diff options
Diffstat (limited to 'drivers/clk/shmobile/clk-div6.c')
| -rw-r--r-- | drivers/clk/shmobile/clk-div6.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/drivers/clk/shmobile/clk-div6.c b/drivers/clk/shmobile/clk-div6.c new file mode 100644 index 000000000000..aac4756ec52e --- /dev/null +++ b/drivers/clk/shmobile/clk-div6.c @@ -0,0 +1,185 @@ +/* + * r8a7790 Common Clock Framework support + * + * Copyright (C) 2013 Renesas Solutions Corp. + * + * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com> + * + * 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; version 2 of the License. + */ + +#include <linux/clk-provider.h> +#include <linux/clkdev.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/of_address.h> + +#define CPG_DIV6_CKSTP BIT(8) +#define CPG_DIV6_DIV(d) ((d) & 0x3f) +#define CPG_DIV6_DIV_MASK 0x3f + +/** + * struct div6_clock - MSTP gating clock + * @hw: handle between common and hardware-specific interfaces + * @reg: IO-remapped register + * @div: divisor value (1-64) + */ +struct div6_clock { + struct clk_hw hw; + void __iomem *reg; + unsigned int div; +}; + +#define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw) + +static int cpg_div6_clock_enable(struct clk_hw *hw) +{ + struct div6_clock *clock = to_div6_clock(hw); + + clk_writel(CPG_DIV6_DIV(clock->div - 1), clock->reg); + + return 0; +} + +static void cpg_div6_clock_disable(struct clk_hw *hw) +{ + struct div6_clock *clock = to_div6_clock(hw); + + /* DIV6 clocks require the divisor field to be non-zero when stopping + * the clock. + */ + clk_writel(CPG_DIV6_CKSTP | CPG_DIV6_DIV(CPG_DIV6_DIV_MASK), + clock->reg); +} + +static int cpg_div6_clock_is_enabled(struct clk_hw *hw) +{ + struct div6_clock *clock = to_div6_clock(hw); + + return !(clk_readl(clock->reg) & CPG_DIV6_CKSTP); +} + +static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct div6_clock *clock = to_div6_clock(hw); + unsigned int div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1; + + return parent_rate / div; +} + +static unsigned int cpg_div6_clock_calc_div(unsigned long rate, + unsigned long parent_rate) +{ + unsigned int div; + + div = DIV_ROUND_CLOSEST(parent_rate, rate); + return clamp_t(unsigned int, div, 1, 64); +} + +static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate); + + return *parent_rate / div; +} + +static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct div6_clock *clock = to_div6_clock(hw); + unsigned int div = cpg_div6_clock_calc_div(rate, parent_rate); + + clock->div = div; + + /* Only program the new divisor if the clock isn't stopped. */ + if (!(clk_readl(clock->reg) & CPG_DIV6_CKSTP)) + clk_writel(CPG_DIV6_DIV(clock->div - 1), clock->reg); + + return 0; +} + +static const struct clk_ops cpg_div6_clock_ops = { + .enable = cpg_div6_clock_enable, + .disable = cpg_div6_clock_disable, + .is_enabled = cpg_div6_clock_is_enabled, + .recalc_rate = cpg_div6_clock_recalc_rate, + .round_rate = cpg_div6_clock_round_rate, + .set_rate = cpg_div6_clock_set_rate, +}; + +static void __init cpg_div6_clock_init(struct device_node *np) +{ + struct clk_init_data init; + struct div6_clock *clock; + const char *parent_name; + const char *name; + struct clk *clk; + int ret; + + clock = kzalloc(sizeof(*clock), GFP_KERNEL); + if (!clock) { + pr_err("%s: failed to allocate %s DIV6 clock\n", + __func__, np->name); + return; + } + + /* Remap the clock register and read the divisor. Disabling the + * clock overwrites the divisor, so we need to cache its value for the + * enable operation. + */ + clock->reg = of_iomap(np, 0); + if (clock->reg == NULL) { + pr_err("%s: failed to map %s DIV6 clock register\n", + __func__, np->name); + goto error; + } + + clock->div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1; + + /* Parse the DT properties. */ + ret = of_property_read_string(np, "clock-output-names", &name); + if (ret < 0) { + pr_err("%s: failed to get %s DIV6 clock output name\n", + __func__, np->name); + goto error; + } + + parent_name = of_clk_get_parent_name(np, 0); + if (parent_name == NULL) { + pr_err("%s: failed to get %s DIV6 clock parent name\n", + __func__, np->name); + goto error; + } + + /* Register the clock. */ + init.name = name; + init.ops = &cpg_div6_clock_ops; + init.flags = CLK_IS_BASIC; + init.parent_names = &parent_name; + init.num_parents = 1; + + clock->hw.init = &init; + + clk = clk_register(NULL, &clock->hw); + if (IS_ERR(clk)) { + pr_err("%s: failed to register %s DIV6 clock (%ld)\n", + __func__, np->name, PTR_ERR(clk)); + goto error; + } + + of_clk_add_provider(np, of_clk_src_simple_get, clk); + + return; + +error: + if (clock->reg) + iounmap(clock->reg); + kfree(clock); +} +CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init); |