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author | Sascha Hauer <s.hauer@pengutronix.de> | 2012-09-20 22:03:42 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2012-10-04 15:19:55 +0200 |
commit | f2e2e596a221c146082821aa4d9ae249fe9d561a (patch) | |
tree | 2f267a4ad613fcc06bd6a02235c364a4dc2c15e3 /drivers/clk/clk-mux.c | |
parent | 89b710e5094fb5721b18c6501a7c813df9f40b14 (diff) | |
download | barebox-f2e2e596a221c146082821aa4d9ae249fe9d561a.tar.gz barebox-f2e2e596a221c146082821aa4d9ae249fe9d561a.tar.xz |
clk: initial common clk support
This adds barebox common clk support loosely based on the Kernel common
clk support. differences are:
- barebox does not need prepare/unprepare
- no parent rate propagation for set_rate
- struct clk is not really encapsulated from the drivers
Along with the clk support we have support for some basic clk building
blocks:
- clk-fixed
- clk-fixed-factor
- clk-mux
- clk-divider
clk-fixed and clk-fixed-factor are completely generic, clk-mux and clk-divider
are currently the way i.MX muxes/dividers are implemented.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/clk/clk-mux.c')
-rw-r--r-- | drivers/clk/clk-mux.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c new file mode 100644 index 0000000000..cb5f1a1a7b --- /dev/null +++ b/drivers/clk/clk-mux.c @@ -0,0 +1,77 @@ +/* + * clk-mux.c - generic barebox clock support. Based on Linux clk support + * + * Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix + * + * 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 <common.h> +#include <io.h> +#include <malloc.h> +#include <linux/clk.h> +#include <linux/err.h> + +struct clk_mux { + struct clk clk; + void __iomem *reg; + int shift; + int width; +}; + +static int clk_mux_get_parent(struct clk *clk) +{ + struct clk_mux *m = container_of(clk, struct clk_mux, clk); + int idx = readl(m->reg) >> m->shift & ((1 << m->width) - 1); + + return idx; +} + +static int clk_mux_set_parent(struct clk *clk, u8 idx) +{ + struct clk_mux *m = container_of(clk, struct clk_mux, clk); + u32 val; + + val = readl(m->reg); + val &= ~(((1 << m->width) - 1) << m->shift); + val |= idx << m->shift; + writel(val, m->reg); + + return 0; +} + +struct clk_ops clk_mux_ops = { + .get_parent = clk_mux_get_parent, + .set_parent = clk_mux_set_parent, +}; + +struct clk *clk_mux(const char *name, void __iomem *reg, + u8 shift, u8 width, const char **parents, u8 num_parents) +{ + struct clk_mux *m = xzalloc(sizeof(*m)); + int ret; + + m->reg = reg; + m->shift = shift; + m->width = width; + m->clk.ops = &clk_mux_ops; + m->clk.name = name; + m->clk.parent_names = parents; + m->clk.num_parents = num_parents; + + ret = clk_register(&m->clk); + if (ret) { + free(m); + return ERR_PTR(ret); + } + + return &m->clk; +} |