1 /* 2 * Copyright (C) 2015 Google, Inc 3 * Written by Simon Glass <sjg@chromium.org> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 8 #include <common.h> 9 #include <dm.h> 10 #include <errno.h> 11 #include <i2c.h> 12 #include <video_bridge.h> 13 #include <power/regulator.h> 14 15 DECLARE_GLOBAL_DATA_PTR; 16 17 /* 18 * Initialisation of the chip is a process of writing certain values into 19 * certain registers over i2c bus. The chip in fact responds to a range of 20 * addresses on the i2c bus, so for each written value three parameters are 21 * required: i2c address, register address and the actual value. 22 * 23 * The base address is derived from the device tree, but oddly the chip 24 * responds on several addresses with different register sets for each. 25 */ 26 27 /** 28 * ps8622_write() Write a PS8622 eDP bridge i2c register 29 * 30 * @param dev I2C device 31 * @param addr_off offset from the i2c base address for ps8622 32 * @param reg_addr register address to write 33 * @param value value to be written 34 * @return 0 on success, non-0 on failure 35 */ 36 static int ps8622_write(struct udevice *dev, unsigned addr_off, 37 unsigned char reg_addr, unsigned char value) 38 { 39 struct dm_i2c_chip *chip = dev_get_parent_platdata(dev); 40 uint8_t buf[2]; 41 struct i2c_msg msg; 42 int ret; 43 44 msg.addr = chip->chip_addr + addr_off; 45 msg.flags = 0; 46 buf[0] = reg_addr; 47 buf[1] = value; 48 msg.buf = buf; 49 msg.len = 2; 50 ret = dm_i2c_xfer(dev, &msg, 1); 51 if (ret) { 52 debug("%s: write failed, reg=%#x, value=%#x, ret=%d\n", 53 __func__, reg_addr, value, ret); 54 return ret; 55 } 56 57 return 0; 58 } 59 60 static int ps8622_set_backlight(struct udevice *dev, int percent) 61 { 62 int level = percent * 255 / 100; 63 64 debug("%s: level=%d\n", __func__, level); 65 return ps8622_write(dev, 0x01, 0xa7, level); 66 } 67 68 static int ps8622_attach(struct udevice *dev) 69 { 70 const uint8_t *params; 71 struct udevice *reg; 72 int ret, i, len; 73 74 debug("%s: %s\n", __func__, dev->name); 75 /* set the LDO providing the 1.2V rail to the Parade bridge */ 76 ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev, 77 "power-supply", ®); 78 if (!ret) { 79 ret = regulator_autoset(reg); 80 } else if (ret != -ENOENT) { 81 debug("%s: Failed to enable power: ret=%d\n", __func__, ret); 82 return ret; 83 } 84 85 ret = video_bridge_set_active(dev, true); 86 if (ret) 87 return ret; 88 89 params = fdt_getprop(gd->fdt_blob, dev->of_offset, "parade,regs", &len); 90 if (!params || len % 3) { 91 debug("%s: missing/invalid params=%p, len=%x\n", __func__, 92 params, len); 93 return -EINVAL; 94 } 95 96 /* need to wait 20ms after power on before doing I2C writes */ 97 mdelay(20); 98 for (i = 0; i < len; i += 3) { 99 ret = ps8622_write(dev, params[i + 0], params[i + 1], 100 params[i + 2]); 101 if (ret) 102 return ret; 103 } 104 105 return 0; 106 } 107 108 static int ps8622_probe(struct udevice *dev) 109 { 110 debug("%s\n", __func__); 111 if (device_get_uclass_id(dev->parent) != UCLASS_I2C) 112 return -EPROTONOSUPPORT; 113 114 return 0; 115 } 116 117 struct video_bridge_ops ps8622_ops = { 118 .attach = ps8622_attach, 119 .set_backlight = ps8622_set_backlight, 120 }; 121 122 static const struct udevice_id ps8622_ids[] = { 123 { .compatible = "parade,ps8622", }, 124 { .compatible = "parade,ps8625", }, 125 { } 126 }; 127 128 U_BOOT_DRIVER(parade_ps8622) = { 129 .name = "parade_ps8622", 130 .id = UCLASS_VIDEO_BRIDGE, 131 .of_match = ps8622_ids, 132 .probe = ps8622_probe, 133 .ops = &ps8622_ops, 134 }; 135