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