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Commit d12e3aae authored by Michał Mirosław's avatar Michał Mirosław Committed by Wolfram Sang
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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: fac368a0 ("i2c: at91: add new driver")
Signed-off-by: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: default avatarLudovic Desroches <ludovic.desroches@microchip.com>
Tested-by: default avatarRaag Jadav <raagjadav@gmail.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent fd01eecd

drivers/i2c/busses/i2c-at91-master.c

+5 −4
Original line number Diff line number Diff line
@@ -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));

		}

	}