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