1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2018 NXP. 4 * 5 * This driver supports the fractional plls found in the imx8m SOCs 6 * 7 * Documentation for this fractional pll can be found at: 8 * https://www.nxp.com/docs/en/reference-manual/IMX8MDQLQRM.pdf#page=834 9 */ 10 11 #include <linux/clk-provider.h> 12 #include <linux/err.h> 13 #include <linux/export.h> 14 #include <linux/io.h> 15 #include <linux/iopoll.h> 16 #include <linux/slab.h> 17 #include <linux/bitfield.h> 18 19 #include "clk.h" 20 21 #define PLL_CFG0 0x0 22 #define PLL_CFG1 0x4 23 24 #define PLL_LOCK_STATUS BIT(31) 25 #define PLL_PD_MASK BIT(19) 26 #define PLL_BYPASS_MASK BIT(14) 27 #define PLL_NEWDIV_VAL BIT(12) 28 #define PLL_NEWDIV_ACK BIT(11) 29 #define PLL_FRAC_DIV_MASK GENMASK(30, 7) 30 #define PLL_INT_DIV_MASK GENMASK(6, 0) 31 #define PLL_OUTPUT_DIV_MASK GENMASK(4, 0) 32 #define PLL_FRAC_DENOM 0x1000000 33 34 #define PLL_FRAC_LOCK_TIMEOUT 10000 35 #define PLL_FRAC_ACK_TIMEOUT 500000 36 37 struct clk_frac_pll { 38 struct clk_hw hw; 39 void __iomem *base; 40 }; 41 42 #define to_clk_frac_pll(_hw) container_of(_hw, struct clk_frac_pll, hw) 43 44 static int clk_wait_lock(struct clk_frac_pll *pll) 45 { 46 u32 val; 47 48 return readl_poll_timeout(pll->base, val, val & PLL_LOCK_STATUS, 0, 49 PLL_FRAC_LOCK_TIMEOUT); 50 } 51 52 static int clk_wait_ack(struct clk_frac_pll *pll) 53 { 54 u32 val; 55 56 /* return directly if the pll is in powerdown or in bypass */ 57 if (readl_relaxed(pll->base) & (PLL_PD_MASK | PLL_BYPASS_MASK)) 58 return 0; 59 60 /* Wait for the pll's divfi and divff to be reloaded */ 61 return readl_poll_timeout(pll->base, val, val & PLL_NEWDIV_ACK, 0, 62 PLL_FRAC_ACK_TIMEOUT); 63 } 64 65 static int clk_pll_prepare(struct clk_hw *hw) 66 { 67 struct clk_frac_pll *pll = to_clk_frac_pll(hw); 68 u32 val; 69 70 val = readl_relaxed(pll->base + PLL_CFG0); 71 val &= ~PLL_PD_MASK; 72 writel_relaxed(val, pll->base + PLL_CFG0); 73 74 return clk_wait_lock(pll); 75 } 76 77 static void clk_pll_unprepare(struct clk_hw *hw) 78 { 79 struct clk_frac_pll *pll = to_clk_frac_pll(hw); 80 u32 val; 81 82 val = readl_relaxed(pll->base + PLL_CFG0); 83 val |= PLL_PD_MASK; 84 writel_relaxed(val, pll->base + PLL_CFG0); 85 } 86 87 static int clk_pll_is_prepared(struct clk_hw *hw) 88 { 89 struct clk_frac_pll *pll = to_clk_frac_pll(hw); 90 u32 val; 91 92 val = readl_relaxed(pll->base + PLL_CFG0); 93 return (val & PLL_PD_MASK) ? 0 : 1; 94 } 95 96 static unsigned long clk_pll_recalc_rate(struct clk_hw *hw, 97 unsigned long parent_rate) 98 { 99 struct clk_frac_pll *pll = to_clk_frac_pll(hw); 100 u32 val, divff, divfi, divq; 101 u64 temp64 = parent_rate; 102 u64 rate; 103 104 val = readl_relaxed(pll->base + PLL_CFG0); 105 divq = (FIELD_GET(PLL_OUTPUT_DIV_MASK, val) + 1) * 2; 106 val = readl_relaxed(pll->base + PLL_CFG1); 107 divff = FIELD_GET(PLL_FRAC_DIV_MASK, val); 108 divfi = FIELD_GET(PLL_INT_DIV_MASK, val); 109 110 temp64 *= 8; 111 temp64 *= divff; 112 do_div(temp64, PLL_FRAC_DENOM); 113 do_div(temp64, divq); 114 115 rate = parent_rate * 8 * (divfi + 1); 116 do_div(rate, divq); 117 rate += temp64; 118 119 return rate; 120 } 121 122 static int clk_pll_determine_rate(struct clk_hw *hw, 123 struct clk_rate_request *req) 124 { 125 u64 parent_rate = req->best_parent_rate; 126 u32 divff, divfi; 127 u64 temp64; 128 129 parent_rate *= 8; 130 req->rate *= 2; 131 temp64 = req->rate; 132 do_div(temp64, parent_rate); 133 divfi = temp64; 134 temp64 = req->rate - divfi * parent_rate; 135 temp64 *= PLL_FRAC_DENOM; 136 do_div(temp64, parent_rate); 137 divff = temp64; 138 139 temp64 = parent_rate; 140 temp64 *= divff; 141 do_div(temp64, PLL_FRAC_DENOM); 142 143 req->rate = parent_rate * divfi + temp64; 144 145 req->rate = req->rate / 2; 146 147 return 0; 148 } 149 150 /* 151 * To simplify the clock calculation, we can keep the 'PLL_OUTPUT_VAL' at zero 152 * (means the PLL output will be divided by 2). So the PLL output can use 153 * the below formula: 154 * pllout = parent_rate * 8 / 2 * DIVF_VAL; 155 * where DIVF_VAL = 1 + DIVFI + DIVFF / 2^24. 156 */ 157 static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, 158 unsigned long parent_rate) 159 { 160 struct clk_frac_pll *pll = to_clk_frac_pll(hw); 161 u32 val, divfi, divff; 162 u64 temp64; 163 int ret; 164 165 parent_rate *= 8; 166 rate *= 2; 167 divfi = rate / parent_rate; 168 temp64 = parent_rate * divfi; 169 temp64 = rate - temp64; 170 temp64 *= PLL_FRAC_DENOM; 171 do_div(temp64, parent_rate); 172 divff = temp64; 173 174 val = readl_relaxed(pll->base + PLL_CFG1); 175 val &= ~(PLL_FRAC_DIV_MASK | PLL_INT_DIV_MASK); 176 val |= (divff << 7) | (divfi - 1); 177 writel_relaxed(val, pll->base + PLL_CFG1); 178 179 val = readl_relaxed(pll->base + PLL_CFG0); 180 val &= ~0x1f; 181 writel_relaxed(val, pll->base + PLL_CFG0); 182 183 /* Set the NEV_DIV_VAL to reload the DIVFI and DIVFF */ 184 val = readl_relaxed(pll->base + PLL_CFG0); 185 val |= PLL_NEWDIV_VAL; 186 writel_relaxed(val, pll->base + PLL_CFG0); 187 188 ret = clk_wait_ack(pll); 189 190 /* clear the NEV_DIV_VAL */ 191 val = readl_relaxed(pll->base + PLL_CFG0); 192 val &= ~PLL_NEWDIV_VAL; 193 writel_relaxed(val, pll->base + PLL_CFG0); 194 195 return ret; 196 } 197 198 static const struct clk_ops clk_frac_pll_ops = { 199 .prepare = clk_pll_prepare, 200 .unprepare = clk_pll_unprepare, 201 .is_prepared = clk_pll_is_prepared, 202 .recalc_rate = clk_pll_recalc_rate, 203 .determine_rate = clk_pll_determine_rate, 204 .set_rate = clk_pll_set_rate, 205 }; 206 207 struct clk_hw *imx_clk_hw_frac_pll(const char *name, 208 const char *parent_name, 209 void __iomem *base) 210 { 211 struct clk_init_data init; 212 struct clk_frac_pll *pll; 213 struct clk_hw *hw; 214 int ret; 215 216 pll = kzalloc(sizeof(*pll), GFP_KERNEL); 217 if (!pll) 218 return ERR_PTR(-ENOMEM); 219 220 init.name = name; 221 init.ops = &clk_frac_pll_ops; 222 init.flags = 0; 223 init.parent_names = &parent_name; 224 init.num_parents = 1; 225 226 pll->base = base; 227 pll->hw.init = &init; 228 229 hw = &pll->hw; 230 231 ret = clk_hw_register(NULL, hw); 232 if (ret) { 233 kfree(pll); 234 return ERR_PTR(ret); 235 } 236 237 return hw; 238 } 239 EXPORT_SYMBOL_GPL(imx_clk_hw_frac_pll); 240