1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2014 Free Electrons 4 * Copyright (C) 2014 Atmel 5 * 6 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com> 7 */ 8 9 #include <linux/clk.h> 10 #include <linux/delay.h> 11 #include <linux/mfd/atmel-hlcdc.h> 12 #include <linux/module.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/pwm.h> 16 #include <linux/regmap.h> 17 18 #define ATMEL_HLCDC_PWMCVAL_MASK GENMASK(15, 8) 19 #define ATMEL_HLCDC_PWMCVAL(x) (((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK) 20 #define ATMEL_HLCDC_PWMPOL BIT(4) 21 #define ATMEL_HLCDC_PWMPS_MASK GENMASK(2, 0) 22 #define ATMEL_HLCDC_PWMPS_MAX 0x6 23 #define ATMEL_HLCDC_PWMPS(x) ((x) & ATMEL_HLCDC_PWMPS_MASK) 24 25 struct atmel_hlcdc_pwm_errata { 26 bool slow_clk_erratum; 27 bool div1_clk_erratum; 28 }; 29 30 struct atmel_hlcdc_pwm { 31 struct atmel_hlcdc *hlcdc; 32 struct clk *cur_clk; 33 const struct atmel_hlcdc_pwm_errata *errata; 34 }; 35 36 static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip) 37 { 38 return pwmchip_get_drvdata(chip); 39 } 40 41 static int atmel_hlcdc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 42 const struct pwm_state *state) 43 { 44 struct atmel_hlcdc_pwm *atmel = to_atmel_hlcdc_pwm(chip); 45 struct atmel_hlcdc *hlcdc = atmel->hlcdc; 46 unsigned int status; 47 int ret; 48 49 if (state->enabled) { 50 struct clk *new_clk = hlcdc->slow_clk; 51 u64 pwmcval = state->duty_cycle * 256; 52 unsigned long clk_freq; 53 u64 clk_period_ns; 54 u32 pwmcfg; 55 int pres; 56 57 if (!atmel->errata || !atmel->errata->slow_clk_erratum) { 58 clk_freq = clk_get_rate(new_clk); 59 if (!clk_freq) 60 return -EINVAL; 61 62 clk_period_ns = (u64)NSEC_PER_SEC * 256; 63 do_div(clk_period_ns, clk_freq); 64 } 65 66 /* Errata: cannot use slow clk on some IP revisions */ 67 if ((atmel->errata && atmel->errata->slow_clk_erratum) || 68 clk_period_ns > state->period) { 69 new_clk = hlcdc->sys_clk; 70 clk_freq = clk_get_rate(new_clk); 71 if (!clk_freq) 72 return -EINVAL; 73 74 clk_period_ns = (u64)NSEC_PER_SEC * 256; 75 do_div(clk_period_ns, clk_freq); 76 } 77 78 for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) { 79 /* Errata: cannot divide by 1 on some IP revisions */ 80 if (!pres && atmel->errata && 81 atmel->errata->div1_clk_erratum) 82 continue; 83 84 if ((clk_period_ns << pres) >= state->period) 85 break; 86 } 87 88 if (pres > ATMEL_HLCDC_PWMPS_MAX) 89 return -EINVAL; 90 91 pwmcfg = ATMEL_HLCDC_PWMPS(pres); 92 93 if (new_clk != atmel->cur_clk) { 94 u32 gencfg = 0; 95 int ret; 96 97 ret = clk_prepare_enable(new_clk); 98 if (ret) 99 return ret; 100 101 clk_disable_unprepare(atmel->cur_clk); 102 atmel->cur_clk = new_clk; 103 104 if (new_clk == hlcdc->sys_clk) 105 gencfg = ATMEL_HLCDC_CLKPWMSEL; 106 107 ret = regmap_update_bits(hlcdc->regmap, 108 ATMEL_HLCDC_CFG(0), 109 ATMEL_HLCDC_CLKPWMSEL, 110 gencfg); 111 if (ret) 112 return ret; 113 } 114 115 do_div(pwmcval, state->period); 116 117 /* 118 * The PWM duty cycle is configurable from 0/256 to 255/256 of 119 * the period cycle. Hence we can't set a duty cycle occupying 120 * the whole period cycle if we're asked to. 121 * Set it to 255 if pwmcval is greater than 256. 122 */ 123 if (pwmcval > 255) 124 pwmcval = 255; 125 126 pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval); 127 128 if (state->polarity == PWM_POLARITY_NORMAL) 129 pwmcfg |= ATMEL_HLCDC_PWMPOL; 130 131 ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6), 132 ATMEL_HLCDC_PWMCVAL_MASK | 133 ATMEL_HLCDC_PWMPS_MASK | 134 ATMEL_HLCDC_PWMPOL, 135 pwmcfg); 136 if (ret) 137 return ret; 138 139 ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, 140 ATMEL_HLCDC_PWM); 141 if (ret) 142 return ret; 143 144 ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR, 145 status, 146 status & ATMEL_HLCDC_PWM, 147 10, 0); 148 if (ret) 149 return ret; 150 } else { 151 ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, 152 ATMEL_HLCDC_PWM); 153 if (ret) 154 return ret; 155 156 ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR, 157 status, 158 !