8f9e91ad03
These patches were generated from: https://github.com/raspberrypi/linux/commits/rpi-6.12.y With the following command: git format-patch -N v6.12.27..HEAD (HEAD -> 8d3206ee456a5ecdf9ddbfd8e5e231e4f0cd716e) Exceptions: - (def)configs patches - github workflows patches - applied & reverted patches - readme patches - wireless patches Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
70 lines
2 KiB
Diff
70 lines
2 KiB
Diff
From a649152e16d5ca0714d3959fa38ed1ae639ff179 Mon Sep 17 00:00:00 2001
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From: Dave Stevenson <dave.stevenson@raspberrypi.com>
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Date: Fri, 17 May 2024 14:27:59 +0100
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Subject: [PATCH] regulator: rpi_panel_v2: Add delay on I2C reads
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As with many microcontrollers, the panel wants to use clock
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stretching during a read so that the appropriate return value
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can be generated and programmed into the hardware.
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With Pi0-3 really not supporting clock stretching, this resulted
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in the panel firmware dying.
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Insert a delay between the write and the read to give the firmware
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a chance to generate the relevant return value.
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Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
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---
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drivers/regulator/rpi-panel-v2-regulator.c | 35 +++++++++++++++++++++-
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1 file changed, 34 insertions(+), 1 deletion(-)
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--- a/drivers/regulator/rpi-panel-v2-regulator.c
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+++ b/drivers/regulator/rpi-panel-v2-regulator.c
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@@ -87,6 +87,39 @@ static const struct backlight_ops rpi_pa
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.update_status = rpi_panel_v2_update_status,
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};
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+static int rpi_panel_v2_i2c_read(struct i2c_client *client, u8 reg, unsigned int *buf)
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+{
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+ struct i2c_msg msgs[1];
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+ u8 addr_buf[1] = { reg };
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+ u8 data_buf[1] = { 0, };
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+ int ret;
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+
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+ /* Write register address */
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+ msgs[0].addr = client->addr;
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+ msgs[0].flags = 0;
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+ msgs[0].len = ARRAY_SIZE(addr_buf);
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+ msgs[0].buf = addr_buf;
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+
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+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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+ if (ret != ARRAY_SIZE(msgs))
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+ return -EIO;
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+
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+ usleep_range(5000, 10000);
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+
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+ /* Read data from register */
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+ msgs[0].addr = client->addr;
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+ msgs[0].flags = I2C_M_RD;
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+ msgs[0].len = 1;
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+ msgs[0].buf = data_buf;
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+
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+ ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
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+ if (ret != ARRAY_SIZE(msgs))
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+ return -EIO;
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+
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+ *buf = data_buf[0];
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+ return 0;
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+}
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+
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/*
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* I2C driver interface functions
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*/
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@@ -114,7 +147,7 @@ static int rpi_panel_v2_i2c_probe(struct
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goto error;
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}
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- ret = regmap_read(regmap, REG_ID, &data);
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+ ret = rpi_panel_v2_i2c_read(i2c, REG_ID, &data);
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if (ret < 0) {
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dev_err(&i2c->dev, "Failed to read REG_ID reg: %d\n", ret);
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goto error;
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