1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright 2019 NXP 4 * 5 * Clock driver for LS1028A Display output interfaces(LCD, DPHY). 6 */ 7 8 #include <linux/clk-provider.h> 9 #include <linux/device.h> 10 #include <linux/module.h> 11 #include <linux/err.h> 12 #include <linux/io.h> 13 #include <linux/iopoll.h> 14 #include <linux/of.h> 15 #include <linux/platform_device.h> 16 #include <linux/slab.h> 17 #include <linux/bitfield.h> 18 19 /* PLLDIG register offsets and bit masks */ 20 #define PLLDIG_REG_PLLSR 0x24 21 #define PLLDIG_LOCK_MASK BIT(2) 22 #define PLLDIG_REG_PLLDV 0x28 23 #define PLLDIG_MFD_MASK GENMASK(7, 0) 24 #define PLLDIG_RFDPHI1_MASK GENMASK(30, 25) 25 #define PLLDIG_REG_PLLFM 0x2c 26 #define PLLDIG_SSCGBYP_ENABLE BIT(30) 27 #define PLLDIG_REG_PLLFD 0x30 28 #define PLLDIG_FDEN BIT(30) 29 #define PLLDIG_FRAC_MASK GENMASK(15, 0) 30 #define PLLDIG_REG_PLLCAL1 0x38 31 #define PLLDIG_REG_PLLCAL2 0x3c 32 33 /* Range of the VCO frequencies, in Hz */ 34 #define PLLDIG_MIN_VCO_FREQ 650000000 35 #define PLLDIG_MAX_VCO_FREQ 1300000000 36 37 /* Range of the output frequencies, in Hz */ 38 #define PHI1_MIN_FREQ 27000000UL 39 #define PHI1_MAX_FREQ 600000000UL 40 41 /* Maximum value of the reduced frequency divider */ 42 #define MAX_RFDPHI1 63UL 43 44 /* Best value of multiplication factor divider */ 45 #define PLLDIG_DEFAULT_MFD 44 46 47 /* 48 * Denominator part of the fractional part of the 49 * loop multiplication factor. 50 */ 51 #define MFDEN 20480 52 53 static const struct clk_parent_data parent_data[] = { 54 { .index = 0 }, 55 }; 56 57 struct clk_plldig { 58 struct clk_hw hw; 59 void __iomem *regs; 60 unsigned int vco_freq; 61 }; 62 63 #define to_clk_plldig(_hw) container_of(_hw, struct clk_plldig, hw) 64 65 static int plldig_enable(struct clk_hw *hw) 66 { 67 struct clk_plldig *data = to_clk_plldig(hw); 68 u32 val; 69 70 val = readl(data->regs + PLLDIG_REG_PLLFM); 71 /* 72 * Use Bypass mode with PLL off by default, the frequency overshoot 73 * detector output was disable. SSCG Bypass mode should be enable. 74 */ 75 val |= PLLDIG_SSCGBYP_ENABLE; 76 writel(val, data->regs + PLLDIG_REG_PLLFM); 77 78 return 0; 79 } 80 81 static void plldig_disable(struct clk_hw *hw) 82 { 83 struct clk_plldig *data = to_clk_plldig(hw); 84 u32 val; 85 86 val = readl(data->regs + PLLDIG_REG_PLLFM); 87 88 val &= ~PLLDIG_SSCGBYP_ENABLE; 89 val |= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0); 90 91 writel(val, data->regs + PLLDIG_REG_PLLFM); 92 } 93 94 static int plldig_is_enabled(struct clk_hw *hw) 95 { 96 struct clk_plldig *data = to_clk_plldig(hw); 97 98 return readl(data->regs + PLLDIG_REG_PLLFM) & 99 PLLDIG_SSCGBYP_ENABLE; 100 } 101 102 static unsigned long plldig_recalc_rate(struct clk_hw *hw, 103 unsigned long parent_rate) 104 { 105 struct clk_plldig *data = to_clk_plldig(hw); 106 u32 val, rfdphi1; 107 108 val = readl(data->regs + PLLDIG_REG_PLLDV); 109 110 /* Check if PLL is bypassed */ 111 if (val & PLLDIG_SSCGBYP_ENABLE) 112 return parent_rate; 113 114 rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val); 115 116 /* 117 * If RFDPHI1 has a value of 1 the VCO frequency is also divided by 118 * one. 119 */ 120 if (!rfdphi1) 121 rfdphi1 = 1; 122 123 return DIV_ROUND_UP(data->vco_freq, rfdphi1); 124 } 125 126 static unsigned long plldig_calc_target_div(unsigned long vco_freq, 127 unsigned long target_rate) 128 { 129 unsigned long div; 130 131 div = DIV_ROUND_CLOSEST(vco_freq, target_rate); 132 div = clamp(div, 1UL, MAX_RFDPHI1); 133 134 return div; 135 } 136 137 static int plldig_determine_rate(struct clk_hw *hw, 138 struct clk_rate_request *req) 139 { 140 struct clk_plldig *data = to_clk_plldig(hw); 141 unsigned int div; 142 143 req->rate = clamp(req->rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ); 144 div = plldig_calc_target_div(data->vco_freq, req->rate); 145 req->rate = DIV_ROUND_UP(data->vco_freq, div); 146 147 return 0; 148 } 149 150 static int plldig_set_rate(struct clk_hw *hw, unsigned long rate, 151 unsigned long parent_rate) 152 { 153 struct clk_plldig *data = to_clk_plldig(hw); 154 unsigned int val, cond; 155 unsigned int rfdphi1; 156 157 rate = clamp(rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ); 158 rfdphi1 = plldig_calc_target_div(data->vco_freq, rate); 159 160 /* update the divider value */ 161 val = readl(data->regs + PLLDIG_REG_PLLDV); 162 val &= ~PLLDIG_RFDPHI1_MASK; 163 val |= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1); 164 writel(val, data->regs + PLLDIG_REG_PLLDV); 165 166 /* waiting for old lock state to clear */ 167 udelay(200); 168 169 /* Wait until PLL is locked or timeout */ 170 return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond, 171 cond & PLLDIG_LOCK_MASK, 0, 172 USEC_PER_MSEC); 173 } 174 175 static const struct clk_ops plldig_clk_ops = { 176 .enable = plldig_enable, 177 .disable = plldig_disable, 178 .is_enabled = plldig_is_enabled, 179 .recalc_rate = plldig_recalc_rate, 180 .determine_rate = plldig_determine_rate, 181 .set_rate = plldig_set_rate, 182 }; 183 184 static int plldig_init(struct clk_hw *hw) 185 { 186 struct clk_plldig *data = to_clk_plldig(hw); 187 struct clk_hw *parent = clk_hw_get_parent(hw); 188 unsigned long parent_rate; 189 unsigned long val; 190 unsigned long long lltmp; 191 unsigned int mfd, fracdiv = 0; 192 193 if (!parent) 194 return -EINVAL; 195 196 parent_rate = clk_hw_get_rate(parent); 197 198 if (data->vco_freq) { 199 mfd = data->vco_freq / parent_rate; 200 lltmp = data->vco_freq % parent_rate; 201 lltmp *= MFDEN; 202 do_div(lltmp, parent_rate); 203 fracdiv = lltmp; 204 } else { 205 mfd = PLLDIG_DEFAULT_MFD; 206 data->vco_freq = parent_rate * mfd; 207 } 208 209 val = FIELD_PREP(PLLDIG_MFD_MASK, mfd); 210 writel(val, data->regs + PLLDIG_REG_PLLDV); 211 212 /* Enable fractional divider */ 213 if (fracdiv) { 214 val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv); 215 val |= PLLDIG_FDEN; 216 writel(val, data->regs + PLLDIG_REG_PLLFD); 217 } 218 219 return 0; 220 } 221 222 static int plldig_clk_probe(struct platform_device *pdev) 223 { 224 struct clk_plldig *data; 225 struct device *dev = &pdev->dev; 226 int ret; 227 228 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 229 if (!data) 230 return -ENOMEM; 231 232 data->regs = devm_platform_ioremap_resource(pdev, 0); 233 if (IS_ERR(data->regs)) 234 return PTR_ERR(data->regs); 235 236 data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk", 237 parent_data, 238 &plldig_clk_ops, 239 0); 240 241 ret = devm_clk_hw_register(dev, &data->hw); 242 if (ret) { 243 dev_err(dev, "failed to register %s clock\n", 244 dev->of_node->name); 245 return ret; 246 } 247 248 ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, 249 &data->hw); 250 if (ret) { 251 dev_err(dev, "unable to add clk provider\n"); 252 return ret; 253 } 254 255 /* 256 * The frequency of the VCO cannot be changed during runtime. 257 * Therefore, let the user specify a desired frequency. 258 */ 259 if (!of_property_read_u32(dev->of_node, "fsl,vco-hz", 260 &data->vco_freq)) { 261 if (data->vco_freq < PLLDIG_MIN_VCO_FREQ || 262 data->vco_freq > PLLDIG_MAX_VCO_FREQ) 263 return -EINVAL; 264 } 265 266 return plldig_init(&data->hw); 267 } 268 269 static const struct of_device_id plldig_clk_id[] = { 270 { .compatible = "fsl,ls1028a-plldig" }, 271 { } 272 }; 273 MODULE_DEVICE_TABLE(of, plldig_clk_id); 274 275 static struct platform_driver plldig_clk_driver = { 276 .driver = { 277 .name = "plldig-clock", 278 .of_match_table = plldig_clk_id, 279 }, 280 .probe = plldig_clk_probe, 281 }; 282 module_platform_driver(plldig_clk_driver); 283 284 MODULE_LICENSE("GPL v2"); 285 MODULE_AUTHOR("Wen He <wen.he_1@nxp.com>"); 286 MODULE_DESCRIPTION("LS1028A Display output interface pixel clock driver"); 287