> -----Original Message----- > From: Wolfram Sang [mailto:wsa@xxxxxxxxxxxxx] > Sent: Friday, October 03, 2014 3:55 PM > To: Yuan Yao-B46683 > Cc: marex@xxxxxxx; LW@xxxxxxxxxxxxxxxxxxx; mark.rutland@xxxxxxx; Duan > Fugang-B38611; shawn.guo@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx > Subject: Re: [PATCH v8 1/2] i2c: imx: add DMA support for freescale i2c > driver > > -#include <linux/init.h> > > -#include <linux/kernel.h> > > -#include <linux/module.h> > > +#include <linux/clk.h> > > +#include <linux/completion.h> > > +#include <linux/delay.h> > > +#include <linux/dma-mapping.h> > > +#include <linux/dmaengine.h> > > +#include <linux/dmapool.h> > > #include <linux/errno.h> > > #include <linux/err.h> > > #include <linux/interrupt.h> > > -#include <linux/delay.h> > > #include <linux/i2c.h> > > +#include <linux/init.h> > > #include <linux/io.h> > > -#include <linux/sched.h> > > -#include <linux/platform_device.h> > > -#include <linux/clk.h> > > -#include <linux/slab.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > #include <linux/of.h> > > #include <linux/of_device.h> > > +#include <linux/of_dma.h> > > #include <linux/platform_data/i2c-imx.h> > > +#include <linux/platform_device.h> > > +#include <linux/sched.h> > > +#include <linux/slab.h> > > This is a seperate patch. [Yuan Yao] Here I just adjust the order of the include file as alphabetical order. If it looks strange I can only add the include files about DMA. > > > > + while (1) { > > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); > > + if (temp & I2SR_ICF) > > + break; > > + if (time_after(jiffies, orig_jiffies + > > + msecs_to_jiffies(IMX_I2C_DMA_TIMEOUT))) { > > + dev_dbg(dev, "<%s> Timeout\n", __func__); > > + return -ETIMEDOUT; > > + } > > + schedule(); > > That might have been asked before. Is there no interrupt for this? > [Yuan Yao] No, there is no interrupt. After DMA callback, I must wait until the last byte transfer completely. It's a very short time which less than 10us. By the way, how about use udelay(10) instead of schedule()? udelay(10) is waiting a appropriate time. schedule() is waiting too long for i2c but may be good for whole system. Can you give me some suggestion? Thanks for your review. Best Regards, Yuan Yao -- 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
