// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Crane Merchandising Systems. All rights reserved.
// Copyright (C) 2018 Oleh Kravchenko <[email protected]>
#include <linux/delay.h>
#include <linux/leds.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
#include <linux/workqueue.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)
#define CR_DEV_NAME "cr0014114"
struct cr0014114_led {
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[] __counted_by(count);
};
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 to %d\n", 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 led_init_data init_data = {};
int ret;
device_for_each_child_node(priv->dev, child) {
led = &priv->leds[i];
led->priv = priv;
led->ldev.max_brightness = CR_MAX_BRIGHTNESS;
led->ldev.brightness_set_blocking = cr0014114_set_sync;
init_data.fwnode = child;
init_data.devicename = CR_DEV_NAME;
init_data.default_label = ":";
ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
&init_data);
if (ret) {
dev_err(priv->dev,
"failed to register LED device, err %d", ret);
fwnode_handle_put(child);
return ret;
}
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 void cr0014114_remove(struct spi_device *spi)
{
struct cr0014114 *priv = spi_get_drvdata(spi);
cancel_delayed_work_sync(&priv->work);
mutex_destroy(&priv->lock);
}
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 <[email protected]>");
MODULE_DESCRIPTION("cr0014114 LED driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("spi:cr0014114");
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