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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip4 *5 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>6 */7 8/*9 * I2C driver for National Semiconductor LP3944 Funlight Chip10 * http://www.national.com/pf/LP/LP3944.html11 *12 * This helper chip can drive up to 8 leds, with two programmable DIM modes;13 * it could even be used as a gpio expander but this driver assumes it is used14 * as a led controller.15 *16 * The DIM modes are used to set _blink_ patterns for leds, the pattern is17 * specified supplying two parameters:18 * - period: from 0s to 1.6s19 * - duty cycle: percentage of the period the led is on, from 0 to 10020 *21 * LP3944 can be found on Motorola A910 smartphone, where it drives the rgb22 * leds, the camera flash light and the displays backlights.23 */24 25#include <linux/module.h>26#include <linux/i2c.h>27#include <linux/slab.h>28#include <linux/leds.h>29#include <linux/mutex.h>30#include <linux/leds-lp3944.h>31 32/* Read Only Registers */33#define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */34#define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */35 36#define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */37#define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */38#define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */39#define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */40#define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */41#define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */42 43/* These registers are not used to control leds in LP3944, they can store44 * arbitrary values which the chip will ignore.45 */46#define LP3944_REG_REGISTER8 0x0847#define LP3944_REG_REGISTER9 0x0948 49#define LP3944_DIM0 050#define LP3944_DIM1 151 52/* period in ms */53#define LP3944_PERIOD_MIN 054#define LP3944_PERIOD_MAX 160055 56/* duty cycle is a percentage */57#define LP3944_DUTY_CYCLE_MIN 058#define LP3944_DUTY_CYCLE_MAX 10059 60#define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev)61 62/* Saved data */63struct lp3944_led_data {64 u8 id;65 enum lp3944_type type;66 struct led_classdev ldev;67 struct i2c_client *client;68};69 70struct lp3944_data {71 struct mutex lock;72 struct i2c_client *client;73 struct lp3944_led_data leds[LP3944_LEDS_MAX];74};75 76static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value)77{78 int tmp;79 80 tmp = i2c_smbus_read_byte_data(client, reg);81 if (tmp < 0)82 return tmp;83 84 *value = tmp;85 86 return 0;87}88 89static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value)90{91 return i2c_smbus_write_byte_data(client, reg, value);92}93 94/**95 * lp3944_dim_set_period() - Set the period for DIM status96 *97 * @client: the i2c client98 * @dim: either LP3944_DIM0 or LP3944_DIM199 * @period: period of a blink, that is a on/off cycle, expressed in ms.100 */101static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period)102{103 u8 psc_reg;104 u8 psc_value;105 int err;106 107 if (dim == LP3944_DIM0)108 psc_reg = LP3944_REG_PSC0;109 else if (dim == LP3944_DIM1)110 psc_reg = LP3944_REG_PSC1;111 else112 return -EINVAL;113 114 /* Convert period to Prescaler value */115 if (period > LP3944_PERIOD_MAX)116 return -EINVAL;117 118 psc_value = (period * 255) / LP3944_PERIOD_MAX;119 120 err = lp3944_reg_write(client, psc_reg, psc_value);121 122 return err;123}124 125/**126 * lp3944_dim_set_dutycycle - Set the duty cycle for DIM status127 *128 * @client: the i2c client129 * @dim: either LP3944_DIM0 or LP3944_DIM1130 * @duty_cycle: percentage of a period during which a led is ON131 */132static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim,133 u8 duty_cycle)134{135 u8 pwm_reg;136 u8 