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authorMatt Weber <matthew.weber@rockwellcollins.com>2017-06-22 15:00:33 -0500
committerWolfram Sang <wsa@the-dreams.de>2017-06-23 20:56:21 +0200
commit8064c616984eaa015f018dba595d78cd24a0cc8c (patch)
treef5786d9aac081c10a277b5d1a7c7060f9c5ea181 /drivers/i2c
parent9615a01f71ca02858f5265b1b545280758562aa2 (diff)
downloadlinux-8064c616984eaa015f018dba595d78cd24a0cc8c.tar.bz2
i2c: cadance: fix ctrl/addr reg write order
The driver was clearing the hold bit in the control register before writing to the address register which resulted in a stop condition being generated rather than a repeated start. This issue was only observed when a system was running much slower than a normal processor would execute. The IP data sheet mentions a ordering of writing to the address register before clearing the hold. Fixes: df8eb5691c4 ("i2c: Add driver for Cadence I2C controller") Signed-off-by: John Linn <john.linn@xilinx.com> Signed-off-by: Paresh Chaudhary <paresh.chaudhary@rockwellcollins.com> Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-cadence.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 45d6771fac8c..75d80161931f 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -405,14 +405,14 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
cdns_i2c_writereg(id->recv_count, CDNS_I2C_XFER_SIZE_OFFSET);
}
+ /* Set the slave address in address register - triggers operation */
+ cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
+ CDNS_I2C_ADDR_OFFSET);
/* Clear the bus hold flag if bytes to receive is less than FIFO size */
if (!id->bus_hold_flag &&
((id->p_msg->flags & I2C_M_RECV_LEN) != I2C_M_RECV_LEN) &&
(id->recv_count <= CDNS_I2C_FIFO_DEPTH))
cdns_i2c_clear_bus_hold(id);
- /* Set the slave address in address register - triggers operation */
- cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
- CDNS_I2C_ADDR_OFFSET);
cdns_i2c_writereg(CDNS_I2C_ENABLED_INTR_MASK, CDNS_I2C_IER_OFFSET);
}