Messages in this thread | | | Date | Tue, 19 Jun 2012 11:26:05 +0100 | From | Nick Dyer <> | Subject | Re: [PATCH 14/22 v4] Input: atmel_mxt_ts - don't re-read matrix after applying pdata |
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Yufeng Shen wrote: > On Mon, Jun 18, 2012 at 11:03 AM, Nick Dyer <nick.dyer@itdev.co.uk> wrote: >> Daniel Kurtz wrote: >>> The matrix x/y size in the Info ID Block represents the number of x/y >>> trace lines on the device. There is no need to re-read them after >>> applying pdata config, since pdata only configures the object table >>> etnries. The matrix size read from the ID can only be updated by a >>> firmware update. >> >> This isn't correct. For example, mXT224 can be configured as 16x14, 17x13, >> 18x12, etc. This only takes effect when the chip is reset, which is why it >> is necessary to re-read them after applying the config. > > so look at structure mxt_info > > struct mxt_info { > u8 family_id; > u8 variant_id; > u8 version; > u8 build; > u8 matrix_xsize; > u8 matrix_ysize; > u8 object_num; > }; > > I think it is meant to be corresponding to Information Block of the > device, of which > the matrix_xsize and matrix_ysize mean "The size of the matrix the > device supports", > which should be fixed for a certain chip.
As I said, it's not fixed, there is a mode setting (T28 byte 2) which alters the matrix size. This is documented in the protocol guide, if you have it.
You can also verify this if you want: change mode setting, backup, reset, and read the information block, you'll see the matrix size changes. I've just checked that myself on an mXT224.
I also asked the guys at Atmel that I work with, and they confirm that this behaviour is as designed.
> The configurable matrix size is in T9 XSIZE/YSIZE, which, if ever > needed to be read back, > probably read back into something other than mxt_info struct.
The position of the touchscreen within the matrix is a separate configurable setting, you're confusing the two.
cheers
-- Nick Dyer Software Engineer, ITDev Ltd Hardware and Software Development Consultancy Website: http://www.itdev.co.uk
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