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 lp3943 *lp3943; 24 struct lp3943_platform_data *pdata; 25 struct lp3943_pwm_map pwm_map[LP3943_NUM_PWMS]; 26 }; 27 28 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *chip) 29 { 30 return pwmchip_get_drvdata(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 = &lp3943_pwm->pwm_map[hwpwm]; 39 int i, offset; 40 41 pwm_map->output = pdata->pwms[hwpwm]->output; 42 pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs; 43 44 for (i = 0; i < pwm_map->num_outputs; i++) { 45 offset = pwm_map->output[i]; 46 47 /* Return an error if the pin is already assigned */ 48 if (test_and_set_bit(offset, &lp3943->pin_used)) 49 return ERR_PTR(-EBUSY); 50 } 51 52 return pwm_map; 53 } 54 55 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 56 { 57 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 58 struct lp3943_pwm_map *pwm_map; 59 60 pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm); 61 if (IS_ERR(pwm_map)) 62 return PTR_ERR(pwm_map); 63 64 return 0; 65 } 66 67 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm, 68 struct lp3943_pwm_map *pwm_map) 69 { 70 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 71 int i, offset; 72 73 for (i = 0; i < pwm_map->num_outputs; i++) { 74 offset = pwm_map->output[i]; 75 clear_bit(offset, &lp3943->pin_used); 76 } 77 } 78 79 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 80 { 81 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 82 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm]; 83 84 lp3943_pwm_free_map(lp3943_pwm, pwm_map); 85 } 86 87 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 88 u64 duty_ns, u64 period_ns) 89 { 90 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 91 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 92 u8 val, reg_duty, reg_prescale; 93 int err; 94 95 /* 96 * How to configure the LP3943 PWMs 97 * 98 * 1) Period = 6250 ~ 1600000 99 * 2) Prescale = period / 6250 -1 100 * 3) Duty = input duty 101 * 102 * Prescale and duty are register values 103 */ 104 105 if (pwm->hwpwm == 0) { 106 reg_prescale = LP3943_REG_PRESCALE0; 107 reg_duty = LP3943_REG_PWM0; 108 } else { 109 reg_prescale = LP3943_REG_PRESCALE1; 110 reg_duty = LP3943_REG_PWM1; 111 } 112 113 /* 114 * Note that after this clamping, period_ns fits into an int. This is 115 * helpful because we can resort to integer division below instead of 116 * the (more expensive) 64 bit division. 117 */ 118 period_ns = clamp(period_ns, (u64)LP3943_MIN_PERIOD, (u64)LP3943_MAX_PERIOD); 119 val = (u8)((int)period_ns / LP3943_MIN_PERIOD - 1); 120 121 err = lp3943_write_byte(lp3943, reg_prescale, val); 122 if (err) 123 return err; 124 125 duty_ns = min(duty_ns, period_ns); 126 val = (u8)((int)duty_ns * LP3943_MAX_DUTY / (int)period_ns); 127 128 return lp3943_write_byte(lp3943, reg_duty, val); 129 } 130 131 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, 132 struct lp3943_pwm_map *pwm_map, 133 u8 val) 134 { 135 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 136 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; 137 int i, index, err; 138 139 for (i = 0; i < pwm_map->num_outputs; i++) { 140 index = pwm_map->output[i]; 141 err = lp3943_update_bits(lp3943, mux[index].reg, 142 mux[index].mask, 143 val << mux[index].shift); 144 if (err) 145 return err; 146 } 147 148 return 0; 149 } 150 151 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 152 { 153 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 154 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm]; 155 u8 val; 156 157 if (pwm->hwpwm == 0) 158 val = LP3943_DIM_PWM0; 159 else 160 val = LP3943_DIM_PWM1; 161 162 /* 163 * Each PWM generator is set to control any of outputs of LP3943. 164 * To enable/disable the PWM, these output pins should be configured. 