diff options
Diffstat (limited to 'drivers/clk/clk-stm32f4.c')
| -rw-r--r-- | drivers/clk/clk-stm32f4.c | 155 |
1 files changed, 149 insertions, 6 deletions
diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c index 07c13ebe327d..f476883bc93b 100644 --- a/drivers/clk/clk-stm32f4.c +++ b/drivers/clk/clk-stm32f4.c @@ -5,6 +5,7 @@ * Inspired by clk-asm9260.c . */ +#include <linux/bitfield.h> #include <linux/clk-provider.h> #include <linux/err.h> #include <linux/io.h> @@ -34,11 +35,20 @@ #define STM32F4_RCC_APB2ENR 0x44 #define STM32F4_RCC_BDCR 0x70 #define STM32F4_RCC_CSR 0x74 +#define STM32F4_RCC_SSCGR 0x80 #define STM32F4_RCC_PLLI2SCFGR 0x84 #define STM32F4_RCC_PLLSAICFGR 0x88 #define STM32F4_RCC_DCKCFGR 0x8c #define STM32F7_RCC_DCKCFGR2 0x90 +#define STM32F4_RCC_PLLCFGR_N_MASK GENMASK(14, 6) + +#define STM32F4_RCC_SSCGR_SSCGEN BIT(31) +#define STM32F4_RCC_SSCGR_SPREADSEL BIT(30) +#define STM32F4_RCC_SSCGR_RESERVED_MASK GENMASK(29, 28) +#define STM32F4_RCC_SSCGR_INCSTEP_MASK GENMASK(27, 13) +#define STM32F4_RCC_SSCGR_MODPER_MASK GENMASK(12, 0) + #define NONE -1 #define NO_IDX NONE #define NO_MUX NONE @@ -364,6 +374,16 @@ static const struct stm32f4_gate_data stm32f769_gates[] __initconst = { { STM32F4_RCC_APB2ENR, 30, "mdio", "apb2_div" }, }; +enum stm32f4_pll_ssc_mod_type { + STM32F4_PLL_SSC_CENTER_SPREAD, + STM32F4_PLL_SSC_DOWN_SPREAD, +}; + +static const char * const stm32f4_ssc_mod_methods[] __initconst = { + [STM32F4_PLL_SSC_DOWN_SPREAD] = "down-spread", + [STM32F4_PLL_SSC_CENTER_SPREAD] = "center-spread", +}; + /* * This bitmask tells us which bit offsets (0..192) on STM32F4[23]xxx * have gate bits associated with them. Its combined hweight is 71. @@ -509,6 +529,12 @@ static const struct clk_div_table pll_divr_table[] = { { 2, 2 }, { 3, 3 }, { 4, 4 }, { 5, 5 }, { 6, 6 }, { 7, 7 }, { 0 } }; +struct stm32f4_pll_ssc { + unsigned int mod_freq; + unsigned int mod_depth; + enum stm32f4_pll_ssc_mod_type mod_type; +}; + struct stm32f4_pll { spinlock_t *lock; struct clk_gate gate; @@ -516,6 +542,8 @@ struct stm32f4_pll { u8 bit_rdy_idx; u8 status; u8 n_start; + bool ssc_enable; + struct stm32f4_pll_ssc ssc_conf; }; #define to_stm32f4_pll(_gate) container_of(_gate, struct stm32f4_pll, gate) @@ -538,6 +566,7 @@ struct stm32f4_vco_data { u8 offset; u8 bit_idx; u8 bit_rdy_idx; + bool sscg; }; static const struct stm32f4_vco_data vco_data[] = { @@ -632,9 +661,11 @@ static unsigned long stm32f4_pll_recalc(struct clk_hw *hw, { struct clk_gate *gate = to_clk_gate(hw); struct stm32f4_pll *pll = to_stm32f4_pll(gate); + unsigned long val; unsigned long n; - n = (readl(base + pll->offset) >> 6) & 0x1ff; + val = readl(base + pll->offset); + n = FIELD_GET(STM32F4_RCC_PLLCFGR_N_MASK, val); return parent_rate * n; } @@ -656,6 +687,32 @@ static long stm32f4_pll_round_rate(struct clk_hw *hw, unsigned long rate, return *prate * n; } +static void stm32f4_pll_set_ssc(struct clk_hw *hw, unsigned long parent_rate, + unsigned int ndiv) +{ + struct clk_gate *gate = to_clk_gate(hw); + struct stm32f4_pll *pll = to_stm32f4_pll(gate); + struct stm32f4_pll_ssc *ssc = &pll->ssc_conf; + u32 modeper, incstep; + u32 sscgr; + + sscgr = readl(base + STM32F4_RCC_SSCGR); + /* reserved field must be kept at reset value */ + sscgr &= STM32F4_RCC_SSCGR_RESERVED_MASK; + + modeper = DIV_ROUND_CLOSEST(parent_rate, 4 * ssc->mod_freq); + incstep = DIV_ROUND_CLOSEST(((1 << 15) - 1) * ssc->mod_depth * ndiv, + 5 * 10000 * modeper); + sscgr |= STM32F4_RCC_SSCGR_SSCGEN | + FIELD_PREP(STM32F4_RCC_SSCGR_INCSTEP_MASK, incstep) | + FIELD_PREP(STM32F4_RCC_SSCGR_MODPER_MASK, modeper); + + if (ssc->mod_type) + sscgr |= STM32F4_RCC_SSCGR_SPREADSEL; + + writel(sscgr, base + STM32F4_RCC_SSCGR); +} + static int stm32f4_pll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { @@ -673,9 +730,13 @@ static int stm32f4_pll_set_rate(struct clk_hw *hw, unsigned long rate, n = rate / parent_rate; - val = readl(base + pll->offset) & ~(0x1ff << 6); + val = readl(base + pll->offset) & ~STM32F4_RCC_PLLCFGR_N_MASK; + val |= FIELD_PREP(STM32F4_RCC_PLLCFGR_N_MASK, n); + + writel(val, base + pll->offset); - writel(val | ((n & 0x1ff) << 6), base + pll->offset); + if (pll->ssc_enable) + stm32f4_pll_set_ssc(hw, parent_rate, n); if (pll_state) stm32f4_pll_enable(hw); @@ -782,6 +843,84 @@ static struct clk_hw *clk_register_pll_div(const char *name, return hw; } +static int __init stm32f4_pll_init_ssc(struct clk_hw *hw, + const struct stm32f4_pll_ssc *conf) +{ + struct clk_gate *gate = to_clk_gate(hw); + struct stm32f4_pll *pll = to_stm32f4_pll(gate); + struct clk_hw *parent; + unsigned long parent_rate; + int pll_state; + unsigned long n, val; + + parent = clk_hw_get_parent(hw); + if (!parent) { + pr_err("%s: failed to get clock parent\n", __func__); + return -ENODEV; + } + + parent_rate = clk_hw_get_rate(parent); + + pll->ssc_enable = true; + memcpy(&pll->ssc_conf, conf, sizeof(pll->ssc_conf)); + + pll_state = stm32f4_pll_is_enabled(hw); + + if (pll_state) + stm32f4_pll_disable(hw); + + val = readl(base + pll->offset); + n = FIELD_GET(STM32F4_RCC_PLLCFGR_N_MASK, val); + + pr_debug("%s: pll: %s, parent: %s, parent-rate: %lu, n: %lu\n", + __func__, clk_hw_get_name(hw), clk_hw_get_name(parent), + parent_rate, n); + + stm32f4_pll_set_ssc(hw, parent_rate, n); + + if (pll_state) + stm32f4_pll_enable(hw); + + return 0; +} + +static int __init stm32f4_pll_ssc_parse_dt(struct device_node *np, + struct stm32f4_pll_ssc *conf) +{ + int ret; + const char *s; + + if (!conf) + return -EINVAL; + + ret = of_property_read_u32(np, "st,ssc-modfreq-hz", &conf->mod_freq); + if (ret) + return ret; + + ret = of_property_read_u32(np, "st,ssc-moddepth-permyriad", + &conf->mod_depth); + if (ret) { + pr_err("%pOF: missing st,ssc-moddepth-permyriad\n", np); + return ret; + } + + ret = fwnode_property_match_property_string(of_fwnode_handle(np), + "st,ssc-modmethod", + stm32f4_ssc_mod_methods, + ARRAY_SIZE(stm32f4_ssc_mod_methods)); + if (ret < 0) { + pr_err("%pOF: failed to get st,ssc-modmethod\n", np); + return ret; + } + + conf->mod_type = ret; + + pr_debug("%pOF: SSCG settings: mod_freq: %d, mod_depth: %d mod_method: %s [%d]\n", + np, conf->mod_freq, conf->mod_depth, s, conf->mod_type); + + return 0; +} + static struct clk_hw *stm32f4_rcc_register_pll(const char *pllsrc, const struct stm32f4_pll_data *data, spinlock_t *lock) { @@ -1689,7 +1828,8 @@ static void __init stm32f4_rcc_init(struct device_node *np) const struct of_device_id *match; const struct stm32f4_clk_data *data; unsigned long pllm; - struct clk_hw *pll_src_hw; + struct clk_hw *pll_src_hw, *pll_vco_hw; + struct stm32f4_pll_ssc ssc_conf; base = of_iomap(np, 0); if (!base) { @@ -1748,8 +1888,8 @@ static void __init stm32f4_rcc_init(struct device_node *np) clk_hw_register_fixed_factor(NULL, "vco_in", pll_src, 0, 1, pllm); - stm32f4_rcc_register_pll("vco_in", &data->pll_data[0], - &stm32f4_clk_lock); + pll_vco_hw = stm32f4_rcc_register_pll("vco_in", &data->pll_data[0], + &stm32f4_clk_lock); clks[PLL_VCO_I2S] = stm32f4_rcc_register_pll("vco_in", &data->pll_data[1], &stm32f4_clk_lock); @@ -1894,6 +2034,9 @@ static void __init stm32f4_rcc_init(struct device_node *np) of_clk_add_hw_provider(np, stm32f4_rcc_lookup_clk, NULL); + if (!stm32f4_pll_ssc_parse_dt(np, &ssc_conf)) + stm32f4_pll_init_ssc(pll_vco_hw, &ssc_conf); + return; fail: kfree(clks); |