diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/clk/clk-sparx5.c | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/drivers/clk/clk-sparx5.c b/drivers/clk/clk-sparx5.c new file mode 100644 index 000000000..0fad0c1a0 --- /dev/null +++ b/drivers/clk/clk-sparx5.c @@ -0,0 +1,295 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Microchip Sparx5 SoC Clock driver. + * + * Copyright (c) 2019 Microchip Inc. + * + * Author: Lars Povlsen <lars.povlsen@microchip.com> + */ + +#include <linux/io.h> +#include <linux/module.h> +#include <linux/clk-provider.h> +#include <linux/bitfield.h> +#include <linux/of.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <dt-bindings/clock/microchip,sparx5.h> + +#define PLL_DIV GENMASK(7, 0) +#define PLL_PRE_DIV GENMASK(10, 8) +#define PLL_ROT_DIR BIT(11) +#define PLL_ROT_SEL GENMASK(13, 12) +#define PLL_ROT_ENA BIT(14) +#define PLL_CLK_ENA BIT(15) + +#define MAX_SEL 4 +#define MAX_PRE BIT(3) + +static const u8 sel_rates[MAX_SEL] = { 0, 2*8, 2*4, 2*2 }; + +static const char *clk_names[N_CLOCKS] = { + "core", "ddr", "cpu2", "arm2", + "aux1", "aux2", "aux3", "aux4", + "synce", +}; + +struct s5_hw_clk { + struct clk_hw hw; + void __iomem *reg; +}; + +struct s5_clk_data { + void __iomem *base; + struct s5_hw_clk s5_hw[N_CLOCKS]; +}; + +struct s5_pll_conf { + unsigned long freq; + u8 div; + bool rot_ena; + u8 rot_sel; + u8 rot_dir; + u8 pre_div; +}; + +#define to_s5_pll(hw) container_of(hw, struct s5_hw_clk, hw) + +static unsigned long s5_calc_freq(unsigned long parent_rate, + const struct s5_pll_conf *conf) +{ + unsigned long rate = parent_rate / conf->div; + + if (conf->rot_ena) { + int sign = conf->rot_dir ? -1 : 1; + int divt = sel_rates[conf->rot_sel] * (1 + conf->pre_div); + int divb = divt + sign; + + rate = mult_frac(rate, divt, divb); + rate = roundup(rate, 1000); + } + + return rate; +} + +static void s5_search_fractional(unsigned long rate, + unsigned long parent_rate, + int div, + struct s5_pll_conf *conf) +{ + struct s5_pll_conf best; + ulong cur_offset, best_offset = rate; + int d, i, j; + + memset(conf, 0, sizeof(*conf)); + conf->div = div; + conf->rot_ena = 1; /* Fractional rate */ + + for (d = 0; best_offset > 0 && d <= 1 ; d++) { + conf->rot_dir = !!d; + for (i = 0; best_offset > 0 && i < MAX_PRE; i++) { + conf->pre_div = i; + for (j = 1; best_offset > 0 && j < MAX_SEL; j++) { + conf->rot_sel = j; + conf->freq = s5_calc_freq(parent_rate, conf); + cur_offset = abs(rate - conf->freq); + if (cur_offset < best_offset) { + best_offset = cur_offset; + best = *conf; + } + } + } + } + + /* Best match */ + *conf = best; +} + +static unsigned long s5_calc_params(unsigned long rate, + unsigned long parent_rate, + struct s5_pll_conf *conf) +{ + if (parent_rate % rate) { + struct s5_pll_conf alt1, alt2; + int div; + + div = DIV_ROUND_CLOSEST_ULL(parent_rate, rate); + s5_search_fractional(rate, parent_rate, div, &alt1); + + /* Straight match? */ + if (alt1.freq == rate) { + *conf = alt1; + } else { + /* Try without rounding divider */ + div = parent_rate / rate; + if (div != alt1.div) { + s5_search_fractional(rate, parent_rate, div, + &alt2); + /* Select the better match */ + if (abs(rate - alt1.freq) < + abs(rate - alt2.freq)) + *conf = alt1; + else + *conf = alt2; + } + } + } else { + /* Straight fit */ + memset(conf, 0, sizeof(*conf)); + conf->div = parent_rate / rate; + } + + return conf->freq; +} + +static