ps862x.c
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/*
* Copyright (C) 2015 Google, Inc
* Written by Simon Glass <sjg@chromium.org>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <i2c.h>
#include <video_bridge.h>
#include <power/regulator.h>
DECLARE_GLOBAL_DATA_PTR;
/*
* Initialisation of the chip is a process of writing certain values into
* certain registers over i2c bus. The chip in fact responds to a range of
* addresses on the i2c bus, so for each written value three parameters are
* required: i2c address, register address and the actual value.
*
* The base address is derived from the device tree, but oddly the chip
* responds on several addresses with different register sets for each.
*/
/**
* ps8622_write() Write a PS8622 eDP bridge i2c register
*
* @param dev I2C device
* @param addr_off offset from the i2c base address for ps8622
* @param reg_addr register address to write
* @param value value to be written
* @return 0 on success, non-0 on failure
*/
static int ps8622_write(struct udevice *dev, unsigned addr_off,
unsigned char reg_addr, unsigned char value)
{
struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
uint8_t buf[2];
struct i2c_msg msg;
int ret;
msg.addr = chip->chip_addr + addr_off;
msg.flags = 0;
buf[0] = reg_addr;
buf[1] = value;
msg.buf = buf;
msg.len = 2;
ret = dm_i2c_xfer(dev, &msg, 1);
if (ret) {
debug("%s: write failed, reg=%#x, value=%#x, ret=%d\n",
__func__, reg_addr, value, ret);
return ret;
}
return 0;
}
static int ps8622_set_backlight(struct udevice *dev, int percent)
{
int level = percent * 255 / 100;
debug("%s: level=%d\n", __func__, level);
return ps8622_write(dev, 0x01, 0xa7, level);
}
static int ps8622_attach(struct udevice *dev)
{
const uint8_t *params;
struct udevice *reg;
int ret, i, len;
debug("%s: %s\n", __func__, dev->name);
/* set the LDO providing the 1.2V rail to the Parade bridge */
ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
"power-supply", ®);
if (!ret) {
ret = regulator_autoset(reg);
} else if (ret != -ENOENT) {
debug("%s: Failed to enable power: ret=%d\n", __func__, ret);
return ret;
}
ret = video_bridge_set_active(dev, true);
if (ret)
return ret;
params = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), "parade,regs",
&len);
if (!params || len % 3) {
debug("%s: missing/invalid params=%p, len=%x\n", __func__,
params, len);
return -EINVAL;
}
/* need to wait 20ms after power on before doing I2C writes */
mdelay(20);
for (i = 0; i < len; i += 3) {
ret = ps8622_write(dev, params[i + 0], params[i + 1],
params[i + 2]);
if (ret)
return ret;
}
return 0;
}
static int ps8622_probe(struct udevice *dev)
{
debug("%s\n", __func__);
if (device_get_uclass_id(dev->parent) != UCLASS_I2C)
return -EPROTONOSUPPORT;
return 0;
}
struct video_bridge_ops ps8622_ops = {
.attach = ps8622_attach,
.set_backlight = ps8622_set_backlight,
};
static const struct udevice_id ps8622_ids[] = {
{ .compatible = "parade,ps8622", },
{ .compatible = "parade,ps8625", },
{ }
};
U_BOOT_DRIVER(parade_ps8622) = {
.name = "parade_ps8622",
.id = UCLASS_VIDEO_BRIDGE,
.of_match = ps8622_ids,
.probe = ps8622_probe,
.ops = &ps8622_ops,
};