| Message ID | 1408669991-9703-1-git-send-email-addy.ke@rock-chips.com |
|---|---|
| State | Superseded |
| Headers | show |
Addy, On Thu, Aug 21, 2014 at 6:13 PM, Addy Ke <addy.ke@rock-chips.com> wrote: > In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data > in one chunk, so the size of data to be write/read to/from TXDATAx/RXDATAx > must be less than or equal 32 bytes at a time. > > Tested on rk3288-pinky board, elan receive 158 bytes data. > > Acked-by: Max Schwarz <max.schwarz@online.de> > Signed-off-by: Addy Ke <addy.ke@rock-chips.com> > --- > Changes in v2: > - Use cleaner syntax as suggested by Sergei. > - Update commit message as suggested by Wolfram. > > Changes in v3: > - fix typo: maste --> master and double spaces after 'len' > > drivers/i2c/busses/i2c-rk3x.c | 4 ++++ > 1 file changed, 4 insertions(+) Oops, we collided in the ether. This looks good to me. Tested-by: Doug Anderson <dianders@chromium.org> -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Addy, On Fri, Aug 22, 2014 at 09:13:11AM +0800, Addy Ke wrote: > In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data > in one chunk, so the size of data to be write/read to/from TXDATAx/RXDATAx > must be less than or equal 32 bytes at a time. > > Tested on rk3288-pinky board, elan receive 158 bytes data. > > Acked-by: Max Schwarz <max.schwarz@online.de> > Signed-off-by: Addy Ke <addy.ke@rock-chips.com> > --- > Changes in v2: > - Use cleaner syntax as suggested by Sergei. > - Update commit message as suggested by Wolfram. > > Changes in v3: > - fix typo: maste --> master and double spaces after 'len' > > drivers/i2c/busses/i2c-rk3x.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c > index 69e1185..806724a 100644 > --- a/drivers/i2c/busses/i2c-rk3x.c > +++ b/drivers/i2c/busses/i2c-rk3x.c > @@ -323,6 +323,10 @@ 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 */ > + if (unlikely(len > 32)) > + len = 32; I do not think we should be using unlikely here (and in another spot in the driver): unlikely should be used only if the condition happens extremely infrequently in all of the systems. Here, if a box happens to have a device that uses transfers larger than 32 bytes we'd be hitting unlikely branch pretty often. Thanks.
diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 69e1185..806724a 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -323,6 +323,10 @@ 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 */ + if (unlikely(len > 32)) + len = 32; + /* read the data from receive buffer */ for (i = 0; i < len; ++i) { if (i % 4 == 0)