1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * TI/National Semiconductor LP3943 PWM driver 4 * 5 * Copyright 2013 Texas Instruments 6 * 7 * Author: Milo Kim <milo.kim@ti.com> 8 */ 9 10 #include <linux/err.h> 11 #include <linux/mfd/lp3943.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/slab.h> 17 18 #define LP3943_MAX_DUTY 255 19 #define LP3943_MIN_PERIOD 6250 20 #define LP3943_MAX_PERIOD 1600000 21 22 struct lp3943_pwm { 23 struct pwm_chip chip; 24 struct lp3943 *lp3943; 25 struct lp3943_platform_data *pdata; 26 }; 27 28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip) 29 { 30 return container_of(chip, struct lp3943_pwm, chip); 31 } 32 33 static struct lp3943_pwm_map * 34 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm) 35 { 36 struct lp3943_platform_data *pdata = lp3943_pwm->pdata; 37 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 38 struct lp3943_pwm_map *pwm_map; 39 int i, offset; 40 41 pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL); 42 if (!pwm_map) 43 return ERR_PTR(-ENOMEM); 44 45 pwm_map->output = pdata->pwms[hwpwm]->output; 46 pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs; 47 48 for (i = 0; i < pwm_map->num_outputs; i++) { 49 offset = pwm_map->output[i]; 50 51 /* Return an error if the pin is already assigned */ 52 if (test_and_set_bit(offset, &lp3943->pin_used)) { 53 kfree(pwm_map); 54 return ERR_PTR(-EBUSY); 55 } 56 } 57 58 return pwm_map; 59 } 60 61 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 62 { 63 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 64 struct lp3943_pwm_map *pwm_map; 65 66 pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm); 67 if (IS_ERR(pwm_map)) 68 return PTR_ERR(pwm_map); 69 70 return pwm_set_chip_data(pwm, pwm_map); 71 } 72 73 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm, 74 struct lp3943_pwm_map *pwm_map) 75 { 76 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 77 int i, offset; 78 79 for (i = 0; i < pwm_map->num_outputs; i++) { 80 offset = pwm_map->output[i]; 81 clear_bit(offset, &lp3943->pin_used); 82 } 83 84 kfree(pwm_map); 85 } 86 87 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 88 { 89 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 90 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 91 92 lp3943_pwm_free_map(lp3943_pwm, pwm_map); 93 } 94 95 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 96 u64 duty_ns, u64 period_ns) 97 { 98 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 99 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 100 u8 val, reg_duty, reg_prescale; 101 int err; 102 103 /* 104 * How to configure the LP3943 PWMs 105 * 106 * 1) Period = 6250 ~ 1600000 107 * 2) Prescale = period / 6250 -1 108 * 3) Duty = input duty 109 * 110 * Prescale and duty are register values 111 */ 112 113 if (pwm->hwpwm == 0) { 114 reg_prescale = LP3943_REG_PRESCALE0; 115 reg_duty = LP3943_REG_PWM0; 116 } else { 117 reg_prescale = LP3943_REG_PRESCALE1; 118 reg_duty = LP3943_REG_PWM1; 119 } 120 121 /* 122 * Note that after this clamping, period_ns fits into an int. This is 123 * helpful because we can resort to integer division below instead of 124 * the (more expensive) 64 bit division. 125 */ 126 period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD); 127 val = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1); 128 129 err = lp3943_write_byte(lp3943, reg_prescale, val); 130 if (err) 131 return err; 132 133 duty_ns = min(duty_ns, period_ns); 134 val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns); 135 136 return lp3943_write_byte(lp3943, reg_duty, val); 137 } 138 139 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, 140 struct lp3943_pwm_map *pwm_map, 141 u8 val) 142 { 143 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 144 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; 145 int i, index, err; 146 147 for (i = 0; i < pwm_map->num_outputs; i++) { 148 index = pwm_map->output[i]; 149 err = lp3943_update_bits(lp3943, mux[index].reg, 150 mux[index].mask, 151 val << mux[index].shift); 152 if (err) 153 return err; 154 } 155 156 return 0; 157 } 158 159 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 160 { 161 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 162 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 163 u8 val; 164 165 if (pwm->hwpwm == 0) 166 val = LP3943_DIM_PWM0; 167 else 168 val = LP3943_DIM_PWM1; 169 170 /* 171 * Each PWM generator is set to control any of outputs of LP3943. 