Dynamically gate adc clock
authorLars-Peter Clausen <lars@metafoo.de>
Sat, 30 Jan 2010 13:12:17 +0000 (13:12 +0000)
committerLars-Peter Clausen <lars@metafoo.de>
Sat, 30 Jan 2010 13:12:17 +0000 (13:12 +0000)
SVN-Revision: 19394

target/linux/xburst/files-2.6.32/drivers/misc/jz4740-adc.c

index 7da3bcc..c60f939 100644 (file)
@@ -21,6 +21,8 @@
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/err.h>
 #include <linux/jz4740-adc.h>
 
 #define JZ_REG_ADC_ENABLE      0x00
@@ -72,6 +74,9 @@ struct jz4740_adc {
 
        int irq;
 
+       struct clk *clk;
+       unsigned int clk_ref;
+
        struct completion bat_completion;
        struct completion adc_completion;
 
@@ -169,6 +174,26 @@ uint32_t val)
        spin_unlock_irqrestore(&adc->lock, flags);
 }
 
+static inline void jz4740_adc_clk_enable(struct jz4740_adc *adc)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&adc->lock, flags);
+       if (adc->clk_ref++ == 0)
+               clk_enable(adc->clk);
+       spin_unlock_irqrestore(&adc->lock, flags);
+}
+
+static inline void jz4740_adc_clk_disable(struct jz4740_adc *adc)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&adc->lock, flags);
+       if (--adc->clk_ref == 0)
+               clk_disable(adc->clk);
+       spin_unlock_irqrestore(&adc->lock, flags);
+}
+
 long jz4740_adc_read_battery_voltage(struct device *dev,
                                                enum jz_adc_battery_scale scale)
 {
@@ -180,6 +205,8 @@ long jz4740_adc_read_battery_voltage(struct device *dev,
        if (!adc)
                return -ENODEV;
 
+       jz4740_adc_clk_enable(adc);
+
        if (scale == JZ_ADC_BATTERY_SCALE_2V5)
                jz4740_adc_set_cfg(adc, JZ_ADC_CFG_BAT_MB, JZ_ADC_CFG_BAT_MB);
        else
@@ -200,6 +227,8 @@ long jz4740_adc_read_battery_voltage(struct device *dev,
 
        val = readw(adc->base + JZ_REG_ADC_BATTERY);
 
+       jz4740_adc_clk_disable(adc);
+
        if (scale == JZ_ADC_BATTERY_SCALE_2V5)
                voltage = (((long long)val) * 2500000LL) >> 12LL;
        else
@@ -217,6 +246,8 @@ static ssize_t jz4740_adc_read_adcin(struct device *dev,
        unsigned long t;
        uint16_t val;
 
+       jz4740_adc_clk_enable(adc);
+
        jz4740_adc_enable_irq(adc, JZ_ADC_IRQ_ADCIN);
        jz4740_adc_enable_adc(adc, JZ_ADC_ENABLE_ADCIN);
 
@@ -231,6 +262,7 @@ static ssize_t jz4740_adc_read_adcin(struct device *dev,
        }
 
        val = readw(adc->base + JZ_REG_ADC_ADCIN);
+       jz4740_adc_clk_disable(adc);
 
        return sprintf(buf, "%d\n", val);
 }
@@ -277,19 +309,28 @@ static int __devinit jz4740_adc_probe(struct platform_device *pdev)
                goto err_release_mem_region;
        }
 
+       adc->clk = clk_get(&pdev->dev, "adc");
+
+       if (IS_ERR(adc->clk)) {
+               ret = PTR_ERR(adc->clk);
+               dev_err(&pdev->dev, "Failed to get clock: %d\n", ret);
+               goto err_iounmap;
+       }
 
        init_completion(&adc->bat_completion);
        init_completion(&adc->adc_completion);
 
        spin_lock_init(&adc->lock);
 
+       adc->clk_ref = 0;
+
        platform_set_drvdata(pdev, adc);
 
        ret = request_irq(adc->irq, jz4740_adc_irq, 0, pdev->name, adc);
 
        if (ret) {
                dev_err(&pdev->dev, "Failed to request irq: %d\n", ret);
-               goto err_iounmap;
+               goto err_clk_put;
        }
 
        ret = device_create_file(&pdev->dev, &dev_attr_adcin);
@@ -305,6 +346,8 @@ static int __devinit jz4740_adc_probe(struct platform_device *pdev)
 
 err_free_irq:
        free_irq(adc->irq, adc);
+err_clk_put:
+       clk_put(adc->clk);
 err_iounmap:
        platform_set_drvdata(pdev, NULL);
        iounmap(adc->base);
@@ -327,6 +370,8 @@ static int __devexit jz4740_adc_remove(struct platform_device *pdev)
        iounmap(adc->base);
        release_mem_region(adc->mem->start, resource_size(adc->mem));
 
+       clk_put(adc->clk);
+
        platform_set_drvdata(pdev, NULL);
 
        kfree(adc);