(status & ATMEL_HLCDC_PWM), 159 10, 0); 160 if (ret) 161 return ret; 162 163 clk_disable_unprepare(atmel->cur_clk); 164 atmel->cur_clk = NULL; 165 } 166 167 return 0; 168 } 169 170 static const struct pwm_ops atmel_hlcdc_pwm_ops = { 171 .apply = atmel_hlcdc_pwm_apply, 172 }; 173 174 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = { 175 .slow_clk_erratum = true, 176 }; 177 178 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = { 179 .div1_clk_erratum = true, 180 }; 181 182 static int atmel_hlcdc_pwm_suspend(struct device *dev) 183 { 184 struct pwm_chip *chip = dev_get_drvdata(dev); 185 struct atmel_hlcdc_pwm *atmel = to_atmel_hlcdc_pwm(chip); 186 struct pwm_device *pwm = &chip->pwms[0]; 187 188 /* Keep the periph clock enabled if the PWM is still running. */ 189 if (!pwm->state.enabled) 190 clk_disable_unprepare(atmel->hlcdc->periph_clk); 191 192 return 0; 193 } 194 195 static int atmel_hlcdc_pwm_resume(struct device *dev) 196 { 197 struct pwm_chip *chip = dev_get_drvdata(dev); 198 struct atmel_hlcdc_pwm *atmel = to_atmel_hlcdc_pwm(chip); 199 struct pwm_device *pwm = &chip->pwms[0]; 200 int ret; 201 202 /* Re-enable the periph clock it was stopped during suspend. */ 203 if (!pwm->state.enabled) { 204 ret = clk_prepare_enable(atmel->hlcdc->periph_clk); 205 if (ret) 206 return ret; 207 } 208 209 return atmel_hlcdc_pwm_apply(chip, pwm, &pwm->state); 210 } 211 212 static DEFINE_SIMPLE_DEV_PM_OPS(atmel_hlcdc_pwm_pm_ops, 213 atmel_hlcdc_pwm_suspend, atmel_hlcdc_pwm_resume); 214 215 static const struct of_device_id atmel_hlcdc_dt_ids[] = { 216 { 217 .compatible = "atmel,at91sam9n12-hlcdc", 218 /* 9n12 has same errata as 9x5 HLCDC PWM */ 219 .data = &atmel_hlcdc_pwm_at91sam9x5_errata, 220 }, 221 { 222 .compatible = "atmel,at91sam9x5-hlcdc", 223 .data = &atmel_hlcdc_pwm_at91sam9x5_errata, 224 }, 225 { 226 .compatible = "atmel,sama5d2-hlcdc", 227 }, 228 { 229 .compatible = "atmel,sama5d3-hlcdc", 230 .data = &atmel_hlcdc_pwm_sama5d3_errata, 231 }, 232 { 233 .compatible = "atmel,sama5d4-hlcdc", 234 .data = &atmel_hlcdc_pwm_sama5d3_errata, 235 }, 236 { .compatible = "microchip,sam9x60-hlcdc", }, 237 { /* sentinel */ }, 238 }; 239 MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids); 240 241 static int atmel_hlcdc_pwm_probe(struct platform_device *pdev) 242 { 243 const struct of_device_id *match; 244 struct device *dev = &pdev->dev; 245 struct pwm_chip *chip; 246 struct atmel_hlcdc_pwm *atmel; 247 struct atmel_hlcdc *hlcdc; 248 int ret; 249 250 hlcdc = dev_get_drvdata(dev->parent); 251 252 chip = devm_pwmchip_alloc(dev, 1, sizeof(*atmel)); 253 if (IS_ERR(chip)) 254 return PTR_ERR(chip); 255 atmel = to_atmel_hlcdc_pwm(chip); 256 257 ret = clk_prepare_enable(hlcdc->periph_clk); 258 if (ret) 259 return ret; 260 261 match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node); 262 if (match) 263 atmel->errata = match->data; 264 265 atmel->hlcdc = hlcdc; 266 chip->ops = &atmel_hlcdc_pwm_ops; 267 268 ret = pwmchip_add(chip); 269 if (ret) { 270 clk_disable_unprepare(hlcdc->periph_clk); 271 return ret; 272 } 273 274 platform_set_drvdata(pdev, chip); 275 276 return 0; 277 } 278 279 static void atmel_hlcdc_pwm_remove(struct platform_device *pdev) 280 { 281 struct pwm_chip *chip = platform_get_drvdata(pdev); 282 struct atmel_hlcdc_pwm *atmel = to_atmel_hlcdc_pwm(chip); 283 284 pwmchip_remove(chip); 285 286 clk_disable_unprepare(atmel->hlcdc->periph_clk); 287 } 288 289 static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = { 290 { .compatible = "atmel,hlcdc-pwm" }, 291 { /* sentinel */ }, 292 }; 293 294 static struct platform_driver atmel_hlcdc_pwm_driver = { 295 .driver = { 296 .name = "atmel-hlcdc-pwm", 297 .of_match_table = atmel_hlcdc_pwm_dt_ids, 298 .pm = pm_ptr(&atmel_hlcdc_pwm_pm_ops), 299 }, 300 .probe = atmel_hlcdc_pwm_probe, 301 .remove_new = atmel_hlcdc_pwm_remove, 302 }; 303 module_platform_driver(atmel_hlcdc_pwm_driver); 304 305 MODULE_ALIAS("platform:atmel-hlcdc-pwm"); 306 MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>"); 307 MODULE_DESCRIPTION("Atmel HLCDC PWM driver"); 308 MODULE_LICENSE("GPL v2"); 309