From: Michał Mirosław Date: Mon, 22 Jul 2019 18:55:27 +0000 (+0200) Subject: i2c: at91: disable TXRDY interrupt after sending data X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=d12e3aae160fb26b534c4496b211d6e60a5179ed;p=linux.git i2c: at91: disable TXRDY interrupt after sending data 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 Acked-by: Ludovic Desroches Tested-by: Raag Jadav Signed-off-by: Wolfram Sang --- diff --git a/drivers/i2c/busses/i2c-at91-master.c b/drivers/i2c/busses/i2c-at91-master.c index e87232f2e7085..a3fcc35ffd3b6 100644 --- 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(struct at91_twi_dev *dev) 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 at91_twi_dev *dev) } 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)); } }