1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Driver for TWL4030/6030 Pulse Width Modulator used as LED driver 4 * 5 * Copyright (C) 2012 Texas Instruments 6 * Author: Peter Ujfalusi <peter.ujfalusi@ti.com> 7 * 8 * This driver is a complete rewrite of the former pwm-twl6030.c authorded by: 9 * Hemanth V <hemanthv@ti.com> 10 * 11 * Reference manual for the twl6030 is available at: 12 * https://www.ti.com/lit/ds/symlink/twl6030.pdf 13 * 14 * Limitations: 15 * - The twl6030 hardware only supports two period lengths (128 clock ticks and 16 * 64 clock ticks), the driver only uses 128 ticks 17 * - The hardware doesn't support ON = 0, so the active part of a period doesn't 18 * start at its beginning. 19 * - The hardware could support inverted polarity (with a similar limitation as 20 * for normal: the last clock tick is always inactive). 21 * - The hardware emits a constant low output when disabled. 22 * - A request for .duty_cycle = 0 results in an output wave with one active 23 * clock tick per period. This should better use the disabled state. 24 * - The driver only implements setting the relative duty cycle. 25 * - The driver doesn't implement .get_state(). 26 */ 27 28 #include <linux/module.h> 29 #include <linux/of.h> 30 #include <linux/platform_device.h> 31 #include <linux/pwm.h> 32 #include <linux/mfd/twl.h> 33 #include <linux/slab.h> 34 35 /* 36 * This driver handles the PWM driven LED terminals of TWL4030 and TWL6030. 37 * To generate the signal on TWL4030: 38 * - LEDA uses PWMA 39 * - LEDB uses PWMB 40 * TWL6030 has one LED pin with dedicated LEDPWM 41 */ 42 43 #define TWL4030_LED_MAX 0x7f 44 #define TWL6030_LED_MAX 0xff 45 46 /* Registers, bits and macro for TWL4030 */ 47 #define TWL4030_LEDEN_REG 0x00 48 #define TWL4030_PWMA_REG 0x01 49 50 #define TWL4030_LEDXON (1 << 0) 51 #define TWL4030_LEDXPWM (1 << 4) 52 #define TWL4030_LED_PINS (TWL4030_LEDXON | TWL4030_LEDXPWM) 53 #define TWL4030_LED_TOGGLE(led, x) ((x) << (led)) 54 55 /* Register, bits and macro for TWL6030 */ 56 #define TWL6030_LED_PWM_CTRL1 0xf4 57 #define TWL6030_LED_PWM_CTRL2 0xf5 58 59 #define TWL6040_LED_MODE_HW 0x00 60 #define TWL6040_LED_MODE_ON 0x01 61 #define TWL6040_LED_MODE_OFF 0x02 62 #define TWL6040_LED_MODE_MASK 0x03 63 64 struct twl_pwmled_chip { 65 struct mutex mutex; 66 }; 67 68 static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip) 69 { 70 return pwmchip_get_drvdata(chip); 71 } 72 73 static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm, 74 int duty_ns, int period_ns) 75 { 76 int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1; 77 u8 pwm_config[2] = { 1, 0 }; 78 int base, ret; 79 80 /* 81 * To configure the duty period: 82 * On-cycle is set to 1 (the minimum allowed value) 83 * The off time of 0 is not configurable, so the mapping is: 84 * 0 -> off cycle = 2, 85 * 1 -> off cycle = 2, 86 * 2 -> off cycle = 3, 87 * 126 - > off cycle 127, 88 * 127 - > off cycle 1 89 * When on cycle == off cycle the PWM will be always on 90 */ 91 if (duty_cycle == 1) 92 duty_cycle = 2; 93 else if (duty_cycle > TWL4030_LED_MAX) 94 duty_cycle = 1; 95 96 base = pwm->hwpwm * 2 + TWL4030_PWMA_REG; 97 98 pwm_config[1] = duty_cycle; 99 100 ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2); 101 if (ret < 0) 102 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label); 103 104 return ret; 105 } 106 107 static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm) 108 { 109 struct twl_pwmled_chip *twl = to_twl(chip); 110 int ret; 111 u8 val; 112 113 mutex_lock(&twl->mutex); 114 ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG); 115 if (ret < 0) { 116 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label); 117 goto out; 118 } 119 120 val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS); 121 122 ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG); 123 if (ret < 0) 124 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label); 125 126 out: 127 mutex_unlock(&twl->mutex); 128 return ret; 129 } 130 131 static void twl4030_pwmled_disable(struct pwm_chip *chip, 132 struct pwm_device *pwm) 133 { 134 struct twl_pwmled_chip *twl = to_twl(chip); 135 int ret; 136 u8 val; 137 138 mutex_lock(&twl->mutex); 139 ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG); 140 if (ret < 0) { 141 dev_err(pwmchip_parent(chip), "%s: Failed to read LEDEN\n", pwm->label); 142 goto out; 143 } 144 145 val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS); 146 147 ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG); 148 if (ret < 0) 149 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label); 150 151 out: 152 mutex_unlock(&twl->mutex); 153 } 154 155 static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm, 156 const struct pwm_state *state) 157 { 158 int ret; 159 160 if (state->polarity != PWM_POLARITY_NORMAL) 161 return -EINVAL; 162 163 if (!state->enabled) { 164 if (pwm->state.enabled) 165 twl4030_pwmled_disable(chip, pwm); 166 167 return 0; 168 } 169 170 /* 171 * We cannot skip calling ->config even if state->period == 172 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle 173 * because we might have exited early in the last call to 174 * pwm_apply_might_sleep because of !state->enabled and so the two values in 175 * pwm->state might not be configured in hardware. 176 */ 177 ret = twl4030_pwmled_config(chip, pwm, 178 state->duty_cycle, state->period); 179 if (ret) 180 return ret; 181 182 if (!pwm->state.enabled) 183 ret = twl4030_pwmled_enable(chip, pwm); 184 185 return ret; 186 } 187 188 189 static const struct pwm_ops twl4030_pwmled_ops = { 190 .apply = twl4030_pwmled_apply, 191 }; 192 193 static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm, 194 int duty_ns, int period_ns) 195 { 196 int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns; 197 u8 on_time; 198 int ret; 199 200 on_time = duty_cycle & 0xff; 201 202 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time, 203 TWL6030_LED_PWM_CTRL1); 204 if (ret < 0) 205 dev_err(pwmchip_parent(chip), "%s: Failed to configure PWM\n", pwm->label); 206 207 return ret; 208 } 209 210 static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm) 211 { 212 struct twl_pwmled_chip *twl = to_twl(chip); 213 int ret; 214 u8 val; 215 216 mutex_lock(&twl->mutex); 217 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); 218 if (ret < 0) { 219 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n", 220 pwm->label); 221 goto out; 222 } 223 224 val &= ~TWL6040_LED_MODE_MASK; 225 val |= TWL6040_LED_MODE_ON; 226 227 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); 228 if (ret < 0) 229 dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM\n", pwm->label); 230 231 out: 232 mutex_unlock(&twl->mutex); 233 return ret; 234 } 235 236 static void twl6030_pwmled_disable(struct pwm_chip *chip, 237 struct pwm_device *pwm) 238 { 239 struct twl_pwmled_chip *twl = to_twl(chip); 240 int ret; 241 u8 val; 242 243 mutex_lock(&twl->mutex); 244 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); 245 if (ret < 0) { 246 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n", 247 pwm->label); 248 goto out; 249 } 250 251 val &= ~TWL6040_LED_MODE_MASK; 