--- /dev/null
+// 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,
+ sizeof(*priv) + sizeof(*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");
projects / platform / kernel / linux-rpi.git / commitdiff