hw->clk=clk_get(&pdev->dev,"spi");
if(IS_ERR(hw->clk)){
dev_err(&pdev->dev,"No clock for devicen");
err=PTR_ERR(hw->clk);
gotoerr_no_clk;
}

/* for the moment, permanently enable the clock */

clk_enable(hw->clk);

/include/asm-arm/plat-s3c24xx/clock.h
/include/asm-arm/arch-s3c2410/regs-clock.h
/arch/arm/mach-s3c2410/clock.c

/* standard clock definitions */

staticstructclk init_clocks_disable[]={
{
.name="nand",
.id=-1,
.parent=&clk_h,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_NAND,
},{
.name="sdi",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_SDI,
},{
.name="adc",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_ADC,
},{
.name="i2c",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_IIC,
},{
.name="iis",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_IIS,
},{
.name="spi",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_SPI,
}
};

staticstructclk init_clocks[]={
{
.name="lcd",
.id=-1,
.parent=&clk_h,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_LCDC,
},{
.name="gpio",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_GPIO,
},{
.name="usb-host",
.id=-1,
.parent=&clk_h,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_USBH,
},{
.name="usb-device",
.id=-1,
.parent=&clk_h,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_USBD,
},{
.name="timers",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_PWMT,
},{
.name="uart",
.id=0,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_UART0,
},{
.name="uart",
.id=1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_UART1,
},{
.name="uart",
.id=2,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_UART2,
},{
.name="rtc",
.id=-1,
.parent=&clk_p,
.enable=s3c2410_clkcon_enable,
.ctrlbit=S3C2410_CLKCON_RTC,
},{
.name="watchdog",
.id=-1,
.parent=&clk_p,
.ctrlbit=0,
},{
.name="usb-bus-host",
.id=-1,
.parent=&clk_usb_bus,
},{
.name="usb-bus-gadget",
.id=-1,
.parent=&clk_usb_bus,
},
};