diff options
Diffstat (limited to 'drivers/video')
| -rw-r--r-- | drivers/video/bridge/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/video/bridge/Makefile | 1 | ||||
| -rw-r--r-- | drivers/video/bridge/ps862x.c | 134 |
3 files changed, 145 insertions, 0 deletions
diff --git a/drivers/video/bridge/Kconfig b/drivers/video/bridge/Kconfig index 7ba6b17..589795d 100644 --- a/drivers/video/bridge/Kconfig +++ b/drivers/video/bridge/Kconfig @@ -6,3 +6,13 @@ config VIDEO_BRIDGE another. For example, where the SoC only supports eDP and the LCD requires LVDS, an eDP->LVDS bridge chip can be used to provide the necessary conversion. This option enables support for these devices. + +config VIDEO_BRIDGE_PARADE_PS862X + bool "Support Parade PS862X DP->LVDS bridge" + depends on VIDEO_BRIDGE + help + The Parade PS8622 and PS8625 are DisplayPort-to-LVDS (Low voltage + differential signalling) converters. They enable an LVDS LCD panel + to be connected to an eDP output device such as an SoC that lacks + LVDS capability, or where LVDS requires too many signals to route + on the PCB. Setup parameters are provided in the device tree. diff --git a/drivers/video/bridge/Makefile b/drivers/video/bridge/Makefile index f4bf087..c7cc563 100644 --- a/drivers/video/bridge/Makefile +++ b/drivers/video/bridge/Makefile @@ -5,3 +5,4 @@ # SPDX-License-Identifier: GPL-2.0+ obj-$(CONFIG_VIDEO_BRIDGE) += video-bridge-uclass.o +obj-$(CONFIG_VIDEO_BRIDGE_PARADE_PS862X) += ps862x.o diff --git a/drivers/video/bridge/ps862x.c b/drivers/video/bridge/ps862x.c new file mode 100644 index 0000000..80f63e3 --- /dev/null +++ b/drivers/video/bridge/ps862x.c @@ -0,0 +1,134 @@ +/* + * 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, "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, +}; |