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authorLudovic Desroches <ludovic.desroches@atmel.com>2012-11-13 16:43:21 +0100
committerWolfram Sang <w.sang@pengutronix.de>2012-11-14 10:28:28 +0100
commit7c3fe64d133fbe4132d9966cd2f79a7193f13139 (patch)
tree645548bacfc35cfbbcef07dd124399b45db0e880 /drivers/i2c
parent58a7371a4dd9d03f77265ee2784781fc39096136 (diff)
downloadop-kernel-dev-7c3fe64d133fbe4132d9966cd2f79a7193f13139.zip
op-kernel-dev-7c3fe64d133fbe4132d9966cd2f79a7193f13139.tar.gz
i2c: at91: fix SMBus quick command
The driver claims to support SMBus quick command but it was not the case. This patch fixes this issue. Without it, i2cdetect finds imaginary devices. And with some IP versions, trying to send 0 byte can cause issue when writing data to an EEPROM. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> [wsa: improved the commit message] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-at91.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index aa59a25..c02bf20 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -39,6 +39,7 @@
#define AT91_TWI_STOP 0x0002 /* Send a Stop Condition */
#define AT91_TWI_MSEN 0x0004 /* Master Transfer Enable */
#define AT91_TWI_SVDIS 0x0020 /* Slave Transfer Disable */
+#define AT91_TWI_QUICK 0x0040 /* SMBus quick command */
#define AT91_TWI_SWRST 0x0080 /* Software Reset */
#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
@@ -212,7 +213,11 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev)
INIT_COMPLETION(dev->cmd_complete);
dev->transfer_status = 0;
- if (dev->msg->flags & I2C_M_RD) {
+
+ if (!dev->buf_len) {
+ at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
+ at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
+ } else if (dev->msg->flags & I2C_M_RD) {
unsigned start_flags = AT91_TWI_START;
if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
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