1 /* 2 * Driver for Allwinner sun4i Pulse Width Modulation Controller 3 * 4 * Copyright (C) 2014 Alexandre Belloni <alexandre.belloni@free-electrons.com> 5 * 6 * Licensed under GPLv2. 7 */ 8 9 #include <linux/bitops.h> 10 #include <linux/clk.h> 11 #include <linux/err.h> 12 #include <linux/io.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/of_device.h> 16 #include <linux/platform_device.h> 17 #include <linux/pwm.h> 18 #include <linux/slab.h> 19 #include <linux/spinlock.h> 20 #include <linux/time.h> 21 22 #define PWM_CTRL_REG 0x0 23 24 #define PWM_CH_PRD_BASE 0x4 25 #define PWM_CH_PRD_OFFSET 0x4 26 #define PWM_CH_PRD(ch) (PWM_CH_PRD_BASE + PWM_CH_PRD_OFFSET * (ch)) 27 28 #define PWMCH_OFFSET 15 29 #define PWM_PRESCAL_MASK GENMASK(3, 0) 30 #define PWM_PRESCAL_OFF 0 31 #define PWM_EN BIT(4) 32 #define PWM_ACT_STATE BIT(5) 33 #define PWM_CLK_GATING BIT(6) 34 #define PWM_MODE BIT(7) 35 #define PWM_PULSE BIT(8) 36 #define PWM_BYPASS BIT(9) 37 38 #define PWM_RDY_BASE 28 39 #define PWM_RDY_OFFSET 1 40 #define PWM_RDY(ch) BIT(PWM_RDY_BASE + PWM_RDY_OFFSET * (ch)) 41 42 #define PWM_PRD(prd) (((prd) - 1) << 16) 43 #define PWM_PRD_MASK GENMASK(15, 0) 44 45 #define PWM_DTY_MASK GENMASK(15, 0) 46 47 #define BIT_CH(bit, chan) ((bit) << ((chan) * PWMCH_OFFSET)) 48 49 static const u32 prescaler_table[] = { 50 120, 51 180, 52 240, 53 360, 54 480, 55 0, 56 0, 57 0, 58 12000, 59 24000, 60 36000, 61 48000, 62 72000, 63 0, 64 0, 65 0, /* Actually 1 but tested separately */ 66 }; 67 68 struct sun4i_pwm_data { 69 bool has_prescaler_bypass; 70 bool has_rdy; 71 unsigned int npwm; 72 }; 73 74 struct sun4i_pwm_chip { 75 struct pwm_chip chip; 76 struct clk *clk; 77 void __iomem *base; 78 spinlock_t ctrl_lock; 79 const struct sun4i_pwm_data *data; 80 }; 81 82 static inline struct sun4i_pwm_chip *to_sun4i_pwm_chip(struct pwm_chip *chip) 83 { 84 return container_of(chip, struct sun4i_pwm_chip, chip); 85 } 86 87 static inline u32 sun4i_pwm_readl(struct sun4i_pwm_chip *chip, 88 unsigned long offset) 89 { 90 return readl(chip->base + offset); 91 } 92 93 static inline void sun4i_pwm_writel(struct sun4i_pwm_chip *chip, 94 u32 val, unsigned long offset) 95 { 96 writel(val, chip->base + offset); 97 } 98 99 static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 100 int duty_ns, int period_ns) 101 { 102 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); 103 u32 prd, dty, val, clk_gate; 104 u64 clk_rate, div = 0; 105 unsigned int prescaler = 0; 106 int err; 107 108 clk_rate = clk_get_rate(sun4i_pwm->clk); 109 110 if (sun4i_pwm->data->has_prescaler_bypass) { 111 /* First, test without any prescaler when available */ 112 prescaler = PWM_PRESCAL_MASK; 113 /* 114 * When not using any prescaler, the clock period in nanoseconds 115 * is not an integer so round it half up instead of 116 * truncating to get less surprising values. 117 */ 118 div = clk_rate * period_ns + NSEC_PER_SEC / 2; 119 do_div(div, NSEC_PER_SEC); 120 if (div - 1 > PWM_PRD_MASK) 121 prescaler = 0; 122 } 123 124 if (prescaler == 0) { 125 /* Go up from the first divider */ 126 for (prescaler = 0; prescaler < PWM_PRESCAL_MASK; prescaler++) { 127 if (!prescaler_table[prescaler]) 128 continue; 129 div = clk_rate; 130 do_div(div, prescaler_table[prescaler]); 131 div = div * period_ns; 132 do_div(div, NSEC_PER_SEC); 133 if (div - 1 <= PWM_PRD_MASK) 134 break; 135 } 136 137 if (div - 1 > PWM_PRD_MASK) { 138 dev_err(chip->dev, "period