1 /* 2 * TI/National Semiconductor LP3943 PWM driver 3 * 4 * Copyright 2013 Texas Instruments 5 * 6 * Author: Milo Kim <milo.kim@ti.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; version 2. 11 */ 12 13 #include <linux/err.h> 14 #include <linux/i2c.h> 15 #include <linux/mfd/lp3943.h> 16 #include <linux/module.h> 17 #include <linux/platform_device.h> 18 #include <linux/pwm.h> 19 #include <linux/slab.h> 20 21 #define LP3943_MAX_DUTY 255 22 #define LP3943_MIN_PERIOD 6250 23 #define LP3943_MAX_PERIOD 1600000 24 25 struct lp3943_pwm { 26 struct pwm_chip chip; 27 struct lp3943 *lp3943; 28 struct lp3943_platform_data *pdata; 29 }; 30 31 static inline struct lp3943_pwm *to_lp3943_pwm(struct pwm_chip *_chip) 32 { 33 return container_of(_chip, struct lp3943_pwm, chip); 34 } 35 36 static struct lp3943_pwm_map * 37 lp3943_pwm_request_map(struct lp3943_pwm *lp3943_pwm, int hwpwm) 38 { 39 struct lp3943_platform_data *pdata = lp3943_pwm->pdata; 40 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 41 struct lp3943_pwm_map *pwm_map; 42 int i, offset; 43 44 pwm_map = kzalloc(sizeof(*pwm_map), GFP_KERNEL); 45 if (!pwm_map) 46 return ERR_PTR(-ENOMEM); 47 48 pwm_map->output = pdata->pwms[hwpwm]->output; 49 pwm_map->num_outputs = pdata->pwms[hwpwm]->num_outputs; 50 51 for (i = 0; i < pwm_map->num_outputs; i++) { 52 offset = pwm_map->output[i]; 53 54 /* Return an error if the pin is already assigned */ 55 if (test_and_set_bit(offset, &lp3943->pin_used)) { 56 kfree(pwm_map); 57 return ERR_PTR(-EBUSY); 58 } 59 } 60 61 return pwm_map; 62 } 63 64 static int lp3943_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 65 { 66 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 67 struct lp3943_pwm_map *pwm_map; 68 69 pwm_map = lp3943_pwm_request_map(lp3943_pwm, pwm->hwpwm); 70 if (IS_ERR(pwm_map)) 71 return PTR_ERR(pwm_map); 72 73 return pwm_set_chip_data(pwm, pwm_map); 74 } 75 76 static void lp3943_pwm_free_map(struct lp3943_pwm *lp3943_pwm, 77 struct lp3943_pwm_map *pwm_map) 78 { 79 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 80 int i, offset; 81 82 for (i = 0; i < pwm_map->num_outputs; i++) { 83 offset = pwm_map->output[i]; 84 clear_bit(offset, &lp3943->pin_used); 85 } 86 87 kfree(pwm_map); 88 } 89 90 static void lp3943_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 91 { 92 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 93 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 94 95 lp3943_pwm_free_map(lp3943_pwm, pwm_map); 96 } 97 98 static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 99 int duty_ns, int period_ns) 100 { 101 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 102 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 103 u8 val, reg_duty, reg_prescale; 104 int err; 105 106 /* 107 * How to configure the LP3943 PWMs 108 * 109 * 1) Period = 6250 ~ 1600000 110 * 2) Prescale = period / 6250 -1 111 * 3) Duty = input duty 112 * 113 * Prescale and duty are register values 114 */ 115 116 if (pwm->hwpwm == 0) { 117 reg_prescale = LP3943_REG_PRESCALE0; 118 reg_duty = LP3943_REG_PWM0; 119 } else { 120 reg_prescale = LP3943_REG_PRESCALE1; 121 reg_duty = LP3943_REG_PWM1; 122 } 123 124 period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD); 125 val = (u8)(period_ns / LP3943_MIN_PERIOD - 1); 126 127 err = lp3943_write_byte(lp3943, reg_prescale, val); 128 if (err) 129 return err; 130 131 val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns); 132 133 return lp3943_write_byte(lp3943, reg_duty, val); 134 } 135 136 static int lp3943_pwm_set_mode(struct lp3943_pwm *lp3943_pwm, 137 struct lp3943_pwm_map *pwm_map, 138 u8 val) 139 { 140 struct lp3943 *lp3943 = lp3943_pwm->lp3943; 141 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; 142 int i, index, err; 143 144 for (i = 0; i < pwm_map->num_outputs; i++) { 145 index = pwm_map->output[i]; 146 err = lp3943_update_bits(lp3943, mux[index].reg, 147 mux[index].mask, 148 val << mux[index].shift); 149 if (err) 150 return err; 151 } 152 153 return 0; 154 } 155 156 static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 157 { 158 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 159 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 160 u8 val; 161 162 if (pwm->hwpwm == 0) 163 val = LP3943_DIM_PWM0; 164 else 165 val = LP3943_DIM_PWM1; 166 167 /* 168 * Each PWM generator is set to control any of outputs of LP3943. 