mfd: Refactor ab8500 GPADC API, add raw access

Refactor the GPADC interface to avoid bugs in calling code:

- ab8500_gpadc_[convert|read_raw|ad_to_voltage] clarifies
  each functions use case, *convert wraps *read_raw, and we
  can access raw ADC values properly.
- Renamed gpadc function arguments from "input" to "channel" to
  clarify use, so we don't get confused again.

Signed-off-by: Kalle Komierowski <kalle.komierowski@stericsson.com>
Reviewed-by: Mattias Wallin <mattias.wallin@stericsson.com>
Reviewed-by: John Beckett <john.beckett@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 43 insertions, 13 deletions

diff --git a/drivers/mfd/ab8500-gpadc.c b/drivers/mfd/ab8500-gpadc.c
index f16afb234ff9..e985d1701a83 100644
--- a/drivers/mfd/ab8500-gpadc.c
+++ b/drivers/mfd/ab8500-gpadc.c
@@ -143,12 +143,15 @@ struct ab8500_gpadc *ab8500_gpadc_get(char *name)
 }
 EXPORT_SYMBOL(ab8500_gpadc_get);
 
-static int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc, u8 input,
+/**
+ * ab8500_gpadc_ad_to_voltage() - Convert a raw ADC value to a voltage
+ */
+int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc, u8 channel,
         int ad_value)
 {
         int res;
 
-        switch (input) {
+        switch (channel) {
         case MAIN_CHARGER_V:
                 /* For some reason we don't have calibrated data */
                 if (!gpadc->cal_data[ADC_INPUT_VMAIN].gain) {
@@ -232,18 +235,46 @@ static int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc, u8 input,
         }
         return res;
 }
+EXPORT_SYMBOL(ab8500_gpadc_ad_to_voltage);
 
 /**
  * ab8500_gpadc_convert() - gpadc conversion
- * @input:      analog input to be converted to digital data
+ * @channel:    analog channel to be converted to digital data
  *
  * This function converts the selected analog i/p to digital
  * data.
  */
-int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
+int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 channel)
+{
+        int ad_value;
+        int voltage;
+
+        ad_value = ab8500_gpadc_read_raw(gpadc, channel);
+        if (ad_value < 0) {
+                dev_err(gpadc->dev, "GPADC raw value failed ch: %d\n", channel);
+                return ad_value;
+        }
+
+        voltage = ab8500_gpadc_ad_to_voltage(gpadc, channel, ad_value);
+
+        if (voltage < 0)
+                dev_err(gpadc->dev, "GPADC to voltage conversion failed ch:"
+                        " %d AD: 0x%x\n", channel, ad_value);
+
+        return voltage;
+}
+EXPORT_SYMBOL(ab8500_gpadc_convert);
+
+/**
+ * ab8500_gpadc_read_raw() - gpadc read
+ * @channel:    analog channel to be read
+ *
+ * This function obtains the raw ADC value, this then needs
+ * to be converted by calling ab8500_gpadc_ad_to_voltage()
+ */
+int ab8500_gpadc_read_raw(struct ab8500_gpadc *gpadc, u8 channel)
 {
         int ret;
-        u16 data = 0;
         int looplimit = 0;
         u8 val, low_data, high_data;
 
@@ -278,9 +309,9 @@ int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
                 goto out;
         }
 
-        /* Select the input source and set average samples to 16 */
+        /* Select the channel source and set average samples to 16 */
         ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
-                AB8500_GPADC_CTRL2_REG, (input | SW_AVG_16));
+                AB8500_GPADC_CTRL2_REG, (channel | SW_AVG_16));
         if (ret < 0) {
                 dev_err(gpadc->dev,
                         "gpadc_conversion: set avg samples failed\n");
@@ -292,7 +323,7 @@ int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
          * charging current sense if it needed, ABB 3.0 needs some special
          * treatment too.
          */
-        switch (input) {
+        switch (channel) {
         case MAIN_CHARGER_C:
         case USB_CHARGER_C:
                 ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
@@ -359,7 +390,6 @@ int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
                 goto out;
         }
 
-        data = (high_data << 8) | low_data;
         /* Disable GPADC */
         ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
                 AB8500_GPADC_CTRL1_REG, DIS_GPADC);
@@ -370,8 +400,8 @@ int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input)
         /* Disable VTVout LDO this is required for GPADC */
         regulator_disable(gpadc->regu);
         mutex_unlock(&gpadc->ab8500_gpadc_lock);
-        ret = ab8500_gpadc_ad_to_voltage(gpadc, input, data);
-        return ret;
+
+        return (high_data << 8) | low_data;
 
 out:
         /*
@@ -385,10 +415,10 @@ out:
         regulator_disable(gpadc->regu);
         mutex_unlock(&gpadc->ab8500_gpadc_lock);
         dev_err(gpadc->dev,
-                "gpadc_conversion: Failed to AD convert channel %d\n", input);
+                "gpadc_conversion: Failed to AD convert channel %d\n", channel);
         return ret;
 }
-EXPORT_SYMBOL(ab8500_gpadc_convert);
+EXPORT_SYMBOL(ab8500_gpadc_read_raw);
 
 /**
  * ab8500_bm_gpswadcconvend_handler() - isr for s/w gpadc conversion completion