exceeds the maximum value\n"); 139 return -EINVAL; 140 } 141 } 142 143 prd = div; 144 div *= duty_ns; 145 do_div(div, period_ns); 146 dty = div; 147 148 err = clk_prepare_enable(sun4i_pwm->clk); 149 if (err) { 150 dev_err(chip->dev, "failed to enable PWM clock\n"); 151 return err; 152 } 153 154 spin_lock(&sun4i_pwm->ctrl_lock); 155 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 156 157 if (sun4i_pwm->data->has_rdy && (val & PWM_RDY(pwm->hwpwm))) { 158 spin_unlock(&sun4i_pwm->ctrl_lock); 159 clk_disable_unprepare(sun4i_pwm->clk); 160 return -EBUSY; 161 } 162 163 clk_gate = val & BIT_CH(PWM_CLK_GATING, pwm->hwpwm); 164 if (clk_gate) { 165 val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); 166 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 167 } 168 169 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 170 val &= ~BIT_CH(PWM_PRESCAL_MASK, pwm->hwpwm); 171 val |= BIT_CH(prescaler, pwm->hwpwm); 172 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 173 174 val = (dty & PWM_DTY_MASK) | PWM_PRD(prd); 175 sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm)); 176 177 if (clk_gate) { 178 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 179 val |= clk_gate; 180 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 181 } 182 183 spin_unlock(&sun4i_pwm->ctrl_lock); 184 clk_disable_unprepare(sun4i_pwm->clk); 185 186 return 0; 187 } 188 189 static int sun4i_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm, 190 enum pwm_polarity polarity) 191 { 192 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); 193 u32 val; 194 int ret; 195 196 ret = clk_prepare_enable(sun4i_pwm->clk); 197 if (ret) { 198 dev_err(chip->dev, "failed to enable PWM clock\n"); 199 return ret; 200 } 201 202 spin_lock(&sun4i_pwm->ctrl_lock); 203 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 204 205 if (polarity != PWM_POLARITY_NORMAL) 206 val &= ~BIT_CH(PWM_ACT_STATE, pwm->hwpwm); 207 else 208 val |= BIT_CH(PWM_ACT_STATE, pwm->hwpwm); 209 210 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 211 212 spin_unlock(&sun4i_pwm->ctrl_lock); 213 clk_disable_unprepare(sun4i_pwm->clk); 214 215 return 0; 216 } 217 218 static int sun4i_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 219 { 220 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); 221 u32 val; 222 int ret; 223 224 ret = clk_prepare_enable(sun4i_pwm->clk); 225 if (ret) { 226 dev_err(chip->dev, "failed to enable PWM clock\n"); 227 return ret; 228 } 229 230 spin_lock(&sun4i_pwm->ctrl_lock); 231 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 232 val |= BIT_CH(PWM_EN, pwm->hwpwm); 233 val |= BIT_CH(PWM_CLK_GATING, pwm->hwpwm); 234 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 235 spin_unlock(&sun4i_pwm->ctrl_lock); 236 237 return 0; 238 } 239 240 static void sun4i_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 241 { 242 struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip); 243 u32 val; 244 245 spin_lock(&sun4i_pwm->ctrl_lock); 246 val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG); 247 val &= ~BIT_CH(PWM_EN, pwm->hwpwm); 248 val &= ~BIT_CH(PWM_CLK_GATING, pwm->hwpwm); 249 sun4i_pwm_writel(sun4i_pwm, val, PWM_CTRL_REG); 250 spin_unlock(&sun4i_pwm->ctrl_lock); 251 252 clk_disable_unprepare(sun4i_pwm->clk); 253 } 254 255 static const struct pwm_ops sun4i_pwm_ops = { 256 .config = sun4i_pwm_config, 257 .set_polarity = sun4i_pwm_set_polarity, 258 .enable = sun4i_pwm_enable, 