From 02e64276c6dbcc4c5f39844f33d18180832a58f3 Mon Sep 17 00:00:00 2001
From: Fabrice Gasnier <fabrice.gasnier@st.com>
Date: Mon, 30 Sep 2019 17:28:01 +0200
Subject: [PATCH] i2c: stm32f7: fix first byte to send in slave mode
Git-commit: 02e64276c6dbcc4c5f39844f33d18180832a58f3
Patch-mainline: v5.4-rc5
References: git-fixes bnc#1151927 5.3.10
The slave-interface documentation [1] states "the bus driver should
transmit the first byte" upon I2C_SLAVE_READ_REQUESTED slave event:
- 'val': backend returns first byte to be sent
The driver currently ignores the 1st byte to send on this event.
[1] https://www.kernel.org/doc/Documentation/i2c/slave-interface
Fixes: 60d609f30de2 ("i2c: i2c-stm32f7: Add slave support")
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/i2c/busses/i2c-stm32f7.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index d36cf08461f7..c8ce6c8dd404 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -1192,6 +1192,8 @@ static void stm32f7_i2c_slave_start(struct stm32f7_i2c_dev *i2c_dev)
STM32F7_I2C_CR1_TXIE;
stm32f7_i2c_set_bits(base + STM32F7_I2C_CR1, mask);
+ /* Write 1st data byte */
+ writel_relaxed(value, base + STM32F7_I2C_TXDR);
} else {
/* Notify i2c slave that new write transfer is starting */
i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
--
2.16.4