[PATCH V4] clk: add a fixed factor clock

[PATCH V4] clk: add a fixed factor clock

[Viresh Kumar]

From: Sascha Hauer <s.hauer@pengutronix.de>

Having fixed factors/dividers in hardware is a common pattern, so
add a basic clock type doing this. It basically describes a fixed
factor clock using a nominator and a denominator.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
Reviewed-by: Mike Turquette <mturquette@linaro.org>
---

Hi Mike,

This patch contains all the fixups that i sent separately. It is based on your
latest clk-next branch.

 drivers/clk/Makefile           |    2 +-
 drivers/clk/clk-fixed-factor.c |   97 ++++++++++++++++++++++++++++++++++++++++
 include/linux/clk-private.h    |   20 ++++++++
 include/linux/clk-provider.h   |   23 +++++++++
 4 files changed, 141 insertions(+), 1 deletions(-)
 create mode 100644 drivers/clk/clk-fixed-factor.c

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 1f736bc..24aa714 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -1,4 +1,4 @@
 
 obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
 obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
-				   clk-mux.o clk-divider.o
+				   clk-mux.o clk-divider.o clk-fixed-factor.o
diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
new file mode 100644
index 0000000..0e8782b
--- /dev/null
+++ b/drivers/clk/clk-fixed-factor.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Standard functionality for the common clock API.
+ */
+#include <linux/module.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+/*
+ * DOC: basic fixed multiplier and divider clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is fixed.  clk->rate = parent->rate / div * mult
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+#define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
+
+static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
+
+	return (parent_rate / fix->div) * fix->mult;
+}
+
+static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *prate)
+{
+	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
+
+	if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
+		unsigned long best_parent;
+
+		best_parent = (rate / fix->mult) * fix->div;
+		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
+				best_parent);
+	}
+
+	return (*prate / fix->div) * fix->mult;
+}
+
+static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long parent_rate)
+{
+	return 0;
+}
+
+struct clk_ops clk_fixed_factor_ops = {
+	.round_rate = clk_factor_round_rate,
+	.set_rate = clk_factor_set_rate,
+	.recalc_rate = clk_factor_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
+
+struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div)
+{
+	struct clk_fixed_factor *fix;
+	struct clk_init_data init;
+	struct clk *clk;
+
+	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
+	if (!fix) {
+		pr_err("%s: could not allocate fixed factor clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	/* struct clk_fixed_factor assignments */
+	fix->mult = mult;
+	fix->div = div;
+	fix->hw.init = &init;
+
+	init.name = name;
+	init.ops = &clk_fixed_factor_ops;
+	init.flags = flags;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	clk = clk_register(dev, &fix->hw);
+
+	if (clk)
+		return clk;
+
+	kfree(fix);
+
+	return NULL;
+}
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index b258532..008f389 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -143,6 +143,26 @@ struct clk {
 	DEFINE_CLK(_name, clk_mux_ops, _flags, _parent_names,	\
 			_parents);
 
+#define DEFINE_CLK_FIXED_FACTOR(_name, _parent_name,		\
+				_parent_ptr, _flags,		\
+				_mult, _div)			\
+	static struct clk _name;				\
+	static char *_name##_parent_names[] = {			\
+		_parent_name,					\
+	};							\
+	static struct clk *_name##_parents[] = {		\
+		_parent_ptr,					\
+	};							\
+	static struct clk_fixed_factor _name##_hw = {		\
+		.hw = {						\
+			.clk = &_name,				\
+		},						\
+		.mult = _mult,					\
+		.div = _div,					\
+	};							\
+	DEFINE_CLK(_name, clk_fixed_factor_ops, _flags,		\
+			_name##_parent_names, _parents);
+
 /**
  * __clk_init - initialize the data structures in a struct clk
  * @dev:	device initializing this clk, placeholder for now
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 5db3412..c1c23b9 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -277,6 +277,29 @@ struct clk *clk_register_mux(struct device *dev, const char *name,
 		u8 clk_mux_flags, spinlock_t *lock);
 
 /**
+ * struct clk_fixed_factor - fixed multiplier and divider clock
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @mult:	multiplier
+ * @div:	divider
+ *
+ * Clock with a fixed multiplier and divider. The output frequency is the
+ * parent clock rate divided by div and multiplied by mult.
+ * Implements .recalc_rate, .set_rate and .round_rate
+ */
+
+struct clk_fixed_factor {
+	struct clk_hw	hw;
+	unsigned int	mult;
+	unsigned int	div;
+};
+
+extern struct clk_ops clk_fixed_factor_ops;
+struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
+		const char *parent_name, unsigned long flags,
+		unsigned int mult, unsigned int div);
+
+/**
  * clk_register - allocate a new clock, register it and return an opaque cookie
  * @dev: device that is registering this clock
  * @hw: link to hardware-specific clock data
-- 
1.7.9

[PATCH V4] clk: add a fixed factor clock

[Sascha Hauer]

