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/of_device.h> 17 #include <linux/platform_device.h> 18 #include <linux/pm_runtime.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 device *dev; 63 struct pwm_chip chip; 64 struct clk *pwm_clk; 65 struct clk *sys_clk; 66 void __iomem *base; 67 struct regmap *periph_regs; 68 int max_period_ns; 69 int min_period_ns; 70 const struct img_pwm_soc_data *data; 71 u32 suspend_ctrl_cfg; 72 u32 suspend_ch_cfg[IMG_PWM_NPWM]; 73 }; 74 to_img_pwm_chip(struct pwm_chip * chip)75 static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip) 76 { 77 return container_of(chip, struct img_pwm_chip, chip); 78 } 79 img_pwm_writel(struct img_pwm_chip * chip,u32 reg,u32 val)80 static inline void img_pwm_writel(struct img_pwm_chip *chip, 81 u32 reg, u32 val) 82 { 83 writel(val, chip->base + reg); 84 } 85 img_pwm_readl(struct img_pwm_chip * chip,u32 reg)86 static inline u32 img_pwm_readl(struct img_pwm_chip *chip, 87 u32 reg) 88 { 89 return readl(chip->base + reg); 90 } 91 img_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)92 static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 93 int duty_ns, int period_ns) 94 { 95 u32 val, div, duty, timebase; 96 unsigned long mul, output_clk_hz, input_clk_hz; 97 struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip); 98 unsigned int max_timebase = pwm_chip->data->max_timebase; 99 int ret; 100 101 if (period_ns < pwm_chip->min_period_ns || 102 period_ns > pwm_chip->max_period_ns) { 103 dev_err(chip->dev, "configured period not in range\n"); 104 return -ERANGE; 105 } 106 107 input_clk_hz = clk_get_rate(pwm_chip->pwm_clk); 108 output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns); 109 110 mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz); 111 if (mul <= max_timebase) { 112 div = PWM_CTRL_CFG_NO_SUB_DIV; 113 timebase = DIV_ROUND_UP(mul, 1); 114 } else if (mul <= max_timebase * 8) { 115 div = PWM_CTRL_CFG_SUB_DIV0; 116 timebase = DIV_ROUND_UP(mul, 8); 117 } else if (mul <= max_timebase * 64) { 118 div = PWM_CTRL_CFG_SUB_DIV1; 119 timebase = DIV_ROUND_UP(mul, 64); 120 } else if (mul <= max_timebase * 512) { 121 div = PWM_CTRL_CFG_SUB_DIV0_DIV1; 122 timebase = DIV_ROUND_UP(mul, 512); 123 } else { 124 dev_err(chip->dev, 125 "failed to configure timebase steps/divider value\n"); 126 return -EINVAL; 127 } 128 129 duty = DIV_ROUND_UP(timebase * duty_ns, period_ns); 130 131 ret = pm_runtime_get_sync(chip->dev); 132 if (ret < 0) { 133 pm_runtime_put_autosuspend(chip->dev); 134 return ret; 135 } 136 137 val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG); 138 val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm)); 139 val |= (div & PWM_CTRL_CFG_DIV_MASK) << 140 PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm); 141 img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val); 142 143 val = (duty << PWM_CH_CFG_DUTY_SHIFT) | 144 (timebase << PWM_CH_CFG_TMBASE_SHIFT); 145 img_pwm_writel(pwm_chip, PWM_CH_CFG(pwm->hwpwm), val); 146 147 pm_runtime_mark_last_busy(chip->dev); 148 pm_runtime_put_autosuspend(chip->dev); 149 150 return 0; 151 } 152 img_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)153 static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 154 { 155 u32 val; 156 struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip); 157 int ret; 158 159 ret = pm_runtime_resume_and_get(chip->dev); 160 if (ret < 0) 161 return ret; 162 163 val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG); 164 val |= BIT(pwm->hwpwm); 165 