google/trogdor: Add backlight support for Parade ps8640

Add backlight support in ps8640 through the AUX channel using eDP
DPCD registers.

BUG=b:202966352
BRANCH=trogdor
TEST=verified firmware screen works on homestar rev4

Change-Id: Ief1bf56c89c8215427dcbddfc67e8bcd4c3607d2
Signed-off-by: xuxinxiong <xuxinxiong@huaqin.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/58624
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 99 insertions, 1 deletions

diff --git a/src/drivers/parade/ps8640/ps8640.c b/src/drivers/parade/ps8640/ps8640.c
index 93121f2094..587eae1d9c 100644
--- a/src/drivers/parade/ps8640/ps8640.c
+++ b/src/drivers/parade/ps8640/ps8640.c
@@ -5,7 +5,7 @@
 #include <edid.h>
 #include <console/console.h>
 #include <timer.h>
-
+#include <dp_aux.h>
 #include "ps8640.h"
 
 int ps8640_get_edid(uint8_t bus, uint8_t chip, struct edid *out)
@@ -80,3 +80,101 @@ int ps8640_init(uint8_t bus, uint8_t chip)
 
 	return 0;
 }
+
+static cb_err_t ps8640_bridge_aux_request(uint8_t bus,
+					  uint8_t chip,
+					  unsigned int target_reg,
+					  unsigned int total_size,
+					  enum aux_request request,
+					  uint8_t *data)
+{
+	int i;
+	uint32_t length;
+	uint8_t buf;
+	uint8_t reg;
+	int ret;
+
+	if (target_reg & ~SWAUX_ADDR_MASK)
+		return CB_ERR;
+
+	while (total_size) {
+		length = MIN(total_size, DP_AUX_MAX_PAYLOAD_BYTES);
+		total_size -= length;
+
+		ret = i2c_writeb(bus, chip, PAGE0_AUXCH_CFG3, AUXCH_CFG3_RESET);
+		if (ret)
+			return CB_ERR;
+
+		enum i2c_over_aux cmd = dp_get_aux_cmd(request, total_size);
+		if (i2c_writeb(bus, chip, PAGE0_SWAUX_ADDR_23_16,
+			(target_reg >> 16) | (cmd << 4)) ||
+		    i2c_writeb(bus, chip, PAGE0_SWAUX_ADDR_15_8, target_reg >> 8) ||
+		    i2c_writeb(bus, chip, PAGE0_SWAUX_ADDR_7_0, target_reg)) {
+			return CB_ERR;
+		}
+
+		if (dp_aux_request_is_write(request)) {
+			reg = PAGE0_SWAUX_WDATA;
+			for (i = 0; i < length; i++) {
+				ret = i2c_writeb(bus, chip, reg++, *data++);
+				if (ret)
+					return CB_ERR;
+			}
+		} else {
+			if (length == 0)
+				i2c_writeb(bus, chip, PAGE0_SWAUX_LENGTH, SWAUX_NO_PAYLOAD);
+			else
+				i2c_writeb(bus, chip, PAGE0_SWAUX_LENGTH, length - 1);
+		}
+
+		ret = i2c_writeb(bus, chip, PAGE0_SWAUX_CTRL, SWAUX_SEND);
+		if (ret)
+			return CB_ERR;
+
+		if (!wait_ms(100, !i2c_readb(bus, chip, PAGE0_SWAUX_CTRL, &buf) &&
+				  !(buf & SWAUX_SEND)))
+			return CB_ERR;
+
+		if (i2c_readb(bus, chip, PAGE0_SWAUX_STATUS, &buf))
+			return CB_ERR;
+
+		switch (buf & SWAUX_STATUS_MASK) {
+		case SWAUX_STATUS_NACK:
+		case SWAUX_STATUS_I2C_NACK:
+		case SWAUX_STATUS_INVALID:
+		case SWAUX_STATUS_TIMEOUT:
+			return CB_ERR;
+		case SWAUX_STATUS_ACKM:
+			length = buf & SWAUX_M_MASK;
+			break;
+		}
+
+		if (length && !dp_aux_request_is_write(request)) {
+			reg = PAGE0_SWAUX_RDATA;
+			for (i = 0; i < length; i++) {
+				if (i2c_readb(bus, chip, reg++, &buf))
+					return CB_ERR;
+				*data++ = buf;
+			}
+		}
+	}
+
+	return CB_SUCCESS;
+}
+
+void ps8640_backlight_enable(uint8_t bus, uint8_t chip)
+{
+	uint8_t val;
+
+	val = DP_BACKLIGHT_CONTROL_MODE_DPCD;
+	ps8640_bridge_aux_request(bus, chip, DP_BACKLIGHT_MODE_SET, 1,
+				  DPCD_WRITE, &val);
+
+	val = 0xff;
+	ps8640_bridge_aux_request(bus, chip, DP_BACKLIGHT_BRIGHTNESS_MSB, 1,
+				  DPCD_WRITE, &val);
+
+	val = DP_BACKLIGHT_ENABLE;
+	ps8640_bridge_aux_request(bus, chip, DP_DISPLAY_CONTROL_REGISTER, 1,
+				  DPCD_WRITE, &val);
+}