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/i2c.h> 12 #include <linux/mfd/lp3943.h> 13 #include <linux/module.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 int duty_ns, int 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 period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD); 122 val = (u8)(period_ns / LP3943_MIN_PERIOD - 1); 123 124 err = lp3943_write_byte(lp3943, reg_prescale, val); 125 if (err) 126 return err; 127 128 val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns); 129 130 return lp3943_write_byte(lp3943, reg_duty, val); 131 } 132 133 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, 134 struct lp3943_pwm_map *pwm_map, 135 u8 val) 136 { 137 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 138 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; 139 int i, index, err; 140 141 for (i = 0; i < pwm_map->num_outputs; i++) { 142 index = pwm_map->output[i]; 143 err = lp3943_update_bits(lp3943, mux[index].reg, 144 mux[index].mask, 145 val << mux[index].shift); 146 if (err) 147 return err; 148 } 149 150 return 0; 151 } 152 153 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 154 { 155 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 156 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 157 u8 val; 158 159 if (pwm->hwpwm == 0) 160 val = LP3943_DIM_PWM0; 161 else 162 val = LP3943_DIM_PWM1; 163 164 /* 165 * Each PWM generator is set to control any of outputs of LP3943. 166 * To enable/disable the PWM, these output pins should be configured. 167 */ 168 169 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); 170 } 171 172 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 173 { 174 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 175 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 176 177 /* 178 * LP3943 outputs are open-drain, so the pin should be configured 179 * when the PWM is disabled. 180 */ 181 182 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); 183 } 184 185 static const struct pwm_ops lp3943_pwm_ops = { 186 .request = lp3943_pwm_request, 187 .free = lp3943_pwm_free, 188 .config = lp3943_pwm_config, 189 .enable = lp3943_pwm_enable, 190 .disable = lp3943_pwm_disable, 191 .owner = THIS_MODULE, 192 }; 193 194 static int lp3943_pwm_parse_dt(struct device *dev, 195 struct lp3943_pwm *lp3943_pwm) 196 { 197 static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; 198 struct device_node *node = dev->of_node; 199 struct lp3943_platform_data *pdata; 200 struct lp3943_pwm_map *pwm_map; 201 enum lp3943_pwm_output *output; 202 int i, err, proplen, count = 0; 203 u32 num_outputs; 204 205 if (!node) 206 return -EINVAL; 207 208 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 209 if (!pdata) 210 return -ENOMEM; 211 212 /* 213 * Read the output map configuration from the device tree. 214 * Each of the two PWM generators can drive zero or more outputs. 215 */ 216 217 for (i = 0; i < LP3943_NUM_PWMS; i++) { 218 if (!of_get_property(node, name[i], &proplen)) 219 continue; 220 221 num_outputs = proplen / sizeof(u32); 222 if (num_outputs == 0) 223 continue; 224 225 output = devm_kcalloc(dev, num_outputs, sizeof(*output), 226 GFP_KERNEL); 227 if (!output) 228 return -ENOMEM; 229 230 err = of_property_read_u32_array(node, name[i], output, 231 num_outputs); 232 if (err) 233 return err; 234 235 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); 236 if (!pwm_map) 237 return -ENOMEM; 238 239 pwm_map->output = output; 240 pwm_map->num_outputs = num_outputs; 241 pdata->pwms[i] = pwm_map; 242 243 count++; 244 } 245 246 if (count == 0) 247 return -ENODATA; 248 249 lp3943_pwm->pdata = pdata; 250 return 0; 251 } 252 253 static int lp3943_pwm_probe(struct platform_device *pdev) 254 { 255 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); 256 struct lp3943_pwm *lp3943_pwm; 257 int ret; 258 259 lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL); 260 if (!lp3943_pwm) 261 return -ENOMEM; 262 263 lp3943_pwm->pdata = lp3943->pdata; 264 if (!lp3943_pwm->pdata) { 265 if (IS_ENABLED(CONFIG_OF)) 266 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); 267 else 268 ret = -ENODEV; 269 270 if (ret) 271 return ret; 272 } 273 274 lp3943_pwm->lp3943 = lp3943; 275 lp3943_pwm->chip.dev = &pdev->dev; 276 lp3943_pwm->chip.ops = &lp3943_pwm_ops; 277 lp3943_pwm->chip.npwm = LP3943_NUM_PWMS; 278 279 platform_set_drvdata(pdev, lp3943_pwm); 280 281 return pwmchip_add(&lp3943_pwm->chip); 282 } 283 284 static int lp3943_pwm_remove(struct platform_device *pdev) 285 { 286 struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev); 287 288 return pwmchip_remove(&lp3943_pwm->chip); 289 } 290 291 #ifdef CONFIG_OF 292 static const struct of_device_id lp3943_pwm_of_match[] = { 293 { .compatible = "ti,lp3943-pwm", }, 294 { } 295 }; 296 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); 297 #endif 298 299 static struct platform_driver lp3943_pwm_driver = { 300 .probe = lp3943_pwm_probe, 301 .remove = lp3943_pwm_remove, 302 .driver = { 303 .name = "lp3943-pwm", 304 .of_match_table = of_match_ptr(lp3943_pwm_of_match), 305 }, 306 }; 307 module_platform_driver(lp3943_pwm_driver); 308 309 MODULE_DESCRIPTION("LP3943 PWM driver"); 310 MODULE_ALIAS("platform:lp3943-pwm"); 311 MODULE_AUTHOR("Milo Kim"); 312 MODULE_LICENSE("GPL"); 313