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rk27xx: Turn off lsadc clock when not in use

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Change-Id: Ic3f29e75aa5b894f17e289263a370fac13e2f1d8
This commit is contained in:
Marcin Bukat 2012-08-27 23:32:23 +02:00
parent ae27c331e1
commit 2b6886d107
1 changed files with 15 additions and 5 deletions
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20
firmware/target/arm/rk27xx/adc-rk27xx.c
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@ -28,6 +28,14 @@
unsigned short adc_read(int channel) unsigned short adc_read(int channel)
{ {
unsigned short result;
/* ungate lsadc clocks */
SCU_CLKCFG &= ~(3<<23);
/* wait a bit for clock to stabilize */
udelay(10);
ADC_CTRL = (1<<4)|(1<<3) | (channel & (NUM_ADC_CHANNELS - 1)); ADC_CTRL = (1<<4)|(1<<3) | (channel & (NUM_ADC_CHANNELS - 1));
/* Wait for conversion ready. /* Wait for conversion ready.
@ -38,16 +46,18 @@ unsigned short adc_read(int channel)
* ~10us should be enough so we wait 20us to be on the safe side * ~10us should be enough so we wait 20us to be on the safe side
*/ */
udelay(20); udelay(20);
/* 10bits result */ /* 10bits result */
return (ADC_DATA & 0x3ff); result = (ADC_DATA & 0x3ff);
/* turn off lsadc clock when not in use */
SCU_CLKCFG |= (3<<23);
return result;
} }
void adc_init(void) void adc_init(void)
{ {
/* ADC clock divider to reach max 1MHz */ /* ADC clock divider to reach max 1MHz */
SCU_DIVCON1 = (SCU_DIVCON1 & ~(0xff<<10)) | (49<<10); SCU_DIVCON1 = (SCU_DIVCON1 & ~(0xff<<10)) | (49<<10);
/* enable clocks for ADC */
SCU_CLKCFG &= ~(3<<23);
} }