mirror of
https://github.com/torvalds/linux.git
synced 2024-12-01 16:41:39 +00:00
25458b2a40
There is no code that uses ID table directly, except the struct device_driver at the end of the file. Hence, move table closer to its user. It's always possible to access them via a pointer. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20240606173037.3091598-7-andriy.shevchenko@linux.intel.com Signed-off-by: Lee Jones <lee@kernel.org>
137 lines
4.1 KiB
C
137 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
// Copyright (c) 2019 Christian Mauderer <oss@c-mauderer.de>
|
|
|
|
/*
|
|
* The driver supports controllers with a very simple SPI protocol:
|
|
* - one LED is controlled by a single byte on MOSI
|
|
* - the value of the byte gives the brightness between two values (lowest to
|
|
* highest)
|
|
* - no return value is necessary (no MISO signal)
|
|
*
|
|
* The value for minimum and maximum brightness depends on the device
|
|
* (compatible string).
|
|
*
|
|
* Supported devices:
|
|
* - "ubnt,acb-spi-led": Microcontroller (SONiX 8F26E611LA) based device used
|
|
* for example in Ubiquiti airCube ISP. Reverse engineered protocol for this
|
|
* controller:
|
|
* * Higher two bits set a mode. Lower six bits are a parameter.
|
|
* * Mode: 00 -> set brightness between 0x00 (min) and 0x3F (max)
|
|
* * Mode: 01 -> pulsing pattern (min -> max -> min) with an interval. From
|
|
* some tests, the period is about (50ms + 102ms * parameter). There is a
|
|
* slightly different pattern starting from 0x10 (longer gap between the
|
|
* pulses) but the time still follows that calculation.
|
|
* * Mode: 10 -> same as 01 but with only a ramp from min to max. Again a
|
|
* slight jump in the pattern at 0x10.
|
|
* * Mode: 11 -> blinking (off -> 25% -> off -> 25% -> ...) with a period of
|
|
* (105ms * parameter)
|
|
* NOTE: This driver currently only supports mode 00.
|
|
*/
|
|
|
|
#include <linux/leds.h>
|
|
#include <linux/mod_devicetable.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/property.h>
|
|
#include <linux/spi/spi.h>
|
|
#include <uapi/linux/uleds.h>
|
|
|
|
struct spi_byte_chipdef {
|
|
/* SPI byte that will be send to switch the LED off */
|
|
u8 off_value;
|
|
/* SPI byte that will be send to switch the LED to maximum brightness */
|
|
u8 max_value;
|
|
};
|
|
|
|
struct spi_byte_led {
|
|
struct led_classdev ldev;
|
|
struct spi_device *spi;
|
|
char name[LED_MAX_NAME_SIZE];
|
|
struct mutex mutex;
|
|
const struct spi_byte_chipdef *cdef;
|
|
};
|
|
|
|
static const struct spi_byte_chipdef ubnt_acb_spi_led_cdef = {
|
|
.off_value = 0x0,
|
|
.max_value = 0x3F,
|
|
};
|
|
|
|
static int spi_byte_brightness_set_blocking(struct led_classdev *dev,
|
|
enum led_brightness brightness)
|
|
{
|
|
struct spi_byte_led *led = container_of(dev, struct spi_byte_led, ldev);
|
|
u8 value;
|
|
int ret;
|
|
|
|
value = (u8) brightness + led->cdef->off_value;
|
|
|
|
mutex_lock(&led->mutex);
|
|
ret = spi_write(led->spi, &value, sizeof(value));
|
|
mutex_unlock(&led->mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int spi_byte_probe(struct spi_device *spi)
|
|
{
|
|
struct fwnode_handle *child __free(fwnode_handle) = NULL;
|
|
struct device *dev = &spi->dev;
|
|
struct spi_byte_led *led;
|
|
struct led_init_data init_data = {};
|
|
enum led_default_state state;
|
|
int ret;
|
|
|
|
if (device_get_child_node_count(dev) != 1) {
|
|
dev_err(dev, "Device must have exactly one LED sub-node.");
|
|
return -EINVAL;
|
|
}
|
|
|
|
led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
|
|
if (!led)
|
|
return -ENOMEM;
|
|
|
|
ret = devm_mutex_init(dev, &led->mutex);
|
|
if (ret)
|
|
return ret;
|
|
|
|
led->spi = spi;
|
|
led->cdef = device_get_match_data(dev);
|
|
led->ldev.brightness = LED_OFF;
|
|
led->ldev.max_brightness = led->cdef->max_value - led->cdef->off_value;
|
|
led->ldev.brightness_set_blocking = spi_byte_brightness_set_blocking;
|
|
|
|
child = device_get_next_child_node(dev, NULL);
|
|
|
|
state = led_init_default_state_get(child);
|
|
if (state == LEDS_DEFSTATE_ON)
|
|
led->ldev.brightness = led->ldev.max_brightness;
|
|
spi_byte_brightness_set_blocking(&led->ldev,
|
|
led->ldev.brightness);
|
|
|
|
init_data.fwnode = child;
|
|
init_data.devicename = "leds-spi-byte";
|
|
init_data.default_label = ":";
|
|
|
|
return devm_led_classdev_register_ext(dev, &led->ldev, &init_data);
|
|
}
|
|
|
|
static const struct of_device_id spi_byte_dt_ids[] = {
|
|
{ .compatible = "ubnt,acb-spi-led", .data = &ubnt_acb_spi_led_cdef },
|
|
{}
|
|
};
|
|
MODULE_DEVICE_TABLE(of, spi_byte_dt_ids);
|
|
|
|
static struct spi_driver spi_byte_driver = {
|
|
.probe = spi_byte_probe,
|
|
.driver = {
|
|
.name = KBUILD_MODNAME,
|
|
.of_match_table = spi_byte_dt_ids,
|
|
},
|
|
};
|
|
module_spi_driver(spi_byte_driver);
|
|
|
|
MODULE_AUTHOR("Christian Mauderer <oss@c-mauderer.de>");
|
|
MODULE_DESCRIPTION("single byte SPI LED driver");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_ALIAS("spi:leds-spi-byte");
|