blob: c1ba78c997058e826953e7d096a4d4e294bf9b97 [file] [log] [blame]
From 433c1cb88a219a3512692fc13d3c4038cc133cea 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
commit 02e64276c6dbcc4c5f39844f33d18180832a58f3 upstream.
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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
index 3d90c0bb049e..25572fd63a4c 100644
--- a/drivers/i2c/busses/i2c-stm32f7.c
+++ b/drivers/i2c/busses/i2c-stm32f7.c
@@ -1189,6 +1189,8 @@ 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);
--
2.7.4