pwm_value;137 int err;138 139 if (dim == LP3944_DIM0)140 pwm_reg = LP3944_REG_PWM0;141 else if (dim == LP3944_DIM1)142 pwm_reg = LP3944_REG_PWM1;143 else144 return -EINVAL;145 146 /* Convert duty cycle to PWM value */147 if (duty_cycle > LP3944_DUTY_CYCLE_MAX)148 return -EINVAL;149 150 pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX;151 152 err = lp3944_reg_write(client, pwm_reg, pwm_value);153 154 return err;155}156 157/**158 * lp3944_led_set() - Set the led status159 *160 * @led: a lp3944_led_data structure161 * @status: one of LP3944_LED_STATUS_OFF162 * LP3944_LED_STATUS_ON163 * LP3944_LED_STATUS_DIM0164 * LP3944_LED_STATUS_DIM1165 */166static int lp3944_led_set(struct lp3944_led_data *led, u8 status)167{168 struct lp3944_data *data = i2c_get_clientdata(led->client);169 u8 id = led->id;170 u8 reg;171 u8 val = 0;172 int err;173 174 dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n",175 __func__, led->ldev.name, status);176 177 switch (id) {178 case LP3944_LED0:179 case LP3944_LED1:180 case LP3944_LED2:181 case LP3944_LED3:182 reg = LP3944_REG_LS0;183 break;184 case LP3944_LED4:185 case LP3944_LED5:186 case LP3944_LED6:187 case LP3944_LED7:188 id -= LP3944_LED4;189 reg = LP3944_REG_LS1;190 break;191 default:192 return -EINVAL;193 }194 195 if (status > LP3944_LED_STATUS_DIM1)196 return -EINVAL;197 198 /*199 * Invert status only when it's < 2 (i.e. 0 or 1) which means it's200 * controlling the on/off state directly.201 * When, instead, status is >= 2 don't invert it because it would mean202 * to mess with the hardware blinking mode.203 */204 if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2)205 status = 1 - status;206 207 mutex_lock(&data->lock);208 lp3944_reg_read(led->client, reg, &val);209 210 val &= ~(LP3944_LED_STATUS_MASK << (id << 1));211 val |= (status << (id << 1));212 213 dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n",214 __func__, led->ldev.name, reg, id, status, val);215 216 /* set led status */217 err = lp3944_reg_write(led->client, reg, val);218 mutex_unlock(&data->lock);219 220 return err;221}222 223static int lp3944_led_set_blink(struct led_classdev *led_cdev,224 unsigned long *delay_on,225 unsigned long *delay_off)226{227 struct lp3944_led_data *led = ldev_to_led(led_cdev);228 u16 period;229 u8 duty_cycle;230 int err;231 232 /* units are in ms */233 if (*delay_on + *delay_off > LP3944_PERIOD_MAX)234 return -EINVAL;235 236 if (*delay_on == 0 && *delay_off == 0) {237 /* Special case: the leds subsystem requires a default user238 * friendly blink pattern for the LED. Let's blink the led239 * slowly (1Hz).240 */241 *delay_on = 500;242 *delay_off = 500;243 }244 245 period = (*delay_on) + (*delay_off);246 247 /* duty_cycle is the percentage of period during which the led is ON */248 duty_cycle = 100 * (*delay_on) / period;249 250 /* invert duty cycle for inverted leds, this has the same effect of251 * swapping delay_on and delay_off252 */253 if (led->type == LP3944_LED_TYPE_LED_INVERTED)254 duty_cycle = 100 - duty_cycle;255 256 /* NOTE: using always the first DIM mode, this means that all leds257 * will have the same blinking pattern.258 *259 * We could find a way later to have two leds blinking in hardware260 * with different patterns at the same time, falling back to software261 * control for the other ones.262 */263 err = lp3944_dim_set_period(led->client, LP3944_DIM0, period);264 if (err)265 return err;266 267 err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle);268 if (err)269 return err;270 271 dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n",272 __func__);273 274 lp3944_led_set(led, LP3944_LED_STATUS_DIM0);275 276 return 0;277}278 279static int lp3944_led_set_brightness(struct led_classdev *led_cdev,280 