Hi Igor, The patch you attached is okay for me. But I suggest to explain this issue more clearly. Actually it is not a no clear reason. i.MX6 platform SPI driver set MOSI and MISO in high level. You can refer to my patch log. Best Regards Haibo Chen > -----Original Message----- > From: Igor Grinberg [mailto:grinberg@xxxxxxxxxxxxxx] > Sent: Tuesday, July 21, 2015 7:53 PM > To: Chen Haibo-B51421; dmitry.torokhov@xxxxxxxxx > Cc: jg1.han@xxxxxxxxxxx; pramod.gurav@xxxxxxxxxxxxxxx; linux- > input@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] Input: ads7846 - correct the value get from SPI > > Hi, > > On 05/22/15 10:02, Haibo Chen wrote: > > According to the touch controller SPEC, SPI return a 16 bit value, > > only 12 bits are valid, they are bit[14-3]. > > > > The value of MISO and MOSI can be configed when SPI in idle mode. > > Currently this touch driver consider the SPI bus set the MOSI and MISO > > in low level when SPI bus in idle mode. So the bit[15] of the value > > get from SPI bus is always 0. But when SPI bus congfig the MOSI and > > MISO in high level when SPI in idle mode, the bit[15] of the value get > > from SPI is always 1, if not mask this bit[15], we may get the wrong > > value. > > > > This patch mask the invalid bit, and make sure to return the correct > > value nomatter how SPI bus configed. > > > > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxxxxxxxx> > > --- > > drivers/input/touchscreen/ads7846.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/input/touchscreen/ads7846.c > > b/drivers/input/touchscreen/ads7846.c > > index e4eb8a6..91b335f 100644 > > --- a/drivers/input/touchscreen/ads7846.c > > +++ b/drivers/input/touchscreen/ads7846.c > > @@ -678,7 +678,7 @@ static int ads7846_get_value(struct ads7846 *ts, > struct spi_message *m) > > * adjust: on-wire is a must-ignore bit, a BE12 value, then > > * padding; built from two 8 bit values written msb-first. > > */ > > - return be16_to_cpup((__be16 *)t->rx_buf) >> 3; > > + return (be16_to_cpup((__be16 *)t->rx_buf) & 0x7ff8) >> 3; > > IIRC, 7845 is the same in regard to SPI bus, so may be we should also > adjust the value in if statement, not just the else part. > > We have the attached patch locally, so may you would like to consider it > or a mixture of both... > > > -- > Regards, > Igor. -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