169 * To enable/disable the PWM, these output pins should be configured. 170 */ 171 172 return lp3943_pwm_set_mode(lp3943_pwm, pwm_map, val); 173 } 174 175 static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 176 { 177 struct lp3943_pwm *lp3943_pwm = to_lp3943_pwm(chip); 178 struct lp3943_pwm_map *pwm_map = pwm_get_chip_data(pwm); 179 180 /* 181 * LP3943 outputs are open-drain, so the pin should be configured 182 * when the PWM is disabled. 183 */ 184 185 lp3943_pwm_set_mode(lp3943_pwm, pwm_map, LP3943_GPIO_OUT_HIGH); 186 } 187 188 static const struct pwm_ops lp3943_pwm_ops = { 189 .request = lp3943_pwm_request, 190 .free = lp3943_pwm_free, 191 .config = lp3943_pwm_config, 192 .enable = lp3943_pwm_enable, 193 .disable = lp3943_pwm_disable, 194 .owner = THIS_MODULE, 195 }; 196 197 static int lp3943_pwm_parse_dt(struct device *dev, 198 struct lp3943_pwm *lp3943_pwm) 199 { 200 static const char * const name[] = { "ti,pwm0", "ti,pwm1", }; 201 struct device_node *node = dev->of_node; 202 struct lp3943_platform_data *pdata; 203 struct lp3943_pwm_map *pwm_map; 204 enum lp3943_pwm_output *output; 205 int i, err, proplen, count = 0; 206 u32 num_outputs; 207 208 if (!node) 209 return -EINVAL; 210 211 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 212 if (!pdata) 213 return -ENOMEM; 214 215 /* 216 * Read the output map configuration from the device tree. 217 * Each of the two PWM generators can drive zero or more outputs. 218 */ 219 220 for (i = 0; i < LP3943_NUM_PWMS; i++) { 221 if (!of_get_property(node, name[i], &proplen)) 222 continue; 223 224 num_outputs = proplen / sizeof(u32); 225 if (num_outputs == 0) 226 continue; 227 228 output = devm_kzalloc(dev, sizeof(*output) * num_outputs, 229 GFP_KERNEL); 230 if (!output) 231 return -ENOMEM; 232 233 err = of_property_read_u32_array(node, name[i], output, 234 num_outputs); 235 if (err) 236 return err; 237 238 pwm_map = devm_kzalloc(dev, sizeof(*pwm_map), GFP_KERNEL); 239 if (!pwm_map) 240 return -ENOMEM; 241 242 pwm_map->output = output; 243 pwm_map->num_outputs = num_outputs; 244 pdata->pwms[i] = pwm_map; 245 246 count++; 247 } 248 249 if (count == 0) 250 return -ENODATA; 251 252 lp3943_pwm->pdata = pdata; 253 return 0; 254 } 255 256 static int lp3943_pwm_probe(struct platform_device *pdev) 257 { 258 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); 259 struct lp3943_pwm *lp3943_pwm; 260 int ret; 261 262 lp3943_pwm = devm_kzalloc(&pdev->dev, sizeof(*lp3943_pwm), GFP_KERNEL); 263 if (!lp3943_pwm) 264 return -ENOMEM; 265 266 lp3943_pwm->pdata = lp3943->pdata; 267 if (!lp3943_pwm->pdata) { 268 if (IS_ENABLED(CONFIG_OF)) 269 ret = lp3943_pwm_parse_dt(&pdev->dev, lp3943_pwm); 270 else 271 ret = -ENODEV; 272 273 if (ret) 274 return ret; 275 } 276 277 lp3943_pwm->lp3943 = lp3943; 278 lp3943_pwm->chip.dev = &pdev->dev; 279 lp3943_pwm->chip.ops = &lp3943_pwm_ops; 280 lp3943_pwm->chip.npwm = LP3943_NUM_PWMS; 281 282 platform_set_drvdata(pdev, lp3943_pwm); 283 284 return pwmchip_add(&lp3943_pwm->chip); 285 } 286 287 static int lp3943_pwm_remove(struct platform_device *pdev) 288 { 289 struct lp3943_pwm *lp3943_pwm = platform_get_drvdata(pdev); 290 291 return pwmchip_remove(&lp3943_pwm->chip); 292 } 293 294 #ifdef CONFIG_OF 295 static const struct of_device_id lp3943_pwm_of_match[] = { 296 { .compatible = "ti,lp3943-pwm", }, 297 { } 298 }; 299 MODULE_DEVICE_TABLE(of, lp3943_pwm_of_match); 300 #endif 301 302 static struct platform_driver lp3943_pwm_driver = { 303 .probe = lp3943_pwm_probe, 304 .remove = lp3943_pwm_remove, 305 .driver = { 306 .name = "lp3943-pwm", 307 .of_match_table = of_match_ptr(lp3943_pwm_of_match), 308 }, 309 }; 310 module_platform_driver(lp3943_pwm_driver); 311 312 MODULE_DESCRIPTION("LP3943 PWM driver"); 313 MODULE_ALIAS("platform:lp3943-pwm"); 314 MODULE_AUTHOR("Milo Kim"); 315 MODULE_LICENSE("GPL"); 316