On Thu, May 03, 2012 at 03:36:14PM +0530, Viresh Kumar wrote:
> From: Sascha Hauer <s.hauer at 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 at pengutronix.de>
> Reviewed-by: Viresh Kumar <viresh.kumar at st.com>
> Reviewed-by: Mike Turquette <mturquette at 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 at 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
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |