Re: Reading and Writing to Omap register

[Khem Raj <kraj@mvista.com>]

Arnold said the following on 11/16/2006 7:19 PM:
> Hi All,
>
> I been having problems reading/writing to omap
> registers. I'm using the __raw_read and __raw_write.
> It seems that when I use the __raw_readl the values of
> the register that is passed back to when I read the
> register is always 0. I am accessing a 4byte register
> and I want to write a value to it, but whenever I
> check the values using __raw_read_l, the values does
> not change. But it confuses me when I tried to use a
> __raw_readb it changes the value. It also concerns me 
> because the register that I am accesing is a 4byte
> register and not a 1 bytes register. Below is my
> implementation:
> Using __raw_readl:
> u32 l;
>
> l = 0x10;
> __raw_writel(l,MY_REG);
> printk("MY_REG = %x \n", __raw_readl(l,MY_REG));
>   
why are you passing 'l' as first argument here? This function accepts 
only one argument and that should be MY_REG in your case.
> --> This implementation always  prints a 0.
>
> However when I use this implementation:
> l = 0x10;
> __raw_writeb(l,MY_REG);
> printk("MY_REG = %x \n", __raw_readb(l,MY_REG));
> --> This implementation  prints a 0x10.
>   
same here
> Does anyone knows whats wrong? I am using an omap5912
> and kernel2.6.17. 
>
> I hope somebody could tell me whats wrong. Thank you
> very much in advance.
>
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-- 
Khem Raj <kraj@mvista.com>
MontaVista Software Inc.