linux-kernel - RE: [PATCH v2 01/22] HID: THC: Add documentation

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Message-ID: <IA1PR11MB6098EC67DEAA5336F4F47B19F4242@IA1PR11MB6098.namprd11.prod.outlook.com>
Date: Fri, 15 Nov 2024 05:10:55 +0000
From: "Xu, Even" <even.xu@...el.com>
To: Bagas Sanjaya <bagasdotme@...il.com>, "jikos@...nel.org"
	<jikos@...nel.org>, "bentiss@...nel.org" <bentiss@...nel.org>,
	"corbet@....net" <corbet@....net>, "Aaron, Ma" <aaron.ma@...onical.com>
CC: "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>, "Sun, Xinpeng"
	<xinpeng.sun@...el.com>, Srinivas Pandruvada
	<srinivas.pandruvada@...ux.intel.com>
Subject: RE: [PATCH v2 01/22] HID: THC: Add documentation



> -----Original Message-----
> From: Bagas Sanjaya <bagasdotme@...il.com>
> Sent: Friday, November 15, 2024 12:04 PM
> To: Xu, Even <even.xu@...el.com>; jikos@...nel.org; bentiss@...nel.org;
> corbet@....net; Aaron, Ma <aaron.ma@...onical.com>
> Cc: linux-input@...r.kernel.org; linux-kernel@...r.kernel.org; linux-
> doc@...r.kernel.org; Sun, Xinpeng <xinpeng.sun@...el.com>; Srinivas
> Pandruvada <srinivas.pandruvada@...ux.intel.com>
> Subject: Re: [PATCH v2 01/22] HID: THC: Add documentation
> 
> On Thu, Nov 14, 2024 at 01:33:55PM +0800, Even Xu wrote:
> > +Touch Host Controller is the name of the IP block in PCH that interface with
> Touch Devices (ex:
> > +touchscreen, touchpad etc.). It is comprised of 3 key functional blocks:
> > +- A natively half-duplex Quad I/O capable SPI master
> > +- Low latency I2C interface to support HIDI2C compliant devices
> > +- A HW sequencer with RW DMA capability to system memory
> 
> I see in my htmldocs output that the list above is long running paragraph instead.

You are right, let me fix it in next version.

> 
> > +When THC is configured to SPI mode, opcodes are used for determining the
> read/write IO mode.
> > +There are some OPCode examples for SPI IO mode::
> > +
> > + +--------+---------------------------------+
> > + | opcode |  Corresponding SPI command      |
> > + +========+=================================+
> > + |  0x0B  | Read Single I/O                 |
> > + +--------+---------------------------------+
> > + |  0x02  | Write Single I/O                |
> > + +--------+---------------------------------+
> > + |  0xBB  | Read Dual I/O                   |
> > + +--------+---------------------------------+
> > + |  0xB2  | Write Dual I/O                  |
> > + +--------+---------------------------------+
> > + |  0xEB  | Read Quad I/O                   |
> > + +--------+---------------------------------+
> > + |  0xE2  | Write Quad I/O                  |
> > + +--------+---------------------------------+
> > +
> > <snipped>...
> > +When THC is working in I2C mode, opcodes are used to tell THC what's the
> next PIO type:
> > +I2C SubIP APB register read, I2C SubIP APB register write, I2C touch
> > +IC device read, I2C touch IC device write, I2C touch IC device write followed
> by read.
> > +
> > +Here are the THC pre-defined opcodes for I2C mode::
> > +
> > + +--------+-------------------------------------------+----------+
> > + | opcode |       Corresponding I2C command           | Address  |
> > +
> +========+===========================================+==========+
> > + |  0x12  | Read I2C SubIP APB internal registers     | 0h - FFh |
> > + +--------+-------------------------------------------+----------+
> > + |  0x13  | Write I2C SubIP APB internal registers    | 0h - FFh |
> > + +--------+-------------------------------------------+----------+
> > + |  0x14  | Read external Touch IC through I2C bus    | N/A      |
> > + +--------+-------------------------------------------+----------+
> > + |  0x18  | Write external Touch IC through I2C bus   | N/A      |
> > + +--------+-------------------------------------------+----------+
> > + |  0x1C  | Write then read external Touch IC through | N/A      |
> > + |        | I2C bus                                   |          |
> > + +--------+-------------------------------------------+----------+
> > +
> > <snipped>...
> > +Intel THC uses PRD entry descriptor for every PRD entry. Every PRD
> > +entry descriptor occupies
> > +128 bits memories::
> > +
> > + +-------------------+---------+------------------------------------------------+
> > + | struct field      | bit(s)  | description                                    |
> > +
> +===================+=========+==================================
> ===
> > + +===========+
> > + | dest_addr         | 53..0   | destination memory address, as every entry     |
> > + |                   |         | is 4KB, ignore lowest 10 bits of address.      |
> > + +-------------------+---------+------------------------------------------------+
> > + | reserved1         | 54..62  | reserved                                       |
> > + +-------------------+---------+------------------------------------------------+
> > + | int_on_completion | 63      | completion interrupt enable bit, if this bit   |
> > + |                   |         | set it means THC will trigger a completion     |
> > + |                   |         | interrupt. This bit is set by SW driver.       |
> > + +-------------------+---------+------------------------------------------------+
> > + | len               | 87..64  | how many bytes of data in this entry.          |
> > + +-------------------+---------+------------------------------------------------+
> > + | end_of_prd        | 88      | end of PRD table bit, if this bit is set,      |
> > + |                   |         | it means this entry is last entry in this PRD  |
> > + |                   |         | table. This bit is set by SW driver.           |
> > + +-------------------+---------+------------------------------------------------+
> > + | hw_status         | 90..89  | HW status bits                                 |
> > + +-------------------+---------+------------------------------------------------+
> > + | reserved2         | 127..91 | reserved                                       |
> > + +-------------------+---------+------------------------------------------------+
> 
> Shouldn't these tables be formatted as tables?

Good idea!
Let's format them.

> 
> Thanks.

Thanks for your suggestion!

Best Regards,
Even Xu

> 
> --
> An old man doll... just what I always wanted! - Clara