1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Imagination Technologies Pulse Width Modulator driver 4 * 5 * Copyright (c) 2014-2015, Imagination Technologies 6 * 7 * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation 8 */ 9 10 #include <linux/clk.h> 11 #include <linux/err.h> 12 #include <linux/io.h> 13 #include <linux/mfd/syscon.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 #include <linux/platform_device.h> 17 #include <linux/pm_runtime.h> 18 #include <linux/property.h> 19 #include <linux/pwm.h> 20 #include <linux/regmap.h> 21 #include <linux/slab.h> 22 23 /* PWM registers */ 24 #define PWM_CTRL_CFG 0x0000 25 #define PWM_CTRL_CFG_NO_SUB_DIV 0 26 #define PWM_CTRL_CFG_SUB_DIV0 1 27 #define PWM_CTRL_CFG_SUB_DIV1 2 28 #define PWM_CTRL_CFG_SUB_DIV0_DIV1 3 29 #define PWM_CTRL_CFG_DIV_SHIFT(ch) ((ch) * 2 + 4) 30 #define PWM_CTRL_CFG_DIV_MASK 0x3 31 32 #define PWM_CH_CFG(ch) (0x4 + (ch) * 4) 33 #define PWM_CH_CFG_TMBASE_SHIFT 0 34 #define PWM_CH_CFG_DUTY_SHIFT 16 35 36 #define PERIP_PWM_PDM_CONTROL 0x0140 37 #define PERIP_PWM_PDM_CONTROL_CH_MASK 0x1 38 #define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch) ((ch) * 4) 39 40 #define IMG_PWM_PM_TIMEOUT 1000 /* ms */ 41 42 /* 43 * PWM period is specified with a timebase register, 44 * in number of step periods. The PWM duty cycle is also 45 * specified in step periods, in the [0, $timebase] range. 46 * In other words, the timebase imposes the duty cycle 47 * resolution. Therefore, let's constraint the timebase to 48 * a minimum value to allow a sane range of duty cycle values. 49 * Imposing a minimum timebase, will impose a maximum PWM frequency. 50 * 51 * The value chosen is completely arbitrary. 52 */ 53 #define MIN_TMBASE_STEPS 16 54 55 #define IMG_PWM_NPWM 4 56 57 struct img_pwm_soc_data { 58 u32 max_timebase; 59 }; 60 61 struct img_pwm_chip { 62 struct clk *pwm_clk; 63 struct clk *sys_clk; 64 void __iomem *base; 65 struct regmap *periph_regs; 66 int max_period_ns; 67 int min_period_ns; 68 const struct img_pwm_soc_data *data; 69 u32 suspend_ctrl_cfg; 70 u32 suspend_ch_cfg[IMG_PWM_NPWM]; 71 }; 72 73 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip) 74 { 75 return pwmchip_get_drvdata(chip); 76 } 77 78 static inline void img_pwm_writel(struct img_pwm_chip *imgchip, 79 u32 reg, u32 val) 80 { 81 writel(val, imgchip->base + reg); 82 } 83 84 static inline u32 img_pwm_readl(struct img_pwm_chip *imgchip, u32 reg) 85 { 86 return readl(imgchip->base + reg); 87 } 88 89 static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 90 int duty_ns, int period_ns) 91 { 92 u32 val, div, duty, timebase; 93 unsigned long mul, output_clk_hz, input_clk_hz; 94 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 95 unsigned int max_timebase = imgchip->data->max_timebase; 96 int ret; 97 98 if (period_ns < imgchip->min_period_ns || 99 period_ns > imgchip->max_period_ns) { 100 dev_err(pwmchip_parent(chip), "configured period not in range\n"); 101 return -ERANGE; 102 } 103 104 input_clk_hz = clk_get_rate(imgchip->pwm_clk); 105 output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns); 106 107 mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz); 108 if (mul <= max_timebase) { 109 div = PWM_CTRL_CFG_NO_SUB_DIV; 110 timebase = DIV_ROUND_UP(mul, 1); 111 } else if (mul <= max_timebase * 8) { 112 div = PWM_CTRL_CFG_SUB_DIV0; 113 timebase = DIV_ROUND_UP(mul, 8); 114 } else if (mul <= max_timebase * 64) { 115 div = PWM_CTRL_CFG_SUB_DIV1; 116 timebase = DIV_ROUND_UP(mul, 64); 117 } else if (mul <= max_timebase * 512) { 118 div = PWM_CTRL_CFG_SUB_DIV0_DIV1; 119 timebase = DIV_ROUND_UP(mul, 512); 120 } else { 121 dev_err(pwmchip_parent(chip), 122 "failed to configure timebase steps/divider value\n"); 123 return -EINVAL; 124 } 125 126 duty = DIV_ROUND_UP(timebase * duty_ns, period_ns); 127 128 ret = pm_runtime_resume_and_get(pwmchip_parent(chip)); 129 if (ret < 0) 130 return ret; 131 132 val = img_pwm_readl(imgchip, PWM_CTRL_CFG); 133 