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1// SPDX-License-Identifier: GPL-2.02// Copyright (c) 2018 Crane Merchandising Systems. All rights reserved.3// Copyright (C) 2018 Oleh Kravchenko <oleg@kaa.org.ua>4 5#include <linux/delay.h>6#include <linux/leds.h>7#include <linux/mod_devicetable.h>8#include <linux/module.h>9#include <linux/spi/spi.h>10#include <linux/workqueue.h>11 12/*13 * CR0014114 SPI protocol descrtiption:14 * +----+-----------------------------------+----+15 * | CMD| BRIGHTNESS |CRC |16 * +----+-----------------------------------+----+17 * | | LED0| LED1| LED2| LED3| LED4| LED5| |18 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |19 * | |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B| |20 * | 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1 |21 * | |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1| |22 * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |23 * | | 18 | |24 * +----+-----------------------------------+----+25 * | 20 |26 * +---------------------------------------------+27 *28 * PS: Boards can be connected to the chain:29 * SPI -> board0 -> board1 -> board2 ..30 */31 32/* CR0014114 SPI commands */33#define CR_SET_BRIGHTNESS 0x8034#define CR_INIT_REENUMERATE 0x8135#define CR_NEXT_REENUMERATE 0x8236 37/* CR0014114 default settings */38#define CR_MAX_BRIGHTNESS GENMASK(6, 0)39#define CR_FW_DELAY_MSEC 1040#define CR_RECOUNT_DELAY (HZ * 3600)41 42#define CR_DEV_NAME "cr0014114"43 44struct cr0014114_led {45 struct cr0014114 *priv;46 struct led_classdev ldev;47 u8 brightness;48};49 50struct cr0014114 {51 bool do_recount;52 size_t count;53 struct delayed_work work;54 struct device *dev;55 struct mutex lock;56 struct spi_device *spi;57 u8 *buf;58 unsigned long delay;59 struct cr0014114_led leds[] __counted_by(count);60};61 62static void cr0014114_calc_crc(u8 *buf, const size_t len)63{64 size_t i;65 u8 crc;66 67 for (i = 1, crc = 1; i < len - 1; i++)68 crc += buf[i];69 crc |= BIT(7);70 71 /* special case when CRC matches the SPI commands */72 if (crc == CR_SET_BRIGHTNESS ||73 crc == CR_INIT_REENUMERATE ||74 crc == CR_NEXT_REENUMERATE)75 crc = 0xfe;76 77 buf[len - 1] = crc;78}79 80static int cr0014114_recount(struct cr0014114 *priv)81{82 int ret;83 size_t i;84 u8 cmd;85 86 dev_dbg(priv->dev, "LEDs recount is started\n");87 88 cmd = CR_INIT_REENUMERATE;89 ret = spi_write(priv->spi, &cmd, sizeof(cmd));90 if (ret)91 goto err;92 93 cmd = CR_NEXT_REENUMERATE;94 for (i = 0; i < priv->count; i++) {95 msleep(CR_FW_DELAY_MSEC);96 97 ret = spi_write(priv->spi, &cmd, sizeof(cmd));98 if (ret)99 goto err;100 }101 102err:103 dev_dbg(priv->dev, "LEDs recount is finished\n");104 105 if (ret)106 dev_err(priv->dev, "with error %d", ret);107 108 return ret;109}110 111static int cr0014114_sync(struct cr0014114 *priv)112{113 int ret;114 size_t i;115 unsigned long udelay, now = jiffies;116 117 /* to avoid SPI mistiming with firmware we should wait some time */118 if (time_after(priv->delay, now)) {119 udelay = jiffies_to_usecs(priv->delay - now);120 usleep_range(udelay, udelay + 1);121 }122 123 if (unlikely(priv->do_recount)) {124 ret = cr0014114_recount(priv);125 if (ret)126 goto err;127 128 priv->do_recount = false;129 msleep(CR_FW_DELAY_MSEC);130 }131 132 priv->buf[0] = CR_SET_BRIGHTNESS;133 for (i = 0; i < priv->count; i++)134 priv->buf[i + 1] = priv->leds[i].brightness;135 cr0014114_calc_crc(priv->buf, priv->count + 2);136 ret = spi_write(priv->spi, priv->buf, priv->count + 2);137 138err:139 priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC);140 141 return ret;142}143 144static void cr0014114_recount_work(struct work_struct *work)145{146 int ret;147 struct cr0014114 *priv = container_of(work,148 struct cr0014114,149 work.work);150 151 mutex_lock(&priv->lock);152 priv->do_recount = true;153 ret = cr0014114_sync(priv);154 mutex_unlock(&priv->lock);155 156 if (ret)157 dev_warn(priv->dev, "sync of LEDs failed %d\n", ret);158 159 schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);160}161 162static int cr0014114_set_sync(struct led_classdev *ldev,163 enum led_brightness brightness)164{165 int ret;166 struct cr0014114_led *led = container_of(ldev,167 struct cr0014114_led,168 ldev);169 170 dev_dbg(led->priv->dev, "Set brightness to %d\n", brightness);171 172 mutex_lock(&led->priv->lock);173 led->brightness = (u8)brightness;174 ret = cr0014114_sync(led->priv);175 mutex_unlock(&led->priv->lock);176 177 return ret;178}179 180static int cr0014114_probe_dt(struct cr0014114 *priv)181{182 size_t i = 0;183 struct cr0014114_led *led;184 struct fwnode_handle *child;185 struct led_init_data init_data = {};186 int ret;187 188 device_for_each_child_node(priv->dev, child) {189 led = &priv->leds[i];190 191 led->priv = priv;192 led->ldev.max_brightness = CR_MAX_BRIGHTNESS;193 led->ldev.brightness_set_blocking = cr0014114_set_sync;194 195 init_data.fwnode = child;196 init_data.devicename = CR_DEV_NAME;197 init_data.default_label = ":";198 199 ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,200 &init_data);201 if (ret) {202 dev_err(priv->dev,203 "failed to register LED device, err %d", ret);204 fwnode_handle_put(child);205 return ret;206 }207 208 i++;209 }210 211 return 0;212}213 214static int cr0014114_probe(struct spi_device *spi)215{216 struct cr0014114 *priv;217 size_t count;218 int ret;219 220 count = device_get_child_node_count(&spi->dev);221 if (!count) {222 dev_err(&spi->dev, "LEDs are not defined in device tree!");223 return -ENODEV;224 }225 226 priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),227 GFP_KERNEL);228 if (!priv)229 return -ENOMEM;230 231 priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL);232 if (!priv->buf)233 return -ENOMEM;234 235 mutex_init(&priv->lock);236 INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work);237 priv->count = count;238 priv->dev = &spi->dev;239 priv->spi = spi;240 priv->delay = jiffies -241 msecs_to_jiffies(CR_FW_DELAY_MSEC);242 243 priv->do_recount = true;244 ret = cr0014114_sync(priv);245 if (ret) {246 dev_err(priv->dev, "first recount failed %d\n", ret);247 return ret;248 }249 250 priv->do_recount = true;251 ret = cr0014114_sync(priv);252 if (ret) {253 dev_err(priv->dev, "second recount failed %d\n", ret);254 return ret;255 }256 257 ret = cr0014114_probe_dt(priv);258 if (ret)259 return ret;260 261 /* setup recount work to workaround buggy firmware */262 schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY);263 264 spi_set_drvdata(spi, priv);265 266 return 0;267}268 269static void cr0014114_remove(struct spi_device *spi)270{271 struct cr0014114 *priv = spi_get_drvdata(spi);272 273 cancel_delayed_work_sync(&priv->work);274 mutex_destroy(&priv->lock);275}276 277static const struct of_device_id cr0014114_dt_ids[] = {278 { .compatible = "crane,cr0014114", },279 {},280};281 282MODULE_DEVICE_TABLE(of, cr0014114_dt_ids);283 284static struct spi_driver cr0014114_driver = {285 .probe = cr0014114_probe,286 .remove = cr0014114_remove,287 .driver = {288 .name = KBUILD_MODNAME,289 .of_match_table = cr0014114_dt_ids,290 },291};292 293module_spi_driver(cr0014114_driver);294 295MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");296MODULE_DESCRIPTION("cr0014114 LED driver");297MODULE_LICENSE("GPL v2");298MODULE_ALIAS("spi:cr0014114");299