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[v7,3/5] adc: meson-saradc: add support for getting reference voltage value

Message ID 20210218103318.18915-4-m.szyprowski@samsung.com
State Accepted
Commit 97ab802aa36f1ee74196525af0e844656ae3dc63
Headers show
Series VIM3: add support for checking 'Function' button state | expand

Commit Message

Marek Szyprowski Feb. 18, 2021, 10:33 a.m. UTC 
Add support for getting the 'vref-supply' regulator and register it as
ADC's reference voltage regulator, so clients can translate sampled ADC
values to the voltage.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

Reviewed-by: Simon Glass <sjg@chromium.org>

---
 drivers/adc/meson-saradc.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

-- 
2.17.1
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Patch

diff --git a/drivers/adc/meson-saradc.c b/drivers/adc/meson-saradc.c
index 21db55831d..1a45a3a265 100644
--- a/drivers/adc/meson-saradc.c
+++ b/drivers/adc/meson-saradc.c
@@ -18,6 +18,7 @@ 
 #include <linux/delay.h>
 #include <linux/math64.h>
 #include <linux/bitfield.h>
+#include <power/regulator.h>
 
 #define MESON_SAR_ADC_REG0					0x00
 	#define MESON_SAR_ADC_REG0_PANEL_DETECT			BIT(31)
@@ -656,7 +657,10 @@  static int meson_saradc_stop(struct udevice *dev)
 
 static int meson_saradc_probe(struct udevice *dev)
 {
+	struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
 	struct meson_saradc_priv *priv = dev_get_priv(dev);
+	struct udevice *vref;
+	int vref_uv;
 	int ret;
 
 	ret = regmap_init_mem(dev_ofnode(dev), &priv->regmap);
@@ -675,6 +679,23 @@  static int meson_saradc_probe(struct udevice *dev)
 
 	priv->active_channel = -1;
 
+	ret = device_get_supply_regulator(dev, "vref-supply", &vref);
+	if (ret) {
+		printf("can't get vref-supply: %d\n", ret);
+		return ret;
+	}
+
+	vref_uv = regulator_get_value(vref);
+	if (vref_uv < 0) {
+		printf("can't get vref-supply value: %d\n", vref_uv);
+		return vref_uv;
+	}
+
+	/* VDD supplied by common vref pin */
+	uc_pdata->vdd_supply = vref;
+	uc_pdata->vdd_microvolts = vref_uv;
+	uc_pdata->vss_microvolts = 0;
+
 	return 0;
 }