165 */ 166 167 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); 168 } 169 170 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 171 { 172 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 173 struct lp3943_pwm_map *pwm_map = &lp3943_pwm->pwm_map[pwm->hwpwm]; 174 175 /* 176 * LP3943 outputs are open-drain, so the pin should be configured 177 * when the PWM is disabled. 178 */ 179 180 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); 181 } 182 183 static int lp3943_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 184 const struct pwm_state *state) 185 { 186 int err; 187 188 if (state->polarity != PWM_POLARITY_NORMAL) 189 return -EINVAL; 190 191 if (!state->enabled) { 192 if (pwm->state.enabled) 193 lp3943_pwm_disable(chip, pwm); 194 return 0; 195 } 196 197 err = lp3943_pwm_config(chip, pwm, state->duty_cycle, state->period); 198 if (err) 199 return err; 200 201 if (!pwm->state.enabled) 202 err = lp3943_pwm_enable(chip, pwm); 203 204 return err; 205 } 206 207 static const struct pwm_ops lp3943_pwm_ops = { 208 .request = lp3943_pwm_request, 209 .free = lp3943_pwm_free, 210 .apply = lp3943_pwm_apply, 211 }; 212 213 static int lp3943_pwm_parse_dt(struct device *dev, 214 struct lp3943_pwm *lp3943_pwm) 215 { 216 static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; 217 struct device_node *node = dev->of_node; 218 struct lp3943_platform_data *pdata; 219 struct lp3943_pwm_map *pwm_map; 220 enum lp3943_pwm_output *output; 221 int i, err, num_outputs, count = 0; 222 223 if (!node) 224 return -EINVAL; 225 226 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 227 if (!pdata) 228 return -ENOMEM; 229 230 /* 231 * Read the output map configuration from the device tree. 232 * Each of the two PWM generators can drive zero or more outputs. 233 */ 234 235 for (i = 0; i < LP3943_NUM_PWMS; i++) { 236 num_outputs = of_property_count_u32_elems(node, name[i]); 237 if (num_outputs <= 0) 238 continue; 239 240 output = devm_kcalloc(dev, num_outputs, sizeof(*output), 241 GFP_KERNEL); 242 if (!output) 243 return -ENOMEM; 244 245 err = of_property_read_u32_array(node, name[i], output, 246 num_outputs); 247 if (err) 248 return err; 249 250 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); 251 if (!pwm_map) 252 return -ENOMEM; 253 254 pwm_map->output = output; 255 pwm_map->num_outputs = num_outputs; 256 pdata->pwms[i] = pwm_map; 257 258 count++; 259 } 260 261 if (count == 0) 262 return -ENODATA; 263 264 lp3943_pwm->pdata = pdata; 265 return 0; 266 } 267 268 static int lp3943_pwm_probe(struct platform_device *pdev) 269 { 270 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); 271 struct pwm_chip *chip; 272 struct lp3943_pwm *lp3943_pwm; 273 int ret; 274 275 chip = devm_pwmchip_alloc(&pdev->dev, LP3943_NUM_PWMS, sizeof(*lp3943_pwm)); 276 if (IS_ERR(chip)) 277 return PTR_ERR(chip); 278 lp3943_pwm = to_lp3943_pwm(chip); 279 280 lp3943_pwm->pdata = lp3943->pdata; 281 if (!lp3943_pwm->pdata) { 282 if (IS_ENABLED(CONFIG_OF)) 283 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); 284 else 285 ret = -ENODEV; 286 287 if (ret) 288 return ret; 289 } 290 291 lp3943_pwm->lp3943 = lp3943; 292 chip->ops = &lp3943_pwm_ops; 293 294 return devm_pwmchip_add(&pdev->dev, chip); 295 } 296 297 #ifdef CONFIG_OF 298 static const struct of_device_id lp3943_pwm_of_match[] = { 299 { .compatible = "ti,lp3943-pwm", }, 300 { } 301 }; 302 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); 303 #endif 304 305 static struct platform_driver lp3943_pwm_driver = { 306 .probe = lp3943_pwm_probe, 307 .driver = { 308 .name = "lp3943-pwm", 309 .of_match_table = of_match_ptr(lp3943_pwm_of_match), 310 }, 311 }; 312 module_platform_driver(lp3943_pwm_driver); 313 314 MODULE_DESCRIPTION("LP3943 PWM driver"); 315 MODULE_ALIAS("platform:lp3943-pwm"); 316 MODULE_AUTHOR("Milo Kim"); 317 MODULE_LICENSE("GPL"); 318