From c304e1a5fbfb1dde63d55263a8a7b01bb1a70add Mon Sep 17 00:00:00 2001 From: =?utf8?q?Micha=C5=82=20Miros=C5=82aw?= Date: Mon, 22 Jul 2019 20:55:27 +0200 Subject: [PATCH] i2c: at91: disable TXRDY interrupt after sending data MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Acked-by: Ludovic Desroches Tested-by: Raag Jadav Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-at91-master.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) 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)); } } -- 2.51.0