diff options
author | Chen-Yu Tsai <wens@csie.org> | 2014-09-16 14:04:01 +0400 |
---|---|---|
committer | Maxime Ripard <maxime.ripard@free-electrons.com> | 2014-09-27 11:05:43 +0400 |
commit | 9c8176bfb67f98ed9a521b624dcb6ab7fa254aa7 (patch) | |
tree | 52bf5988af67aa1c7423010c09dbccfe9ab40671 /drivers/clk/sunxi/clk-sun8i-mbus.c | |
parent | 37e1041f04717d726931c8688cbf425071aeb9c1 (diff) | |
download | linux-9c8176bfb67f98ed9a521b624dcb6ab7fa254aa7.tar.xz |
clk: sunxi: Add sun8i MBUS clock support
The MBUS clock on sun8i is slightly different from the old mod0 clocks.
The divider is 3 bits wider, while also needing a divider table for the
higher 4 values, which all set the same divider.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Diffstat (limited to 'drivers/clk/sunxi/clk-sun8i-mbus.c')
-rw-r--r-- | drivers/clk/sunxi/clk-sun8i-mbus.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/clk/sunxi/clk-sun8i-mbus.c b/drivers/clk/sunxi/clk-sun8i-mbus.c new file mode 100644 index 000000000000..8e49b44cee41 --- /dev/null +++ b/drivers/clk/sunxi/clk-sun8i-mbus.c @@ -0,0 +1,78 @@ +/* + * Copyright 2014 Chen-Yu Tsai + * + * Chen-Yu Tsai <wens@csie.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/of_address.h> + +#include "clk-factors.h" + +/** + * sun8i_a23_get_mbus_factors() - calculates m factor for MBUS clocks + * MBUS rate is calculated as follows + * rate = parent_rate / (m + 1); + */ + +static void sun8i_a23_get_mbus_factors(u32 *freq, u32 parent_rate, + u8 *n, u8 *k, u8 *m, u8 *p) +{ + u8 div; + + /* + * These clocks can only divide, so we will never be able to + * achieve frequencies higher than the parent frequency + */ + if (*freq > parent_rate) + *freq = parent_rate; + + div = DIV_ROUND_UP(parent_rate, *freq); + + if (div > 8) + div = 8; + + *freq = parent_rate / div; + + /* we were called to round the frequency, we can now return */ + if (m == NULL) + return; + + *m = div - 1; +} + +static struct clk_factors_config sun8i_a23_mbus_config = { + .mshift = 0, + .mwidth = 3, +}; + +static const struct factors_data sun8i_a23_mbus_data __initconst = { + .enable = 31, + .mux = 24, + .table = &sun8i_a23_mbus_config, + .getter = sun8i_a23_get_mbus_factors, +}; + +static DEFINE_SPINLOCK(sun8i_a23_mbus_lock); + +static void __init sun8i_a23_mbus_setup(struct device_node *node) +{ + struct clk *mbus = sunxi_factors_register(node, &sun8i_a23_mbus_data, + &sun8i_a23_mbus_lock); + + /* The MBUS clocks needs to be always enabled */ + __clk_get(mbus); + clk_prepare_enable(mbus); +} +CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup); |