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