iio: adc: cc10001: Fix incorrect use of power-up/power-down register

At present we are incorrectly setting the register to 0x1 to power up
the ADC. Since it is an active high power down register, we need to set
the register to 0x0 to actually power up. Conversely, writing 0x1 to the
register powers it down.

This commit adds a couple of helpers to make the code clearer and then
use them to do the power-up/power-down properly.

Fixes: 1664f6a5b0c8 ("iio: adc: Cosmic Circuits 10001 ADC driver")
Signed-off-by: Naidu Tellapati <naidu.tellapati@imgtec.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 19 insertions, 14 deletions

diff --git a/drivers/iio/adc/cc10001_adc.c b/drivers/iio/adc/cc10001_adc.c
index 357e6c213784..e7810ac8e295 100644
--- a/drivers/iio/adc/cc10001_adc.c
+++ b/drivers/iio/adc/cc10001_adc.c
@@ -35,8 +35,9 @@
 #define CC10001_ADC_EOC_SET             BIT(0)
 
 #define CC10001_ADC_CHSEL_SAMPLED       0x0c
-#define CC10001_ADC_POWER_UP            0x10
-#define CC10001_ADC_POWER_UP_SET        BIT(0)
+#define CC10001_ADC_POWER_DOWN          0x10
+#define CC10001_ADC_POWER_DOWN_SET      BIT(0)
+
 #define CC10001_ADC_DEBUG               0x14
 #define CC10001_ADC_DATA_COUNT          0x20
 
@@ -78,6 +79,18 @@ static inline u32 cc10001_adc_read_reg(struct cc10001_adc_device *adc_dev,
         return readl(adc_dev->reg_base + reg);
 }
 
+static void cc10001_adc_power_up(struct cc10001_adc_device *adc_dev)
+{
+        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN, 0);
+        ndelay(adc_dev->start_delay_ns);
+}
+
+static void cc10001_adc_power_down(struct cc10001_adc_device *adc_dev)
+{
+        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN,
+                              CC10001_ADC_POWER_DOWN_SET);
+}
+
 static void cc10001_adc_start(struct cc10001_adc_device *adc_dev,
                               unsigned int channel)
 {
@@ -139,11 +152,7 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p)
 
         mutex_lock(&adc_dev->lock);
 
-        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
-                              CC10001_ADC_POWER_UP_SET);
-
-        /* Wait for 8 (6+2) clock cycles before activating START */
-        ndelay(adc_dev->start_delay_ns);
+        cc10001_adc_power_up(adc_dev);
 
         /* Calculate delay step for eoc and sampled data */
         delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
@@ -167,7 +176,7 @@ static irqreturn_t cc10001_adc_trigger_h(int irq, void *p)
         }
 
 done:
-        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
+        cc10001_adc_power_down(adc_dev);
 
         mutex_unlock(&adc_dev->lock);
 
@@ -186,11 +195,7 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev,
         unsigned int delay_ns;
         u16 val;
 
-        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
-                              CC10001_ADC_POWER_UP_SET);
-
-        /* Wait for 8 (6+2) clock cycles before activating START */
-        ndelay(adc_dev->start_delay_ns);
+        cc10001_adc_power_up(adc_dev);
 
         /* Calculate delay step for eoc and sampled data */
         delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
@@ -199,7 +204,7 @@ static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev,
 
         val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns);
 
-        cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
+        cc10001_adc_power_down(adc_dev);
 
         return val;
 }