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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: fac368a040 ("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>
This commit is contained in:
Michał Mirosław 2019-07-22 20:55:27 +02:00 committed by Wolfram Sang
parent fd01eecdf9
commit d12e3aae16
1 changed files with 5 additions and 4 deletions
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9
drivers/i2c/busses/i2c-at91-master.c
View File

@ -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));
}
}