Re: Fwd: Question about SPI of S3c2410 in 2.6.14.1 KERNEL

[Ben Dooks <ben-linux-arm@xxxxxxxxx>]

On Sun, Aug 27, 2006 at 07:07:57PM +0800, TimFeng wrote:
> Dear all,
> 
> I have some trouble in using SPI of SMDK2410 in 2.6.14 kernel. In such
> kernel, the spi register is mapped to the virsual address use the code
> below,

Upgrade to 2.6.18-rc4, there's a proper SPI core, and an driver for
the s3c2410 spi.
 
> /*file s3c2410.c*/
> Firstly, I add the SPI register to be mapped to virsual address:
> static struct map_desc s3c2410_iodesc[] __initdata = {
> IODESC_ENT(USBHOST),
> IODESC_ENT(CLKPWR),
> IODESC_ENT(LCD),
> IODESC_ENT(TIMER),
> IODESC_ENT(ADC),
> IODESC_ENT(WATCHDOG),
> IODESC_ENT(IIS),
> IODESC_ENT(SPI), /*make SPI to be mapped*/
> };

Nope, this is only for items that are _shared_ between various
places in the kernel!
 
> and add the spi to the device list
> /*File mach-smdk2410.c*/
> 
> static struct platform_device *smdk2410_devices[] __initdata = {
> &s3c_device_usb,
> &s3c_device_lcd,
> &s3c_device_wdt,
> &s3c_device_i2c,
> &s3c_device_iis,
> &s3c_device_spi0,
> // &s3c_device_spi1,
> &s3c_device_nand,
> };
> 
> 
> Secondly, when I access the SPI register using the virsual address
> S3C24XX_VA_SPI   or use probe function as follow:
> static int s3c2410_spi_probe(struct device *dev)
> {
> struct platform_device *pdev = to_platform_device(dev);
> struct resource *res;
> int ret;
>  static struct resource *s3c2410_spi0_mem;
> 
> 
> printk("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev);
> 
> /* get the memory region */
> res  = pdev->resource;
> s3c2410_spi0_mem = request_mem_region(res->start, res->end-res->start+1,
>         pdev->name);
> 
> if (s3c2410_spi0_mem == NULL) {
>  printk( "failed to reserve memory region\n");
>  ret = -1;
>  goto exit_err;
> }
> 
> s3c2410_spi0_base = ioremap(res->start, res->end - res->start + 1);
> if (s3c2410_spi0_base == NULL) {
>  printk("failed ioremap()\n");
>  ret = -1;
>  goto exit_err;
> }
> printk("s3c2410_rtc_base=%p\n", s3c2410_spi0_base);
> printk("PADDR=%x,size=%x\n", s3c2410_spi0_mem->start,
> s3c2410_spi0_mem->end-s3c2410_spi0_mem->start+1);
> printk("rSPCON0-- is %x\n", readl((0x0) + s3c2410_spi0_base));
> printk("rSPSTA0-- is %x\n", readl((0x4) + s3c2410_spi0_base));
> printk("rSPPIN0-- is %x\n", readl((0x8) + s3c2410_spi0_base));
> printk("rSPPRE0-- is %x\n", readl((0xc) + s3c2410_spi0_base));
> 
> 
> return 0;
> 
> exit_err:
> printk("error %d during initialisation\n", ret);
> 
> return ret;
> }
> the printk result is:
> 
> s3c2410_rtc_base=c1910000
> PADDR=59000000,size=20
> rSPCON0-- is 0
> rSPSTA0-- is 1
> rSPPIN0-- is 0
> rSPPRE0-- is 0
> 
> But I found something is very strang,the reset value of rSPPIN0 should be
> 0x00000002 . But now what the value I get is wrong. And when I try to write
> to these
> regester above, but fail, value of such register can not be modify. The 
> same
> situation happen when I directory use the visual address But in the loader
> or when system init I can modify the register.
> The same situation happens when I use the  S3C24XX_VA_SPI   to read/wiret
> the register.

I expect you've forgotten to enable the clock to the relevant spi
unit.

-- 
Ben

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