From: Michał Mirosław mirq-linux@rere.qmqm.pl
commit d12e3aae160fb26b534c4496b211d6e60a5179ed upstream.
Driver was not disabling TXRDY interrupt after last TX byte. This caused interrupt storm until transfer timeouts for slow or broken device on the bus. The patch fixes the interrupt storm on my SAMA5D2-based board.
Cc: stable@vger.kernel.org # 5.2.x [v5.2 introduced file split; the patch should apply to i2c-at91.c before the split] Fixes: fac368a04048 ("i2c: at91: add new driver") Signed-off-by: Michał Mirosław mirq-linux@rere.qmqm.pl Acked-by: Ludovic Desroches ludovic.desroches@microchip.com Tested-by: Raag Jadav raagjadav@gmail.com Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/i2c/busses/i2c-at91-master.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/i2c/busses/i2c-at91-master.c +++ b/drivers/i2c/busses/i2c-at91-master.c @@ -122,9 +122,11 @@ static void at91_twi_write_next_byte(str writeb_relaxed(*dev->buf, dev->base + AT91_TWI_THR);
/* send stop when last byte has been written */ - if (--dev->buf_len == 0) + if (--dev->buf_len == 0) { if (!dev->use_alt_cmd) at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP); + at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_TXRDY); + }
dev_dbg(dev->dev, "wrote 0x%x, to go %zu\n", *dev->buf, dev->buf_len);
@@ -542,9 +544,8 @@ static int at91_do_twi_transfer(struct a } else { at91_twi_write_next_byte(dev); at91_twi_write(dev, AT91_TWI_IER, - AT91_TWI_TXCOMP | - AT91_TWI_NACK | - AT91_TWI_TXRDY); + AT91_TWI_TXCOMP | AT91_TWI_NACK | + (dev->buf_len ? AT91_TWI_TXRDY : 0)); } }