val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm)); 134 val |= (div & PWM_CTRL_CFG_DIV_MASK) << 135 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm); 136 img_pwm_writel(imgchip, PWM_CTRL_CFG, val); 137 138 val = (duty << PWM_CH_CFG_DUTY_SHIFT) | 139 (timebase << PWM_CH_CFG_TMBASE_SHIFT); 140 img_pwm_writel(imgchip, PWM_CH_CFG(pwm->hwpwm), val); 141 142 pm_runtime_mark_last_busy(pwmchip_parent(chip)); 143 pm_runtime_put_autosuspend(pwmchip_parent(chip)); 144 145 return 0; 146 } 147 148 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 149 { 150 u32 val; 151 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 152 int ret; 153 154 ret = pm_runtime_resume_and_get(pwmchip_parent(chip)); 155 if (ret < 0) 156 return ret; 157 158 val = img_pwm_readl(imgchip, PWM_CTRL_CFG); 159 val |= BIT(pwm->hwpwm); 160 img_pwm_writel(imgchip, PWM_CTRL_CFG, val); 161 162 regmap_clear_bits(imgchip->periph_regs, PERIP_PWM_PDM_CONTROL, 163 PERIP_PWM_PDM_CONTROL_CH_MASK << 164 PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm)); 165 166 return 0; 167 } 168 169 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 170 { 171 u32 val; 172 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 173 174 val = img_pwm_readl(imgchip, PWM_CTRL_CFG); 175 val &= ~BIT(pwm->hwpwm); 176 img_pwm_writel(imgchip, PWM_CTRL_CFG, val); 177 178 pm_runtime_mark_last_busy(pwmchip_parent(chip)); 179 pm_runtime_put_autosuspend(pwmchip_parent(chip)); 180 } 181 182 static int img_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 183 const struct pwm_state *state) 184 { 185 int err; 186 187 if (state->polarity != PWM_POLARITY_NORMAL) 188 return -EINVAL; 189 190 if (!state->enabled) { 191 if (pwm->state.enabled) 192 img_pwm_disable(chip, pwm); 193 194 return 0; 195 } 196 197 err = img_pwm_config(chip, pwm, state->duty_cycle, state->period); 198 if (err) 199 return err; 200 201 if (!pwm->state.enabled) 202 err = img_pwm_enable(chip, pwm); 203 204 return err; 205 } 206 207 static const struct pwm_ops img_pwm_ops = { 208 .apply = img_pwm_apply, 209 }; 210 211 static const struct img_pwm_soc_data pistachio_pwm = { 212 .max_timebase = 255, 213 }; 214 215 static const struct of_device_id img_pwm_of_match[] = { 216 { 217 .compatible = "img,pistachio-pwm", 218 .data = &pistachio_pwm, 219 }, 220 { } 221 }; 222 MODULE_DEVICE_TABLE(of, img_pwm_of_match); 223 224 static int img_pwm_runtime_suspend(struct device *dev) 225 { 226 struct pwm_chip *chip = dev_get_drvdata(dev); 227 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 228 229 clk_disable_unprepare(imgchip->pwm_clk); 230 clk_disable_unprepare(imgchip->sys_clk); 231 232 return 0; 233 } 234 235 static int img_pwm_runtime_resume(struct device *dev) 236 { 237 struct pwm_chip *chip = dev_get_drvdata(dev); 238 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 239 int ret; 240 241 ret = clk_prepare_enable(imgchip->sys_clk); 242 if (ret < 0) { 243 dev_err(dev, "could not prepare or enable sys clock\n"); 244 return ret; 245 } 246 247 ret = clk_prepare_enable(imgchip->pwm_clk); 248 if (ret < 0) { 249 dev_err(dev, "could not prepare or enable pwm clock\n"); 250 clk_disable_unprepare(imgchip->sys_clk); 251 return ret; 252 } 253 254 return 0; 255 } 256 257 static int img_pwm_probe(struct platform_device *pdev) 258 { 259 int ret; 260 u64 val; 261 unsigned long clk_rate; 262 struct pwm_chip *chip; 263 struct img_pwm_chip *imgchip; 264 265 chip = devm_pwmchip_alloc(&pdev->dev, IMG_PWM_NPWM, sizeof(*imgchip)); 266 if (IS_ERR(chip)) 267 return PTR_ERR(chip); 268 imgchip = to_img_pwm_chip(chip); 269 270 imgchip->base = devm_platform_ioremap_resource(pdev, 0); 271 if (IS_ERR(imgchip->base)) 272 return PTR_ERR(imgchip->base); 273 274 imgchip->data = device_get_match_data(&pdev->dev); 275 276 imgchip->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, 277 "img,cr-periph"); 278 if (IS_ERR(imgchip->periph_regs)) 279 return PTR_ERR(imgchip->periph_regs); 280 281 imgchip->sys_clk = devm_clk_get(&pdev->dev, "sys"); 282 if (IS_ERR(imgchip->sys_clk)) { 283 dev_err(&pdev->dev, "failed to get system clock\n"); 284 return PTR_ERR(imgchip->sys_clk); 285 } 286 287 imgchip->pwm_clk = devm_clk_get(&pdev->dev, "pwm"); 288 if (IS_ERR(imgchip->pwm_clk)) { 289 dev_err(&pdev->dev, "failed to get pwm clock\n"); 290 return PTR_ERR(imgchip->pwm_clk); 291 } 292 293 platform_set_drvdata(pdev, chip); 294 295 pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT); 296 pm_runtime_use_autosuspend(&pdev->dev); 297 pm_runtime_enable(&pdev->dev); 298 if (!pm_runtime_enabled(&pdev->dev)) { 299 ret = img_pwm_runtime_resume(&pdev->dev); 300 if (ret) 301 goto err_pm_disable; 302 } 303 304 clk_rate = clk_get_rate(imgchip->pwm_clk); 305 if (!clk_rate) { 306 dev_err(&pdev->dev, "imgchip clock has no frequency\n"); 307 ret = -EINVAL; 308 goto err_suspend; 309 } 310 311 /* The maximum input clock divider is 512 */ 312 val = (u64)NSEC_PER_SEC * 512 * imgchip->data->max_timebase; 313 do_div(val, clk_rate); 314 imgchip->max_period_ns = val; 315 316 val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS; 317 do_div(val, clk_rate); 318 imgchip->min_period_ns = val; 319 320 chip->ops = &img_pwm_ops; 321 322 ret = pwmchip_add(chip); 323 if (ret < 0) { 324 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret); 325 goto err_suspend; 326 } 327 328 return 0; 329 330 err_suspend: 331 if (!pm_runtime_enabled(&pdev->dev)) 332 img_pwm_runtime_suspend(&pdev->dev); 333 err_pm_disable: 334 pm_runtime_disable(&pdev->dev); 335 pm_runtime_dont_use_autosuspend(&pdev->dev); 336 return ret; 337 } 338 339 static void img_pwm_remove(struct platform_device *pdev) 340 { 341 struct pwm_chip *chip = platform_get_drvdata(pdev); 342 343 pm_runtime_disable(&pdev->dev); 344 if (!pm_runtime_status_suspended(&pdev->dev)) 345 img_pwm_runtime_suspend(&pdev->dev); 346 347 pwmchip_remove(chip); 348 } 349 350 #ifdef CONFIG_PM_SLEEP 351 static int img_pwm_suspend(struct device *dev) 352 { 353 struct pwm_chip *chip = dev_get_drvdata(dev); 354 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 355 int i, ret; 356 357 if (pm_runtime_status_suspended(dev)) { 358 ret = img_pwm_runtime_resume(dev); 359 if (ret) 360 return ret; 361 } 362 363 for (i = 0; i < chip->npwm; i++) 364 imgchip->suspend_ch_cfg[i] = img_pwm_readl(imgchip, 365 PWM_CH_CFG(i)); 366 367 imgchip->suspend_ctrl_cfg = img_pwm_readl(imgchip, PWM_CTRL_CFG); 368 369 img_pwm_runtime_suspend(dev); 370 371 return 0; 372 } 373 374 static int img_pwm_resume(struct device *dev) 375 { 376 struct pwm_chip *chip = dev_get_drvdata(dev); 377 struct img_pwm_chip *imgchip = to_img_pwm_chip(chip); 378 int ret; 379 int i; 380 381 ret = img_pwm_runtime_resume(dev); 382 if (ret) 383 return ret; 384 385 for (i = 0; i < chip->npwm; i++) 386 img_pwm_writel(imgchip, PWM_CH_CFG(i), 387 imgchip->suspend_ch_cfg[i]); 388 389 img_pwm_writel(imgchip, PWM_CTRL_CFG, imgchip->suspend_ctrl_cfg); 390 391 for (i = 0; i < chip->npwm; i++) 392 if (imgchip->suspend_ctrl_cfg & BIT(i)) 393 regmap_clear_bits(imgchip->periph_regs, 394 PERIP_PWM_PDM_CONTROL, 395 PERIP_PWM_PDM_CONTROL_CH_MASK << 396 PERIP_PWM_PDM_CONTROL_CH_SHIFT(i)); 397 398 if (pm_runtime_status_suspended(dev)) 399 img_pwm_runtime_suspend(dev); 400 401 return 0; 402 } 403 #endif /* CONFIG_PM */ 404 405 static const struct dev_pm_ops img_pwm_pm_ops = { 406 SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend, 407 img_pwm_runtime_resume, 408 NULL) 409 SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume) 410 }; 411 412 static struct platform_driver img_pwm_driver = { 413 .driver = { 414 .name = "img-pwm", 415 .pm = &img_pwm_pm_ops, 416 .of_match_table = img_pwm_of_match, 417 }, 418 .probe = img_pwm_probe, 419 .remove = img_pwm_remove, 420 }; 421 module_platform_driver(img_pwm_driver); 422 423 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>"); 424 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver"); 425 MODULE_LICENSE("GPL v2"); 426