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Subject[PATCH] mfd/ab8500-gpadc: refactor GPADC API, add raw access
Date
From: Karl Komierowski <karl.komierowski@stericsson.com>

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>
---
drivers/mfd/ab8500-gpadc.c | 56 +++++++++++++++++++++++++++++---------
include/linux/mfd/ab8500/gpadc.h | 5 +++-
2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/drivers/mfd/ab8500-gpadc.c b/drivers/mfd/ab8500-gpadc.c
index f16afb2..e985d17 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
diff --git a/include/linux/mfd/ab8500/gpadc.h b/include/linux/mfd/ab8500/gpadc.h
index 46b9540..2529667 100644
--- a/include/linux/mfd/ab8500/gpadc.h
+++ b/include/linux/mfd/ab8500/gpadc.h
@@ -27,6 +27,9 @@
struct ab8500_gpadc;

struct ab8500_gpadc *ab8500_gpadc_get(char *name);
-int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 input);
+int ab8500_gpadc_convert(struct ab8500_gpadc *gpadc, u8 channel);
+int ab8500_gpadc_read_raw(struct ab8500_gpadc *gpadc, u8 channel);
+int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc,
+ u8 channel, int ad_value);

#endif /* _AB8500_GPADC_H */
--
1.7.3.2


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