enum led_brightness brightness)281{282 struct lp3944_led_data *led = ldev_to_led(led_cdev);283 284 dev_dbg(&led->client->dev, "%s: %s, %d\n",285 __func__, led_cdev->name, brightness);286 287 return lp3944_led_set(led, !!brightness);288}289 290static int lp3944_configure(struct i2c_client *client,291 struct lp3944_data *data,292 struct lp3944_platform_data *pdata)293{294 int i, err = 0;295 296 for (i = 0; i < pdata->leds_size; i++) {297 struct lp3944_led *pled = &pdata->leds[i];298 struct lp3944_led_data *led = &data->leds[i];299 led->client = client;300 led->id = i;301 302 switch (pled->type) {303 304 case LP3944_LED_TYPE_LED:305 case LP3944_LED_TYPE_LED_INVERTED:306 led->type = pled->type;307 led->ldev.name = pled->name;308 led->ldev.max_brightness = 1;309 led->ldev.brightness_set_blocking =310 lp3944_led_set_brightness;311 led->ldev.blink_set = lp3944_led_set_blink;312 led->ldev.flags = LED_CORE_SUSPENDRESUME;313 314 err = led_classdev_register(&client->dev, &led->ldev);315 if (err < 0) {316 dev_err(&client->dev,317 "couldn't register LED %s\n",318 led->ldev.name);319 goto exit;320 }321 322 /* to expose the default value to userspace */323 led->ldev.brightness =324 (enum led_brightness) pled->status;325 326 /* Set the default led status */327 err = lp3944_led_set(led, pled->status);328 if (err < 0) {329 dev_err(&client->dev,330 "%s couldn't set STATUS %d\n",331 led->ldev.name, pled->status);332 goto exit;333 }334 break;335 336 case LP3944_LED_TYPE_NONE:337 default:338 break;339 340 }341 }342 return 0;343 344exit:345 if (i > 0)346 for (i = i - 1; i >= 0; i--)347 switch (pdata->leds[i].type) {348 349 case LP3944_LED_TYPE_LED:350 case LP3944_LED_TYPE_LED_INVERTED:351 led_classdev_unregister(&data->leds[i].ldev);352 break;353 354 case LP3944_LED_TYPE_NONE:355 default:356 break;357 }358 359 return err;360}361 362static int lp3944_probe(struct i2c_client *client)363{364 struct lp3944_platform_data *lp3944_pdata =365 dev_get_platdata(&client->dev);366 struct lp3944_data *data;367 int err;368 369 if (lp3944_pdata == NULL) {370 dev_err(&client->dev, "no platform data\n");371 return -EINVAL;372 }373 374 /* Let's see whether this adapter can support what we need. */375 if (!i2c_check_functionality(client->adapter,376 I2C_FUNC_SMBUS_BYTE_DATA)) {377 dev_err(&client->dev, "insufficient functionality!\n");378 return -ENODEV;379 }380 381 data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data),382 GFP_KERNEL);383 if (!data)384 return -ENOMEM;385 386 data->client = client;387 i2c_set_clientdata(client, data);388 389 mutex_init(&data->lock);390 391 err = lp3944_configure(client, data, lp3944_pdata);392 if (err < 0)393 return err;394 395 dev_info(&client->dev, "lp3944 enabled\n");396 return 0;397}398 399static void lp3944_remove(struct i2c_client *client)400{401 struct lp3944_platform_data *pdata = dev_get_platdata(&client->dev);402 struct lp3944_data *data = i2c_get_clientdata(client);403 int i;404 405 for (i = 0; i < pdata->leds_size; i++)406 switch (data->leds[i].type) {407 case LP3944_LED_TYPE_LED:408 case LP3944_LED_TYPE_LED_INVERTED:409 led_classdev_unregister(&data->leds[i].ldev);410 break;411 412 case LP3944_LED_TYPE_NONE:413 default:414 break;415 }416}417 418/* lp3944 i2c driver struct */419static const struct i2c_device_id lp3944_id[] = {420 { "lp3944" },421 {}422};423 424MODULE_DEVICE_TABLE(i2c, lp3944_id);425 426static struct i2c_driver lp3944_driver = {427 .driver = {428 .name = "lp3944",429 },430 .probe = lp3944_probe,431 .remove = lp3944_remove,432 .id_table = lp3944_id,433};434 435module_i2c_driver(lp3944_driver);436 437MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");438MODULE_DESCRIPTION("LP3944 Fun Light Chip");439MODULE_LICENSE("GPL");440