On Thu, May 03, 2012 at 03:36:14PM +0530, Viresh Kumar wrote:
> From: Sascha Hauer <s.hauer@pengutronix.de>
> 
> Having fixed factors/dividers in hardware is a common pattern, so
> add a basic clock type doing this. It basically describes a fixed
> factor clock using a nominator and a denominator.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> Reviewed-by: Viresh Kumar <viresh.kumar@st.com>
> Reviewed-by: Mike Turquette <mturquette@linaro.org>
> ---
> 
> Hi Mike,
> 
> This patch contains all the fixups that i sent separately. It is based on your
> latest clk-next branch.
> 
>  drivers/clk/Makefile           |    2 +-
>  drivers/clk/clk-fixed-factor.c |   97 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/clk-private.h    |   20 ++++++++
>  include/linux/clk-provider.h   |   23 +++++++++
>  4 files changed, 141 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/clk/clk-fixed-factor.c
> 
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 1f736bc..24aa714 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -1,4 +1,4 @@
>  
>  obj-$(CONFIG_CLKDEV_LOOKUP)	+= clkdev.o
>  obj-$(CONFIG_COMMON_CLK)	+= clk.o clk-fixed-rate.o clk-gate.o \
> -				   clk-mux.o clk-divider.o
> +				   clk-mux.o clk-divider.o clk-fixed-factor.o
> diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
> new file mode 100644
> index 0000000..0e8782b
> --- /dev/null
> +++ b/drivers/clk/clk-fixed-factor.c
> @@ -0,0 +1,97 @@
> +/*
> + * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * Standard functionality for the common clock API.
> + */
> +#include <linux/module.h>
> +#include <linux/clk-provider.h>
> +#include <linux/slab.h>
> +#include <linux/err.h>
> +
> +/*
> + * DOC: basic fixed multiplier and divider clock that cannot gate
> + *
> + * Traits of this clock:
> + * prepare - clk_prepare only ensures that parents are prepared
> + * enable - clk_enable only ensures that parents are enabled
> + * rate - rate is fixed.  clk->rate = parent->rate / div * mult
> + * parent - fixed parent.  No clk_set_parent support
> + */
> +
> +#define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
> +
> +static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
> +		unsigned long parent_rate)
> +{
> +	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
> +
> +	return (parent_rate / fix->div) * fix->mult;
> +}
> +
> +static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
> +				unsigned long *prate)
> +{
> +	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
> +
> +	if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
> +		unsigned long best_parent;
> +
> +		best_parent = (rate / fix->mult) * fix->div;
> +		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
> +				best_parent);
> +	}
> +
> +	return (*prate / fix->div) * fix->mult;
> +}
> +
> +static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
> +				unsigned long parent_rate)
> +{
> +	return 0;
> +}
> +
> +struct clk_ops clk_fixed_factor_ops = {
> +	.round_rate = clk_factor_round_rate,
> +	.set_rate = clk_factor_set_rate,
> +	.recalc_rate = clk_factor_recalc_rate,
> +};
> +EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
> +
> +struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
> +		const char *parent_name, unsigned long flags,
> +		unsigned int mult, unsigned int div)
> +{
> +	struct clk_fixed_factor *fix;
> +	struct clk_init_data init;
> +	struct clk *clk;
> +
> +	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
> +	if (!fix) {
> +		pr_err("%s: could not allocate fixed factor clk\n", __func__);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	/* struct clk_fixed_factor assignments */
> +	fix->mult = mult;
> +	fix->div = div;
> +	fix->hw.init = &init;
> +
> +	init.name = name;
> +	init.ops = &clk_fixed_factor_ops;
> +	init.flags = flags;
> +	init.parent_names = &parent_name;
> +	init.num_parents = 1;
> +
> +	clk = clk_register(dev, &fix->hw);
> +
> +	if (clk)
> +		return clk;

	if (!IS_ERR(clk))
		...

Sascha

-- 
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[PATCH V4] clk: add a fixed factor clock

[Turquette, Mike]

On Thu, May 3, 2012 at 6:41 AM, viresh kumar <viresh.linux@gmail.com> wrote:
>
> On May 3, 2012 5:38 PM, "Sascha Hauer" <s.hauer@pengutronix.de> wrote:
>>
>
>> > + ? ? if (clk)
>> > + ? ? ? ? ? ? return clk;
>>
>> ? ? ? ?if (!IS_ERR(clk))
>
> Oops. @Mike: can you please fix it while applying?

No problem.

Regards,
Mike

[PATCH V4] clk: add a fixed factor clock

[Mike Turquette]

On 20120503-19:11, viresh kumar wrote:
> On May 3, 2012 5:38 PM, "Sascha Hauer" <s.hauer@pengutronix.de> wrote:
> >
> 
> > > +     if (clk)
> > > +             return clk;
> >
> >        if (!IS_ERR(clk))
> 
> Oops. @Mike: can you please fix it while applying?

I've applied the below fix in my local branch.  Let me know if you have
issue with it before I send out my pull request to Arnd.

Thanks,
Mike


diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
index 0e8782b..1f2da01 100644
--- a/drivers/clk/clk-fixed-factor.c
+++ b/drivers/clk/clk-fixed-factor.c
@@ -88,10 +88,8 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
 
 	clk = clk_register(dev, &fix->hw);
 
-	if (clk)
-		return clk;
+	if (IS_ERR(clk))
+		kfree(fix);
 
-	kfree(fix);
-
-	return NULL;
+	return clk;
 }

[PATCH V4] clk: add a fixed factor clock

[Viresh Kumar]

On 5/7/2012 7:12 AM, Mike Turquette wrote:
> I've applied the below fix in my local branch.  Let me know if you have
> issue with it before I send out my pull request to Arnd.
> 
> Thanks,
> Mike
> 
> 
> diff --git a/drivers/clk/clk-fixed-factor.c b/drivers/clk/clk-fixed-factor.c
> index 0e8782b..1f2da01 100644
> --- a/drivers/clk/clk-fixed-factor.c
> +++ b/drivers/clk/clk-fixed-factor.c
> @@ -88,10 +88,8 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
>  
>  	clk = clk_register(dev, &fix->hw);
>  
> -	if (clk)
> -		return clk;
> +	if (IS_ERR(clk))
> +		kfree(fix);
>  
> -	kfree(fix);
> -
> -	return NULL;
> +	return clk;
>  }

No problems. Please send it to Arnd ASAP.

--
viresh