252 val |= TWL6040_LED_MODE_OFF; 253 254 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); 255 if (ret < 0) 256 dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM\n", pwm->label); 257 258 out: 259 mutex_unlock(&twl->mutex); 260 } 261 262 static int twl6030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm, 263 const struct pwm_state *state) 264 { 265 int err; 266 267 if (state->polarity != pwm->state.polarity) 268 return -EINVAL; 269 270 if (!state->enabled) { 271 if (pwm->state.enabled) 272 twl6030_pwmled_disable(chip, pwm); 273 274 return 0; 275 } 276 277 err = twl6030_pwmled_config(chip, pwm, 278 state->duty_cycle, state->period); 279 if (err) 280 return err; 281 282 if (!pwm->state.enabled) 283 err = twl6030_pwmled_enable(chip, pwm); 284 285 return err; 286 } 287 288 static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm) 289 { 290 struct twl_pwmled_chip *twl = to_twl(chip); 291 int ret; 292 u8 val; 293 294 mutex_lock(&twl->mutex); 295 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); 296 if (ret < 0) { 297 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n", 298 pwm->label); 299 goto out; 300 } 301 302 val &= ~TWL6040_LED_MODE_MASK; 303 val |= TWL6040_LED_MODE_OFF; 304 305 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); 306 if (ret < 0) 307 dev_err(pwmchip_parent(chip), "%s: Failed to request PWM\n", pwm->label); 308 309 out: 310 mutex_unlock(&twl->mutex); 311 return ret; 312 } 313 314 static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm) 315 { 316 struct twl_pwmled_chip *twl = to_twl(chip); 317 int ret; 318 u8 val; 319 320 mutex_lock(&twl->mutex); 321 ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2); 322 if (ret < 0) { 323 dev_err(pwmchip_parent(chip), "%s: Failed to read PWM_CTRL2\n", 324 pwm->label); 325 goto out; 326 } 327 328 val &= ~TWL6040_LED_MODE_MASK; 329 val |= TWL6040_LED_MODE_HW; 330 331 ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2); 332 if (ret < 0) 333 dev_err(pwmchip_parent(chip), "%s: Failed to free PWM\n", pwm->label); 334 335 out: 336 mutex_unlock(&twl->mutex); 337 } 338 339 static const struct pwm_ops twl6030_pwmled_ops = { 340 .apply = twl6030_pwmled_apply, 341 .request = twl6030_pwmled_request, 342 .free = twl6030_pwmled_free, 343 }; 344 345 static int twl_pwmled_probe(struct platform_device *pdev) 346 { 347 struct pwm_chip *chip; 348 struct twl_pwmled_chip *twl; 349 unsigned int npwm; 350 const struct pwm_ops *ops; 351 352 if (twl_class_is_4030()) { 353 ops = &twl4030_pwmled_ops; 354 npwm = 2; 355 } else { 356 ops = &twl6030_pwmled_ops; 357 npwm = 1; 358 } 359 360 chip = devm_pwmchip_alloc(&pdev->dev, npwm, sizeof(*twl)); 361 if (IS_ERR(chip)) 362 return PTR_ERR(chip); 363 twl = to_twl(chip); 364 365 chip->ops = ops; 366 367 mutex_init(&twl->mutex); 368 369 return devm_pwmchip_add(&pdev->dev, chip); 370 } 371 372 #ifdef CONFIG_OF 373 static const struct of_device_id twl_pwmled_of_match[] = { 374 { .compatible = "ti,twl4030-pwmled" }, 375 { .compatible = "ti,twl6030-pwmled" }, 376 { }, 377 }; 378 MODULE_DEVICE_TABLE(of, twl_pwmled_of_match); 379 #endif 380 381 static struct platform_driver twl_pwmled_driver = { 382 .driver = { 383 .name = "twl-pwmled", 384 .of_match_table = of_match_ptr(twl_pwmled_of_match), 385 }, 386 .probe = twl_pwmled_probe, 387 }; 388 module_platform_driver(twl_pwmled_driver); 389 390 MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>"); 391 MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs"); 392 MODULE_ALIAS("platform:twl-pwmled"); 393 MODULE_LICENSE("GPL"); 394