img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val); 166 167 regmap_update_bits(pwm_chip->periph_regs, PERIP_PWM_PDM_CONTROL, 168 PERIP_PWM_PDM_CONTROL_CH_MASK << 169 PERIP_PWM_PDM_CONTROL_CH_SHIFT(pwm->hwpwm), 0); 170 171 return 0; 172 } 173 img_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)174 static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 175 { 176 u32 val; 177 struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip); 178 179 val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG); 180 val &= ~BIT(pwm->hwpwm); 181 img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val); 182 183 pm_runtime_mark_last_busy(chip->dev); 184 pm_runtime_put_autosuspend(chip->dev); 185 } 186 187 static const struct pwm_ops img_pwm_ops = { 188 .config = img_pwm_config, 189 .enable = img_pwm_enable, 190 .disable = img_pwm_disable, 191 .owner = THIS_MODULE, 192 }; 193 194 static const struct img_pwm_soc_data pistachio_pwm = { 195 .max_timebase = 255, 196 }; 197 198 static const struct of_device_id img_pwm_of_match[] = { 199 { 200 .compatible = "img,pistachio-pwm", 201 .data = &pistachio_pwm, 202 }, 203 { } 204 }; 205 MODULE_DEVICE_TABLE(of, img_pwm_of_match); 206 img_pwm_runtime_suspend(struct device * dev)207 static int img_pwm_runtime_suspend(struct device *dev) 208 { 209 struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev); 210 211 clk_disable_unprepare(pwm_chip->pwm_clk); 212 clk_disable_unprepare(pwm_chip->sys_clk); 213 214 return 0; 215 } 216 img_pwm_runtime_resume(struct device * dev)217 static int img_pwm_runtime_resume(struct device *dev) 218 { 219 struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev); 220 int ret; 221 222 ret = clk_prepare_enable(pwm_chip->sys_clk); 223 if (ret < 0) { 224 dev_err(dev, "could not prepare or enable sys clock\n"); 225 return ret; 226 } 227 228 ret = clk_prepare_enable(pwm_chip->pwm_clk); 229 if (ret < 0) { 230 dev_err(dev, "could not prepare or enable pwm clock\n"); 231 clk_disable_unprepare(pwm_chip->sys_clk); 232 return ret; 233 } 234 235 return 0; 236 } 237 img_pwm_probe(struct platform_device * pdev)238 static int img_pwm_probe(struct platform_device *pdev) 239 { 240 int ret; 241 u64 val; 242 unsigned long clk_rate; 243 struct resource *res; 244 struct img_pwm_chip *pwm; 245 const struct of_device_id *of_dev_id; 246 247 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); 248 if (!pwm) 249 return -ENOMEM; 250 251 pwm->dev = &pdev->dev; 252 253 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 254 pwm->base = devm_ioremap_resource(&pdev->dev, res); 255 if (IS_ERR(pwm->base)) 256 return PTR_ERR(pwm->base); 257 258 of_dev_id = of_match_device(img_pwm_of_match, &pdev->dev); 259 if (!of_dev_id) 260 return -ENODEV; 261 pwm->data = of_dev_id->data; 262 263 pwm->periph_regs = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, 264 "img,cr-periph"); 265 if (IS_ERR(pwm->periph_regs)) 266 return PTR_ERR(pwm->periph_regs); 267 268 pwm->sys_clk = devm_clk_get(&pdev->dev, "sys"); 269 if (IS_ERR(pwm->sys_clk)) { 270 dev_err(&pdev->dev, "failed to get system clock\n"); 271 return PTR_ERR(pwm->sys_clk); 272 } 273 274 pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm"); 275 if (IS_ERR(pwm->pwm_clk)) { 276 dev_err(&pdev->dev, "failed to get pwm clock\n"); 277 return PTR_ERR(pwm->pwm_clk); 278 } 279 280 platform_set_drvdata(pdev, pwm); 281 282 pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT); 283 pm_runtime_use_autosuspend(&pdev->dev); 284 pm_runtime_enable(&pdev->dev); 285 if (!pm_runtime_enabled(&pdev->dev)) { 286 ret = img_pwm_runtime_resume(&pdev->dev); 287 if (ret) 288 goto err_pm_disable; 289 } 290 291 clk_rate = clk_get_rate(pwm->pwm_clk); 292 if (!clk_rate) { 293 dev_err(&pdev->dev, "pwm clock has no frequency\n"); 294 ret = -EINVAL; 295 goto err_suspend; 296 } 297 298 /* The maximum input clock divider is 512 */ 299 val = (u64)NSEC_PER_SEC * 512 * pwm->data->max_timebase; 300 do_div(val, clk_rate); 301 pwm->max_period_ns = val; 302 303 val = (u64)NSEC_PER_SEC * MIN_TMBASE_STEPS; 304 do_div(val, clk_rate); 305 pwm->min_period_ns = val; 306 307 pwm->chip.dev = &pdev->dev; 308 pwm->chip.ops = &img_pwm_ops; 309 pwm->chip.base = -1; 310 pwm->chip.npwm = IMG_PWM_NPWM; 311 312 ret = pwmchip_add(&pwm->chip); 313 if (ret < 0) { 314 dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret); 315 goto err_suspend; 316 } 317 318 return 0; 319 320 err_suspend: 321 if (!pm_runtime_enabled(&pdev->dev)) 322 img_pwm_runtime_suspend(&pdev->dev); 323 err_pm_disable: 324 pm_runtime_disable(&pdev->dev); 325 pm_runtime_dont_use_autosuspend(&pdev->dev); 326 return ret; 327 } 328 img_pwm_remove(struct platform_device * pdev)329 static int img_pwm_remove(struct platform_device *pdev) 330 { 331 struct img_pwm_chip *pwm_chip = platform_get_drvdata(pdev); 332 333 pm_runtime_disable(&pdev->dev); 334 if (!pm_runtime_status_suspended(&pdev->dev)) 335 img_pwm_runtime_suspend(&pdev->dev); 336 337 return pwmchip_remove(&pwm_chip->chip); 338 } 339 340 #ifdef CONFIG_PM_SLEEP img_pwm_suspend(struct device * dev)341 static int img_pwm_suspend(struct device *dev) 342 { 343 struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev); 344 int i, ret; 345 346 if (pm_runtime_status_suspended(dev)) { 347 ret = img_pwm_runtime_resume(dev); 348 if (ret) 349 return ret; 350 } 351 352 for (i = 0; i < pwm_chip->chip.npwm; i++) 353 pwm_chip->suspend_ch_cfg[i] = img_pwm_readl(pwm_chip, 354 PWM_CH_CFG(i)); 355 356 pwm_chip->suspend_ctrl_cfg = img_pwm_readl(pwm_chip, PWM_CTRL_CFG); 357 358 img_pwm_runtime_suspend(dev); 359 360 return 0; 361 } 362 img_pwm_resume(struct device * dev)363 static int img_pwm_resume(struct device *dev) 364 { 365 struct img_pwm_chip *pwm_chip = dev_get_drvdata(dev); 366 int ret; 367 int i; 368 369 ret = img_pwm_runtime_resume(dev); 370 if (ret) 371 return ret; 372 373 for (i = 0; i < pwm_chip->chip.npwm; i++) 374 img_pwm_writel(pwm_chip, PWM_CH_CFG(i), 375 pwm_chip->suspend_ch_cfg[i]); 376 377 img_pwm_writel(pwm_chip, PWM_CTRL_CFG, pwm_chip->suspend_ctrl_cfg); 378 379 for (i = 0; i < pwm_chip->chip.npwm; i++) 380 if (pwm_chip->suspend_ctrl_cfg & BIT(i)) 381 regmap_update_bits(pwm_chip->periph_regs, 382 PERIP_PWM_PDM_CONTROL, 383 PERIP_PWM_PDM_CONTROL_CH_MASK << 384 PERIP_PWM_PDM_CONTROL_CH_SHIFT(i), 385 0); 386 387 if (pm_runtime_status_suspended(dev)) 388 img_pwm_runtime_suspend(dev); 389 390 return 0; 391 } 392 #endif /* CONFIG_PM */ 393 394 static const struct dev_pm_ops img_pwm_pm_ops = { 395 SET_RUNTIME_PM_OPS(img_pwm_runtime_suspend, 396 img_pwm_runtime_resume, 397 NULL) 398 SET_SYSTEM_SLEEP_PM_OPS(img_pwm_suspend, img_pwm_resume) 399 }; 400 401 static struct platform_driver img_pwm_driver = { 402 .driver = { 403 .name = "img-pwm", 404 .pm = &img_pwm_pm_ops, 405 .of_match_table = img_pwm_of_match, 406 }, 407 .probe = img_pwm_probe, 408 .remove = img_pwm_remove, 409 }; 410 module_platform_driver(img_pwm_driver); 411 412 MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>"); 413 MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver"); 414 MODULE_LICENSE("GPL v2"); 415