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* [bug report] spi: imx: add lpspi bus driver
@ 2016-11-23 22:57 Dan Carpenter
  2016-11-24  1:36 ` Pandy Gao
  0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2016-11-23 22:57 UTC (permalink / raw)
  To: pandy.gao-3arQi8VN3Tc; +Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA

Hello Gao Pan,

The patch 5314987de5e5: "spi: imx: add lpspi bus driver" from Nov 22,
2016, leads to the following static checker warning:

	drivers/spi/spi-fsl-lpspi.c:220 fsl_lpspi_set_cmd()
	warn: potential shift truncation.  '0x11 << 30'

drivers/spi/spi-fsl-lpspi.c
   213  static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi,
   214                                bool is_first_xfer)
   215  {
   216          u32 temp = 0;
   217  
   218          temp |= fsl_lpspi->config.bpw - 1;
   219          temp |= fsl_lpspi->config.prescale << 27;
   220          temp |= (fsl_lpspi->config.mode & 0x11) << 30;

Are you sure you didn't intend to write:

		temp |= (fsl_lpspi->config.mode & 0x3) << 30;

The current code doesn't make sense at any rate.

   221          temp |= (fsl_lpspi->config.chip_select & 0x3) << 24;
   222  
   223          /*
   224           * Set TCR_CONT will keep SS asserted after current transfer.
   225           * For the first transfer, clear TCR_CONTC to assert SS.
   226           * For subsequent transfer, set TCR_CONTC to keep SS asserted.
   227           */
   228          temp |= TCR_CONT;
   229          if (is_first_xfer)
   230                  temp &= ~TCR_CONTC;
   231          else
   232                  temp |= TCR_CONTC;
   233  
   234          writel(temp, fsl_lpspi->base + IMX7ULP_TCR);
   235  
   236          dev_dbg(fsl_lpspi->dev, "TCR=0x%x\n", temp);
   237  }

regards,
dan carpenter
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^ permalink raw reply	[flat|nested] 2+ messages in thread

* RE: [bug report] spi: imx: add lpspi bus driver
  2016-11-23 22:57 [bug report] spi: imx: add lpspi bus driver Dan Carpenter
@ 2016-11-24  1:36 ` Pandy Gao
  0 siblings, 0 replies; 2+ messages in thread
From: Pandy Gao @ 2016-11-24  1:36 UTC (permalink / raw)
  To: Dan Carpenter; +Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA

From: Dan Carpenter <mailto:dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>  Sent: Thursday, November 24, 2016 6:57 AM
> To: Pandy Gao <pandy.gao-3arQi8VN3Tc@public.gmane.org>
> Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Subject: [bug report] spi: imx: add lpspi bus driver
> 
> Hello Gao Pan,
> 
> The patch 5314987de5e5: "spi: imx: add lpspi bus driver" from Nov 22,
> 2016, leads to the following static checker warning:
> 
> 	drivers/spi/spi-fsl-lpspi.c:220 fsl_lpspi_set_cmd()
> 	warn: potential shift truncation.  '0x11 << 30'
> 
> drivers/spi/spi-fsl-lpspi.c
>    213  static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi,
>    214                                bool is_first_xfer)
>    215  {
>    216          u32 temp = 0;
>    217
>    218          temp |= fsl_lpspi->config.bpw - 1;
>    219          temp |= fsl_lpspi->config.prescale << 27;
>    220          temp |= (fsl_lpspi->config.mode & 0x11) << 30;
> 
> Are you sure you didn't intend to write:
> 
> 		temp |= (fsl_lpspi->config.mode & 0x3) << 30;
> 
> The current code doesn't make sense at any rate.

Yes, you are right. Will submit a patch to fix this bug. Thanks!

Best  Regards
Gao Pan

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