From f2e2e596a221c146082821aa4d9ae249fe9d561a Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Thu, 20 Sep 2012 22:03:42 +0200 Subject: 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 --- drivers/clk/clk-mux.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100644 drivers/clk/clk-mux.c (limited to 'drivers/clk/clk-mux.c') 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 , 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 +#include +#include +#include +#include + +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; +} -- cgit v1.2.3