --- drivers/base/regmap/regmap-mmio.c | 108 +++++++++++++++++++++++++++++++++++-- include/linux/regmap.h | 6 +++ 2 files changed, 111 insertions(+), 3 deletions(-)
diff --git a/drivers/base/regmap/regmap-mmio.c b/drivers/base/regmap/regmap-mmio.c index f05fc74..8ccac3f 100644 --- a/drivers/base/regmap/regmap-mmio.c +++ b/drivers/base/regmap/regmap-mmio.c @@ -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); @@ -179,7 +210,27 @@ 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); } /** @@ -198,7 +249,7 @@ struct regmap *regmap_init_mmio(struct device *dev, { struct regmap_mmio_context *ctx; - ctx = regmap_mmio_gen_context(regs, config); + ctx = regmap_mmio_gen_context(dev, NULL, regs, config); if (IS_ERR(ctx)) return ERR_CAST(ctx); @@ -207,6 +258,31 @@ struct regmap *regmap_init_mmio(struct device *dev, EXPORT_SYMBOL_GPL(regmap_init_mmio); /** + * 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_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(dev, clk_id, regs, config); + if (IS_ERR(ctx)) + return ERR_CAST(ctx); + + return regmap_init(dev, ®map_mmio, ctx, config); +} +EXPORT_SYMBOL_GPL(regmap_init_mmio_clk); + +/** * devm_regmap_init_mmio(): Initialise managed register map * * @dev: Device that will be interacted with @@ -223,7 +299,7 @@ struct regmap *devm_regmap_init_mmio(struct device *dev, { struct regmap_mmio_context *ctx; - ctx = regmap_mmio_gen_context(regs, config); + ctx = regmap_mmio_gen_context(dev, NULL, regs, config); if (IS_ERR(ctx)) return ERR_CAST(ctx); @@ -231,4 +307,30 @@ struct regmap *devm_regmap_init_mmio(struct device *dev, } EXPORT_SYMBOL_GPL(devm_regmap_init_mmio); +/** + * 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_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(dev, clk_id, regs, config); + if (IS_ERR(ctx)) + return ERR_CAST(ctx); + + return devm_regmap_init(dev, ®map_mmio, ctx, config); +} +EXPORT_SYMBOL_GPL(devm_regmap_init_mmio_clk); + MODULE_LICENSE("GPL v2"); diff --git a/include/linux/regmap.h b/include/linux/regmap.h index b7e95bf..5850848 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -288,6 +288,9 @@ struct regmap *regmap_init_spi(struct spi_device *dev, 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, @@ -300,6 +303,9 @@ struct regmap *devm_regmap_init_spi(struct spi_device *dev, 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); void regmap_exit(struct regmap *map); int regmap_reinit_cache(struct regmap *map, -- 1.7.10.4
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