// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Crane Merchandising Systems. All rights reserved. // Copyright (C) 2018 Oleh Kravchenko <oleg@kaa.org.ua> #include <linux/delay.h> #include <linux/leds.h> #include <linux/module.h> #include <linux/of_device.h> #include <linux/spi/spi.h> #include <linux/workqueue.h> #include <uapi/linux/uleds.h> /* * CR0014114 SPI protocol descrtiption: * +----+-----------------------------------+----+ * | CMD| BRIGHTNESS |CRC | * +----+-----------------------------------+----+ * | | LED0| LED1| LED2| LED3| LED4| LED5| | * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | * | |R|G|B|R|G|B|R|G|B|R|G|B|R|G|B|R|G|B| | * | 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 1 | * | |1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1|1| | * | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | * | | 18 | | * +----+-----------------------------------+----+ * | 20 | * +---------------------------------------------+ * * PS: Boards can be connected to the chain: * SPI -> board0 -> board1 -> board2 .. */ /* CR0014114 SPI commands */ #define CR_SET_BRIGHTNESS 0x80 #define CR_INIT_REENUMERATE 0x81 #define CR_NEXT_REENUMERATE 0x82 /* CR0014114 default settings */ #define CR_MAX_BRIGHTNESS GENMASK(6, 0) #define CR_FW_DELAY_MSEC 10 #define CR_RECOUNT_DELAY (HZ * 3600) struct cr0014114_led { char name[LED_MAX_NAME_SIZE]; struct cr0014114 *priv; struct led_classdev ldev; u8 brightness; }; struct cr0014114 { bool do_recount; size_t count; struct delayed_work work; struct device *dev; struct mutex lock; struct spi_device *spi; u8 *buf; unsigned long delay; struct cr0014114_led leds[]; }; static void cr0014114_calc_crc(u8 *buf, const size_t len) { size_t i; u8 crc; for (i = 1, crc = 1; i < len - 1; i++) crc += buf[i]; crc |= BIT(7); /* special case when CRC matches the SPI commands */ if (crc == CR_SET_BRIGHTNESS || crc == CR_INIT_REENUMERATE || crc == CR_NEXT_REENUMERATE) crc = 0xfe; buf[len - 1] = crc; } static int cr0014114_recount(struct cr0014114 *priv) { int ret; size_t i; u8 cmd; dev_dbg(priv->dev, "LEDs recount is started\n"); cmd = CR_INIT_REENUMERATE; ret = spi_write(priv->spi, &cmd, sizeof(cmd)); if (ret) goto err; cmd = CR_NEXT_REENUMERATE; for (i = 0; i < priv->count; i++) { msleep(CR_FW_DELAY_MSEC); ret = spi_write(priv->spi, &cmd, sizeof(cmd)); if (ret) goto err; } err: dev_dbg(priv->dev, "LEDs recount is finished\n"); if (ret) dev_err(priv->dev, "with error %d", ret); return ret; } static int cr0014114_sync(struct cr0014114 *priv) { int ret; size_t i; unsigned long udelay, now = jiffies; /* to avoid SPI mistiming with firmware we should wait some time */ if (time_after(priv->delay, now)) { udelay = jiffies_to_usecs(priv->delay - now); usleep_range(udelay, udelay + 1); } if (unlikely(priv->do_recount)) { ret = cr0014114_recount(priv); if (ret) goto err; priv->do_recount = false; msleep(CR_FW_DELAY_MSEC); } priv->buf[0] = CR_SET_BRIGHTNESS; for (i = 0; i < priv->count; i++) priv->buf[i + 1] = priv->leds[i].brightness; cr0014114_calc_crc(priv->buf, priv->count + 2); ret = spi_write(priv->spi, priv->buf, priv->count + 2); err: priv->delay = jiffies + msecs_to_jiffies(CR_FW_DELAY_MSEC); return ret; } static void cr0014114_recount_work(struct work_struct *work) { int ret; struct cr0014114 *priv = container_of(work, struct cr0014114, work.work); mutex_lock(&priv->lock); priv->do_recount = true; ret = cr0014114_sync(priv); mutex_unlock(&priv->lock); if (ret) dev_warn(priv->dev, "sync of LEDs failed %d\n", ret); schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY); } static int cr0014114_set_sync(struct led_classdev *ldev, enum led_brightness brightness) { int ret; struct cr0014114_led *led = container_of(ldev, struct cr0014114_led, ldev); dev_dbg(led->priv->dev, "Set brightness of %s to %d\n", led->name, brightness); mutex_lock(&led->priv->lock); led->brightness = (u8)brightness; ret = cr0014114_sync(led->priv); mutex_unlock(&led->priv->lock); return ret; } static int cr0014114_probe_dt(struct cr0014114 *priv) { size_t i = 0; struct cr0014114_led *led; struct fwnode_handle *child; struct device_node *np; int ret; const char *str; device_for_each_child_node(priv->dev, child) { np = to_of_node(child); led = &priv->leds[i]; ret = fwnode_property_read_string(child, "label", &str); if (ret) snprintf(led->name, sizeof(led->name), "cr0014114::"); else snprintf(led->name, sizeof(led->name), "cr0014114:%s", str); fwnode_property_read_string(child, "linux,default-trigger", &led->ldev.default_trigger); led->priv = priv; led->ldev.name = led->name; led->ldev.max_brightness = CR_MAX_BRIGHTNESS; led->ldev.brightness_set_blocking = cr0014114_set_sync; ret = devm_of_led_classdev_register(priv->dev, np, &led->ldev); if (ret) { dev_err(priv->dev, "failed to register LED device %s, err %d", led->name, ret); fwnode_handle_put(child); return ret; } led->ldev.dev->of_node = np; i++; } return 0; } static int cr0014114_probe(struct spi_device *spi) { struct cr0014114 *priv; size_t count; int ret; count = device_get_child_node_count(&spi->dev); if (!count) { dev_err(&spi->dev, "LEDs are not defined in device tree!"); return -ENODEV; } priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count), GFP_KERNEL); if (!priv) return -ENOMEM; priv->buf = devm_kzalloc(&spi->dev, count + 2, GFP_KERNEL); if (!priv->buf) return -ENOMEM; mutex_init(&priv->lock); INIT_DELAYED_WORK(&priv->work, cr0014114_recount_work); priv->count = count; priv->dev = &spi->dev; priv->spi = spi; priv->delay = jiffies - msecs_to_jiffies(CR_FW_DELAY_MSEC); priv->do_recount = true; ret = cr0014114_sync(priv); if (ret) { dev_err(priv->dev, "first recount failed %d\n", ret); return ret; } priv->do_recount = true; ret = cr0014114_sync(priv); if (ret) { dev_err(priv->dev, "second recount failed %d\n", ret); return ret; } ret = cr0014114_probe_dt(priv); if (ret) return ret; /* setup recount work to workaround buggy firmware */ schedule_delayed_work(&priv->work, CR_RECOUNT_DELAY); spi_set_drvdata(spi, priv); return 0; } static int cr0014114_remove(struct spi_device *spi) { struct cr0014114 *priv = spi_get_drvdata(spi); cancel_delayed_work_sync(&priv->work); mutex_destroy(&priv->lock); return 0; } static const struct of_device_id cr0014114_dt_ids[] = { { .compatible = "crane,cr0014114", }, {}, }; MODULE_DEVICE_TABLE(of, cr0014114_dt_ids); static struct spi_driver cr0014114_driver = { .probe = cr0014114_probe, .remove = cr0014114_remove, .driver = { .name = KBUILD_MODNAME, .of_match_table = cr0014114_dt_ids, }, }; module_spi_driver(cr0014114_driver); MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>"); MODULE_DESCRIPTION("cr0014114 LED driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("spi:cr0014114");