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From: "tiejun.chen" <tiejun.chen@windriver.com>
To: WANG YiFei <yifei_wang@hotmail.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: ppc405 + MCP23S17
Date: Wed, 13 Oct 2010 11:09:05 +0800	[thread overview]
Message-ID: <4CB522D1.5090802@windriver.com> (raw)
In-Reply-To: <BAY158-ds7DB18D88ED851794F4E19F5540@phx.gbl>

WANG YiFei wrote:
> Hi,
> 
>  
> 
> I'm a newbie for linux device driver development.
> 
> We have a custom ppc405 board which has MCP23S17
> 
> (16-Bit I/O Expander with SPI Interface) on it.
> 
> I noticed that current kernel has MCP23S08 driver
> 
> support, I'd like to know:
> 
> 1. if passing platform data to MCP23S08 driver, can it make
> 
>    MCP23S17 work?
> 

These chips should be same vendor product so I think 16-bit mcp23s17 may be
compatible to 8-bit modes. But you have to check the data sheet to confirm this
and track how to configure that as 8-bit mode. After that it's possible to run
mcp23s17 with mcp23s08.c.

> 2. Generally, I'd like to know how to pass platform data to
> 
>    a particular device driver. In my mind, platform data should
> 
>    not be in driver code, right? However, I don't know where is

Firstly you should define this on your dts. Then parse that to register
corresponding of_platform_device or platform_device when you setup your target
on <your target>.c.

When spi_register_driver prober successfully, you can get the platform_data from
associated spi device.

> 
>    the suitable place to pass platform data to driver.
> 
> 3. How to describe this in dts file?
> 

You can get more from the file, Documentation/powerpc/dts-bindings/spi-bus.txt.
Or refer to those existed spi nodes on other platform dts.

Tiejun

>  
> 
> Thanks in advance,
> 
> YiFei
> 
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev

  reply	other threads:[~2010-10-13  3:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-12 14:49 ppc405 + MCP23S17 WANG YiFei
2010-10-13  3:09 ` tiejun.chen [this message]
2010-10-13  6:23   ` WANG YiFei
2010-10-13  7:49     ` tiejun.chen
2010-10-13 15:03       ` WANG YiFei
2010-10-14  5:03         ` tiejun.chen
2010-10-16 10:35     ` Help about chip select on SPI slave devices WANG YiFei
2010-10-18  8:17       ` tiejun.chen

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