lede/target/linux/bcm27xx/patches-6.12/950-0268-i2c-bcm2835-Make-clock-stretch-timeout-configurable.patch
=?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= d81c03f05e bcm27xx: add 6.12 patches from RPi repo
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>
2025-06-20 17:01:06 +08:00

45 lines
1.5 KiB
Diff

From a1c7a8e20c3162cd42eb62f16670ff66d76a031d Mon Sep 17 00:00:00 2001
From: Alex Crawford <raspberrypi/linux@code.acrawford.com>
Date: Fri, 28 Jan 2022 13:36:51 -0800
Subject: [PATCH] i2c: bcm2835: Make clock-stretch timeout configurable
The default clock-stretch timeout is 35 mS, which works well for
SMBus, but there are some I2C devices which can stretch the clock even
longer. Rather than trying to prescribe a safe default for everyone,
allow the timeout to be configured.
Signed-off-by: Alex Crawford <raspberrypi/linux@code.acrawford.com>
---
drivers/i2c/busses/i2c-bcm2835.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -60,6 +60,10 @@ static unsigned int debug;
module_param(debug, uint, 0644);
MODULE_PARM_DESC(debug, "1=err, 2=isr, 3=xfer");
+static unsigned int clk_tout_ms = 35; /* SMBUs-recommended 35ms */
+module_param(clk_tout_ms, uint, 0644);
+MODULE_PARM_DESC(clk_tout_ms, "clock-stretch timeout (mS)");
+
#define BCM2835_DEBUG_MAX 512
struct bcm2835_debug {
struct i2c_msg *msg;
@@ -219,12 +223,12 @@ static int clk_bcm2835_i2c_set_rate(stru
(redl << BCM2835_I2C_REDL_SHIFT));
/*
- * Set the clock stretch timeout to the SMBUs-recommended 35ms.
+ * Set the clock stretch timeout.
*/
- if (rate > 0xffff*1000/35)
+ if (rate > 0xffff*1000/clk_tout_ms)
clk_tout = 0xffff;
else
- clk_tout = 35*rate/1000;
+ clk_tout = clk_tout_ms*rate/1000;
bcm2835_i2c_writel(div->i2c_dev, BCM2835_I2C_CLKT, clk_tout);