Messages in this thread | | | Date | Fri, 21 Nov 2014 10:08:28 -0600 | From | Felipe Balbi <> | Subject | Re: [PATCH] i2c: omap: fix i207 errata handling |
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On Fri, Nov 21, 2014 at 04:16:51AM +0400, Alexander Kochetkov wrote: > commit 6d9939f651419a63e091105663821f9c7d3fec37 (i2c: omap: split out [XR]DR > and [XR]RDY) changed the way how errata i207 (I2C: RDR Flag May Be Incorrectly > Set) get handled. 6d9939f6514 code doesn't correspond to workaround provided by > errata. > > According to errata ISR must filter out spurious RDR before data read not after. > ISR must read RXSTAT to get number of bytes available to read. Because RDR > could be set while there could no data in the receive FIFO. > > Restored pre 6d9939f6514 way of handling errata. > > Found by code review. Real impact haven't seen. > Tested on Beagleboard XM C. > > Signed-off-by: Alexander Kochetkov <al.kochet@gmail.com> > Fixes: 6d9939f651419a63e09110 i2c: omap: split out [XR]DR and [XR]RDY
Tested on BBB and AM437x Starter Kit
Tested-by: Felipe Balbi <balbi@ti.com> Reviewed-by: Felipe Balbi <balbi@ti.com>
> --- > drivers/i2c/busses/i2c-omap.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index 90dcc2e..e7cbcb0 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -958,11 +958,13 @@ omap_i2c_isr_thread(int this_irq, void *dev_id) > if (dev->fifo_size) > num_bytes = dev->buf_len; > > - omap_i2c_receive_data(dev, num_bytes, true); > - > - if (dev->errata & I2C_OMAP_ERRATA_I207) > + if (dev->errata & I2C_OMAP_ERRATA_I207) { > i2c_omap_errata_i207(dev, stat); > + num_bytes = (omap_i2c_read_reg(dev, > + OMAP_I2C_BUFSTAT_REG) >> 8) & 0x3F; > + } > > + omap_i2c_receive_data(dev, num_bytes, true); > omap_i2c_ack_stat(dev, OMAP_I2C_STAT_RDR); > continue; > } > -- > 1.7.9.5 >
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