172 * To enable/disable the PWM, these output pins should be configured. 173 */ 174 175 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); 176 } 177 178 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 179 { 180 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 181 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 182 183 /* 184 * LP3943 outputs are open-drain, so the pin should be configured 185 * when the PWM is disabled. 186 */ 187 188 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); 189 } 190 191 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 192 const struct pwm_state *state) 193 { 194 int err; 195 196 if (state->polarity != PWM_POLARITY_NORMAL) 197 return -EINVAL; 198 199 if (!state->enabled) { 200 if (pwm->state.enabled) 201 lp3943_pwm_disable(chip, pwm); 202 return 0; 203 } 204 205 err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period); 206 if (err) 207 return err; 208 209 if (!pwm->state.enabled) 210 err = lp3943_pwm_enable(chip, pwm); 211 212 return err; 213 } 214 215 static const struct pwm_ops lp3943_pwm_ops = { 216 .request = lp3943_pwm_request, 217 .free = lp3943_pwm_free, 218 .apply = lp3943_pwm_apply, 219 .owner = THIS_MODULE, 220 }; 221 222 static int lp3943_pwm_parse_dt(struct device *dev, 223 struct lp3943_pwm *lp3943_pwm) 224 { 225 static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; 226 struct device_node *node = dev->of_node; 227 struct lp3943_platform_data *pdata; 228 struct lp3943_pwm_map *pwm_map; 229 enum lp3943_pwm_output *output; 230 int i, err, proplen, count = 0; 231 u32 num_outputs; 232 233 if (!node) 234 return -EINVAL; 235 236 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 237 if (!pdata) 238 return -ENOMEM; 239 240 /* 241 * Read the output map configuration from the device tree. 242 * Each of the two PWM generators can drive zero or more outputs. 243 */ 244 245 for (i = 0; i < LP3943_NUM_PWMS; i++) { 246 if (!of_get_property(node, name[i], &proplen)) 247 continue; 248 249 num_outputs = proplen / sizeof(u32); 250 if (num_outputs == 0) 251 continue; 252 253 output = devm_kcalloc(dev, num_outputs, sizeof(*output), 254 GFP_KERNEL); 255 if (!output) 256 return -ENOMEM; 257 258 err = of_property_read_u32_array(node, name[i], output, 259 num_outputs); 260 if (err) 261 return err; 262 263 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); 264 if (!pwm_map) 265 return -ENOMEM; 266 267 pwm_map->output = output; 268 pwm_map->num_outputs = num_outputs; 269 pdata->pwms[i] = pwm_map; 270 271 count++; 272 } 273 274 if (count == 0) 275 return -ENODATA; 276 277 lp3943_pwm->pdata = pdata; 278 return 0; 279 } 280 281 static int lp3943_pwm_probe(struct platform_device *pdev) 282 { 283 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); 284 struct lp3943_pwm *lp3943_pwm; 285 int ret; 286 287 lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL); 288 if (!lp3943_pwm) 289 return -ENOMEM; 290 291 lp3943_pwm->pdata = lp3943->pdata; 292 if (!lp3943_pwm->pdata) { 293 if (IS_ENABLED(CONFIG_OF)) 294 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); 295 else 296 ret = -ENODEV; 297 298 if (ret) 299 return ret; 300 } 301 302 lp3943_pwm->lp3943 = lp3943; 303 lp3943_pwm->chip.dev = &pdev->dev; 304 lp3943_pwm->chip.ops = &lp3943_pwm_ops; 305 lp3943_pwm->chip.npwm = LP3943_NUM_PWMS; 306 307 return devm_pwmchip_add(&pdev->dev, &lp3943_pwm->chip); 308 } 309 310 #ifdef CONFIG_OF 311 static const struct of_device_id lp3943_pwm_of_match[] = { 312 { .compatible = "ti,lp3943-pwm", }, 313 { } 314 }; 315 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); 316 #endif 317 318 static struct platform_driver lp3943_pwm_driver = { 319 .probe = lp3943_pwm_probe, 320 .driver = { 321 .name = "lp3943-pwm", 322 .of_match_table = of_match_ptr(lp3943_pwm_of_match), 323 }, 324 }; 325 module_platform_driver(lp3943_pwm_driver); 326 327 MODULE_DESCRIPTION("LP3943 PWM driver"); 328 MODULE_ALIAS("platform:lp3943-pwm"); 329 MODULE_AUTHOR("Milo Kim"); 330 MODULE_LICENSE("GPL"); 331