mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-21 06:33:41 +00:00
8299d1f057
Rebased RPi foundation patches on linux 5.10.59, removed applied and reverted patches, wireless patches and defconfig patches. bcm2708: boot tested on RPi B+ v1.2 bcm2709: boot tested on RPi 4B v1.1 4G bcm2711: boot tested on RPi 4B v1.1 4G Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
59 lines
1.9 KiB
Diff
59 lines
1.9 KiB
Diff
From 3ad3a680ece56c7134d9500a0413b4f9259c07d8 Mon Sep 17 00:00:00 2001
|
|
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
|
|
Date: Thu, 23 Apr 2020 10:17:18 +0100
|
|
Subject: [PATCH] drm/panel/raspberrypi-touchscreen: Use independent
|
|
I2C actions with delay.
|
|
|
|
We now have the hardware I2C controller pinmuxed to the drive the
|
|
display I2C, but this controller does not support clock stretching.
|
|
The Atmel micro-controller in the panel requires clock stretching
|
|
to allow it to prepare any data to be read.
|
|
|
|
Split the rpi_touchscreen_i2c_read into two independent transactions with
|
|
a delay between them for the Atmel to prepare the data.
|
|
|
|
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
|
|
---
|
|
.../drm/panel/panel-raspberrypi-touchscreen.c | 30 ++++++++++++++++++-
|
|
1 file changed, 29 insertions(+), 1 deletion(-)
|
|
|
|
--- a/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
|
|
+++ b/drivers/gpu/drm/panel/panel-raspberrypi-touchscreen.c
|
|
@@ -219,7 +219,35 @@ static struct rpi_touchscreen *panel_to_
|
|
|
|
static int rpi_touchscreen_i2c_read(struct rpi_touchscreen *ts, u8 reg)
|
|
{
|
|
- return i2c_smbus_read_byte_data(ts->i2c, reg);
|
|
+ struct i2c_client *client = ts->i2c;
|
|
+ struct i2c_msg msgs[1];
|
|
+ u8 addr_buf[1] = { reg };
|
|
+ u8 data_buf[1] = { 0, };
|
|
+ int ret;
|
|
+
|
|
+ /* Write register address */
|
|
+ msgs[0].addr = client->addr;
|
|
+ msgs[0].flags = 0;
|
|
+ msgs[0].len = ARRAY_SIZE(addr_buf);
|
|
+ msgs[0].buf = addr_buf;
|
|
+
|
|
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
|
|
+ if (ret != ARRAY_SIZE(msgs))
|
|
+ return -EIO;
|
|
+
|
|
+ usleep_range(100, 300);
|
|
+
|
|
+ /* Read data from register */
|
|
+ msgs[0].addr = client->addr;
|
|
+ msgs[0].flags = I2C_M_RD;
|
|
+ msgs[0].len = 1;
|
|
+ msgs[0].buf = data_buf;
|
|
+
|
|
+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
|
|
+ if (ret != ARRAY_SIZE(msgs))
|
|
+ return -EIO;
|
|
+
|
|
+ return data_buf[0];
|
|
}
|
|
|
|
static void rpi_touchscreen_i2c_write(struct rpi_touchscreen *ts,
|