On Thu, Aug 21, 2014 at 10:04:31PM +0400, Sergei Shtylyov wrote: > Hello. > > On 08/21/2014 09:50 PM, Addy Ke wrote: > > >In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data > >in one transaction, so the size of data to be write/read to/from > >TXDATAx/RXDATAx must be less than or equal 32 bytes at a time. > > >Test on pinky board, elan receive 158 bytes data. > > >Signed-off-by: Addy Ke <addy...@rock-chips.com> > >--- > > drivers/i2c/busses/i2c-rk3x.c | 3 +++ > > 1 file changed, 3 insertions(+) > > >diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c > >index 69e1185..dc0aa64 100644 > >--- a/drivers/i2c/busses/i2c-rk3x.c > >+++ b/drivers/i2c/busses/i2c-rk3x.c > >@@ -323,6 +323,9 @@ static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, > >unsigned int ipd) > > /* ack interrupt */ > > i2c_writel(i2c, REG_INT_MBRF, REG_IPD); > > > >+ /* Can only handle a maximum of 32 bytes at a time */ > >+ len = (len > 32) ? 32 : len; > > Why not min(len, 32)? Or even: > > if (len > 32) > len = 32;
No silent trimming, please. The message should be rejected when the transfer is set up. We could assign -EOVERFLOW to that type of failures, so users will know. Sadly, I have seen other controllers having such limits :(
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