From: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
The driver claims to support SMBus quick command but it was not the case.
This patch fixes this issue.
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
---
Hi Wolfram,
Thanks to Jean explanation about i2cdetect and eeprom behavior, I realized
that the first version of the patch was incorrect. This time all the i2c
devices are detected with i2cdetect -q.
I hope this fix could go into 3.7 since the driver claims SMBus quick
capability but it doesn't support it. Moreover without it i2cdetect find
imaginary devices, and with some IP versions, trying to send 0 byte can cause
issue when writing data to an EEPROM.
Regards
Ludovic
Changes since v1:
* enable txcomp irq to have a correct behavior
drivers/i2c/busses/i2c-at91.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index f471747..e9c926c 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -44,6 +44,7 @@
#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 */
@@ -386,7 +387,11 @@ 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) {
--
1.7.11.3
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
