On Fri, Jun 29, 2012 at 04:24:03PM +0800, Marek Vasut wrote: > This patch implements DMA support into mxs-i2c. DMA transfers are now enabled > via DT. The DMA operation is enabled by default. > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > Cc: Detlev Zundel <dzu@xxxxxxx> > CC: Dong Aisheng <b29396@xxxxxxxxxxxxx> > CC: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx> > Cc: Linux ARM kernel <linux-arm-kernel@xxxxxxxxxxxxxxxxxxx> > Cc: linux-i2c@xxxxxxxxxxxxxxx > CC: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > CC: Shawn Guo <shawn.guo@xxxxxxxxxx> > Cc: Stefano Babic <sbabic@xxxxxxx> > CC: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > Cc: Wolfgang Denk <wd@xxxxxxx> > Cc: Wolfram Sang <w.sang@xxxxxxxxxxxxxx> > --- > Documentation/devicetree/bindings/i2c/i2c-mxs.txt | 4 + > arch/arm/boot/dts/imx28.dtsi | 2 + > drivers/i2c/busses/i2c-mxs.c | 267 +++++++++++++++++++-- > 3 files changed, 251 insertions(+), 22 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt > index d2bf750..9497ee0 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-mxs.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-mxs.txt > @@ -5,6 +5,10 @@ Required properties: > - reg: Should contain registers location and length > - interrupts: Should contain ERROR and DMA interrupts > - clock-frequency: desired I2C bus clock frequency in Hz. > +- fsl,i2c-dma-channel: APBX DMA channel for the I2C Shoundn't this be optional? > + /* > + * The last descriptor must have this callback, > + * to finish the DMA transaction. > + */ > + desc->callback = mxs_i2c_dma_irq_callback; > + desc->callback_param = i2c; > + > + /* Start the transfer. */ > + dmaengine_submit(desc); > + dma_async_issue_pending(i2c->dmach); > + return 0; > + > +/* Read failpath. */ > +read_init_dma_fail: > + dma_unmap_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE); > +select_init_dma_fail: > + dma_unmap_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE); > +select_init_pio_fail: > + return 1; look strange why return 1; > + > + One more unnecessary line? > +/* Write failpath. */ > +write_init_dma_fail: > + dma_unmap_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE); > +write_init_pio_fail: > + return 1; > +} > + .. > @@ -291,6 +459,7 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, > > timeout: > dev_dbg(i2c->dev, "Timeout!\n"); > + mxs_i2c_dma_finish(i2c); Shared with pio? > mxs_i2c_reset(i2c); > return -ETIMEDOUT; > } Regards Dong Aisheng -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