259 .disable = sun4i_pwm_disable, 260 .owner = THIS_MODULE, 261 }; 262 263 static const struct sun4i_pwm_data sun4i_pwm_data_a10 = { 264 .has_prescaler_bypass = false, 265 .has_rdy = false, 266 .npwm = 2, 267 }; 268 269 static const struct sun4i_pwm_data sun4i_pwm_data_a10s = { 270 .has_prescaler_bypass = true, 271 .has_rdy = true, 272 .npwm = 2, 273 }; 274 275 static const struct sun4i_pwm_data sun4i_pwm_data_a13 = { 276 .has_prescaler_bypass = true, 277 .has_rdy = true, 278 .npwm = 1, 279 }; 280 281 static const struct sun4i_pwm_data sun4i_pwm_data_a20 = { 282 .has_prescaler_bypass = true, 283 .has_rdy = true, 284 .npwm = 2, 285 }; 286 287 static const struct of_device_id sun4i_pwm_dt_ids[] = { 288 { 289 .compatible = "allwinner,sun4i-a10-pwm", 290 .data = &sun4i_pwm_data_a10, 291 }, { 292 .compatible = "allwinner,sun5i-a10s-pwm", 293 .data = &sun4i_pwm_data_a10s, 294 }, { 295 .compatible = "allwinner,sun5i-a13-pwm", 296 .data = &sun4i_pwm_data_a13, 297 }, { 298 .compatible = "allwinner,sun7i-a20-pwm", 299 .data = &sun4i_pwm_data_a20, 300 }, { 301 /* sentinel */ 302 }, 303 }; 304 MODULE_DEVICE_TABLE(of, sun4i_pwm_dt_ids); 305 306 static int sun4i_pwm_probe(struct platform_device *pdev) 307 { 308 struct sun4i_pwm_chip *pwm; 309 struct resource *res; 310 u32 val; 311 int i, ret; 312 const struct of_device_id *match; 313 314 match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev); 315 316 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); 317 if (!pwm) 318 return -ENOMEM; 319 320 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 321 pwm->base = devm_ioremap_resource(&pdev->dev, res); 322 if (IS_ERR(pwm->base)) 323 return PTR_ERR(pwm->base); 324 325 pwm->clk = devm_clk_get(&pdev->dev, NULL); 326 if (IS_ERR(pwm->clk)) 327 return PTR_ERR(pwm->clk); 328 329 pwm->data = match->data; 330 pwm->chip.dev = &pdev->dev; 331 pwm->chip.ops = &sun4i_pwm_ops; 332 pwm->chip.base = -1; 333 pwm->chip.npwm = pwm->data->npwm; 334 pwm->chip.can_sleep = true; 335 pwm->chip.of_xlate = of_pwm_xlate_with_flags; 336 pwm->chip.of_pwm_n_cells = 3; 337 338 spin_lock_init(&pwm->ctrl_lock); 339 340 ret = pwmchip_add(&pwm->chip); 341 if (ret < 0) { 342 dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); 343 return ret; 344 } 345 346 platform_set_drvdata(pdev, pwm); 347 348 ret = clk_prepare_enable(pwm->clk); 349 if (ret) { 350 dev_err(&pdev->dev, "failed to enable PWM clock\n"); 351 goto clk_error; 352 } 353 354 val = sun4i_pwm_readl(pwm, PWM_CTRL_REG); 355 for (i = 0; i < pwm->chip.npwm; i++) 356 if (!(val & BIT_CH(PWM_ACT_STATE, i))) 357 pwm_set_polarity(&pwm->chip.pwms[i], 358 PWM_POLARITY_INVERSED); 359 clk_disable_unprepare(pwm->clk); 360 361 return 0; 362 363 clk_error: 364 pwmchip_remove(&pwm->chip); 365 return ret; 366 } 367 368 static int sun4i_pwm_remove(struct platform_device *pdev) 369 { 370 struct sun4i_pwm_chip *pwm = platform_get_drvdata(pdev); 371 372 return pwmchip_remove(&pwm->chip); 373 } 374 375 static struct platform_driver sun4i_pwm_driver = { 376 .driver = { 377 .name = "sun4i-pwm", 378 .of_match_table = sun4i_pwm_dt_ids, 379 }, 380 .probe = sun4i_pwm_probe, 381 .remove = sun4i_pwm_remove, 382 }; 383 module_platform_driver(sun4i_pwm_driver); 384 385 MODULE_ALIAS("platform:sun4i-pwm"); 386 MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@free-electrons.com>"); 387 MODULE_DESCRIPTION("Allwinner sun4i PWM driver"); 388 MODULE_LICENSE("GPL v2"); 389