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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 10:33:21 +0100
commit0d852fe4d27fa82de9fdcbda9a5ac634800b1fd1 (patch)
tree9f0c3e40dd2e3cf12fd35ae6a9fcfac1e0ce3943 /drivers/i2c
parent77b67063bb6bce6d475e910d3b886a606d0d91f7 (diff)
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 aa59a254be2..c02bf208084 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) {