int s5_pll_enable(struct clk_hw *hw) +{ + struct s5_hw_clk *pll = to_s5_pll(hw); + u32 val = readl(pll->reg); + + val |= PLL_CLK_ENA; + writel(val, pll->reg); + + return 0; +} + +static void s5_pll_disable(struct clk_hw *hw) +{ + struct s5_hw_clk *pll = to_s5_pll(hw); + u32 val = readl(pll->reg); + + val &= ~PLL_CLK_ENA; + writel(val, pll->reg); +} + +static int s5_pll_set_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long parent_rate) +{ + struct s5_hw_clk *pll = to_s5_pll(hw); + struct s5_pll_conf conf; + unsigned long eff_rate; + u32 val; + + eff_rate = s5_calc_params(rate, parent_rate, &conf); + if (eff_rate != rate) + return -EOPNOTSUPP; + + val = readl(pll->reg) & PLL_CLK_ENA; + val |= FIELD_PREP(PLL_DIV, conf.div); + if (conf.rot_ena) { + val |= PLL_ROT_ENA; + val |= FIELD_PREP(PLL_ROT_SEL, conf.rot_sel); + val |= FIELD_PREP(PLL_PRE_DIV, conf.pre_div); + if (conf.rot_dir) + val |= PLL_ROT_DIR; + } + writel(val, pll->reg); + + return 0; +} + +static unsigned long s5_pll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct s5_hw_clk *pll = to_s5_pll(hw); + struct s5_pll_conf conf; + u32 val; + + val = readl(pll->reg); + + if (val & PLL_CLK_ENA) { + conf.div = FIELD_GET(PLL_DIV, val); + conf.pre_div = FIELD_GET(PLL_PRE_DIV, val); + conf.rot_ena = FIELD_GET(PLL_ROT_ENA, val); + conf.rot_dir = FIELD_GET(PLL_ROT_DIR, val); + conf.rot_sel = FIELD_GET(PLL_ROT_SEL, val); + + conf.freq = s5_calc_freq(parent_rate, &conf); + } else { + conf.freq = 0; + } + + return conf.freq; +} + +static long s5_pll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct s5_pll_conf conf; + + return s5_calc_params(rate, *parent_rate, &conf); +} + +static const struct clk_ops s5_pll_ops = { + .enable = s5_pll_enable, + .disable = s5_pll_disable, + .set_rate = s5_pll_set_rate, + .round_rate = s5_pll_round_rate, + .recalc_rate = s5_pll_recalc_rate, +}; + +static struct clk_hw *s5_clk_hw_get(struct of_phandle_args *clkspec, void *data) +{ + struct s5_clk_data *s5_clk = data; + unsigned int idx = clkspec->args[0]; + + if (idx >= N_CLOCKS) { + pr_err("%s: invalid index %u\n", __func__, idx); + return ERR_PTR(-EINVAL); + } + + return &s5_clk->s5_hw[idx].hw; +} + +static int s5_clk_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + int i, ret; + struct s5_clk_data *s5_clk; + struct clk_parent_data pdata = { .index = 0 }; + struct clk_init_data init = { + .ops = &s5_pll_ops, + .num_parents = 1, + .parent_data = &pdata, + }; + + s5_clk = devm_kzalloc(dev, sizeof(*s5_clk), GFP_KERNEL); + if (!s5_clk) + return -ENOMEM; + + s5_clk->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(s5_clk->base)) + return PTR_ERR(s5_clk->base); + + for (i = 0; i < N_CLOCKS; i++) { + struct s5_hw_clk *s5_hw = &s5_clk->s5_hw[i]; + + init.name = clk_names[i]; + s5_hw->reg = s5_clk->base + (i * 4); + s5_hw->hw.init = &init; + ret = devm_clk_hw_register(dev, &s5_hw->hw); + if (ret) { + dev_err(dev, "failed to register %s clock\n", + init.name); + return ret; + } + } + + return devm_of_clk_add_hw_provider(dev, s5_clk_hw_get, s5_clk); +} + +static const struct of_device_id s5_clk_dt_ids[] = { + { .compatible = "microchip,sparx5-dpll", }, + { } +}; +MODULE_DEVICE_TABLE(of, s5_clk_dt_ids); + +static struct platform_driver s5_clk_driver = { + .probe = s5_clk_probe, + .driver = { + .name = "sparx5-clk", + .of_match_table = s5_clk_dt_ids, + }, +}; +builtin_platform_driver(s5_clk_driver); |