X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fclk%2Fshmobile%2Fclk-div6.c;fp=kernel%2Fdrivers%2Fclk%2Fshmobile%2Fclk-div6.c;h=036a692c72195db93760e40dc1fcb1928b1ecded;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git diff --git a/kernel/drivers/clk/shmobile/clk-div6.c b/kernel/drivers/clk/shmobile/clk-div6.c new file mode 100644 index 000000000..036a692c7 --- /dev/null +++ b/kernel/drivers/clk/shmobile/clk-div6.c @@ -0,0 +1,284 @@ +/* + * r8a7790 Common Clock Framework support + * + * Copyright (C) 2013 Renesas Solutions Corp. + * + * Contact: Laurent Pinchart + * + * 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 +#include +#include +#include +#include +#include +#include + +#define CPG_DIV6_CKSTP BIT(8) +#define CPG_DIV6_DIV(d) ((d) & 0x3f) +#define CPG_DIV6_DIV_MASK 0x3f + +/** + * struct div6_clock - CPG 6 bit divider 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; + u32 src_shift; + u32 src_width; + u8 *parents; +}; + +#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); + u32 val; + + val = (clk_readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP)) + | CPG_DIV6_DIV(clock->div - 1); + clk_writel(val, clock->reg); + + return 0; +} + +static void cpg_div6_clock_disable(struct clk_hw *hw) +{ + struct div6_clock *clock = to_div6_clock(hw); + u32 val; + + val = clk_readl(clock->reg); + val |= CPG_DIV6_CKSTP; + /* + * DIV6 clocks require the divisor field to be non-zero when stopping + * the clock. However, some clocks (e.g. ZB on sh73a0) fail to be + * re-enabled later if the divisor field is changed when stopping the + * clock + */ + if (!(val & CPG_DIV6_DIV_MASK)) + val |= CPG_DIV6_DIV_MASK; + clk_writel(val, 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; + + if (!rate) + rate = 1; + + 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); + u32 val; + + clock->div = div; + + val = clk_readl(clock->reg) & ~CPG_DIV6_DIV_MASK; + /* Only program the new divisor if the clock isn't stopped. */ + if (!(val & CPG_DIV6_CKSTP)) + clk_writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg); + + return 0; +} + +static u8 cpg_div6_clock_get_parent(struct clk_hw *hw) +{ + struct div6_clock *clock = to_div6_clock(hw); + unsigned int i; + u8 hw_index; + + if (clock->src_width == 0) + return 0; + + hw_index = (clk_readl(clock->reg) >> clock->src_shift) & + (BIT(clock->src_width) - 1); + for (i = 0; i < __clk_get_num_parents(hw->clk); i++) { + if (clock->parents[i] == hw_index) + return i; + } + + pr_err("%s: %s DIV6 clock set to invalid parent %u\n", + __func__, __clk_get_name(hw->clk), hw_index); + return 0; +} + +static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index) +{ + struct div6_clock *clock = to_div6_clock(hw); + u8 hw_index; + u32 mask; + + if (index >= __clk_get_num_parents(hw->clk)) + return -EINVAL; + + mask = ~((BIT(clock->src_width) - 1) << clock->src_shift); + hw_index = clock->parents[index]; + + clk_writel((clk_readl(clock->reg) & mask) | + (hw_index << clock->src_shift), 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, + .get_parent = cpg_div6_clock_get_parent, + .set_parent = cpg_div6_clock_set_parent, + .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) +{ + unsigned int num_parents, valid_parents; + const char **parent_names; + struct clk_init_data init; + struct div6_clock *clock; + const char *name; + struct clk *clk; + unsigned int i; + int ret; + + clock = kzalloc(sizeof(*clock), GFP_KERNEL); + if (!clock) + return; + + num_parents = of_clk_get_parent_count(np); + if (num_parents < 1) { + pr_err("%s: no parent found for %s DIV6 clock\n", + __func__, np->name); + return; + } + + clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents), + GFP_KERNEL); + parent_names = kmalloc_array(num_parents, sizeof(*parent_names), + GFP_KERNEL); + if (!parent_names) + 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; + } + + + for (i = 0, valid_parents = 0; i < num_parents; i++) { + const char *name = of_clk_get_parent_name(np, i); + + if (name) { + parent_names[valid_parents] = name; + clock->parents[valid_parents] = i; + valid_parents++; + } + } + + switch (num_parents) { + case 1: + /* fixed parent clock */ + clock->src_shift = clock->src_width = 0; + break; + case 4: + /* clock with EXSRC bits 6-7 */ + clock->src_shift = 6; + clock->src_width = 2; + break; + case 8: + /* VCLK with EXSRC bits 12-14 */ + clock->src_shift = 12; + clock->src_width = 3; + break; + default: + pr_err("%s: invalid number of parents for DIV6 clock %s\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_names; + init.num_parents = valid_parents; + + 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); + + kfree(parent_names); + return; + +error: + if (clock->reg) + iounmap(clock->reg); + kfree(parent_names); + kfree(clock); +} +CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);