[PATCH v3 1/3] input: sun4i-a10-lradc-keys: Add support for A83T

[Ziping Chen <techping.chan@gmail.com>]

From: Ziping Chen <techping.chan@gmail.com>

Allwinner A83T SoC has a low res adc like the one
in Allwinner A10 SoC, however, the A10 SoC's vref
of lradc internally is divided by 2/3 and the A83T
SoC's vref of lradc internally is divided by 3/4,
thus add a hardware variant for it to be compatible
with various devices.

Signed-off-by: Ziping Chen <techping.chan@gmail.com>
---
 drivers/input/keyboard/sun4i-lradc-keys.c | 38 +++++++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
index a37c172452e6..bfd2038a9047 100644
--- a/drivers/input/keyboard/sun4i-lradc-keys.c
+++ b/drivers/input/keyboard/sun4i-lradc-keys.c
@@ -46,6 +46,7 @@
 #define CONTINUE_TIME_SEL(x)	((x) << 16) /* 4 bits */
 #define KEY_MODE_SEL(x)		((x) << 12) /* 2 bits */
 #define LEVELA_B_CNT(x)		((x) << 8)  /* 4 bits */
+#define HOLD_KEY_EN(x)		((x) << 7)
 #define HOLD_EN(x)		((x) << 6)
 #define LEVELB_VOL(x)		((x) << 4)  /* 2 bits */
 #define SAMPLE_RATE(x)		((x) << 2)  /* 2 bits */
@@ -63,6 +64,25 @@
 #define	CHAN0_KEYDOWN_IRQ	BIT(1)
 #define CHAN0_DATA_IRQ		BIT(0)
 
+/* struct lradc_variant - Describe sun4i-a10-lradc-keys hardware variant
+ * @divisor_numerator:		The numerator of lradc Vref internally divisor
+ * @divisor_denominator:	The denominator of lradc Vref internally divisor
+ */
+struct lradc_variant {
+	u8 divisor_numerator;
+	u8 divisor_denominator;
+};
+
+static const struct lradc_variant lradc_variant_a10 = {
+	.divisor_numerator = 2,
+	.divisor_denominator = 3
+};
+
+static const struct lradc_variant r_lradc_variant_a83t = {
+	.divisor_numerator = 3,
+	.divisor_denominator = 4
+};
+
 struct sun4i_lradc_keymap {
 	u32 voltage;
 	u32 keycode;
@@ -74,6 +94,7 @@ struct sun4i_lradc_data {
 	void __iomem *base;
 	struct regulator *vref_supply;
 	struct sun4i_lradc_keymap *chan0_map;
+	const struct lradc_variant *variant;
 	u32 chan0_map_count;
 	u32 chan0_keycode;
 	u32 vref;
@@ -128,9 +149,9 @@ static int sun4i_lradc_open(struct input_dev *dev)
 	if (error)
 		return error;
 
-	/* lradc Vref internally is divided by 2/3 */
-	lradc->vref = regulator_get_voltage(lradc->vref_supply) * 2 / 3;
-
+	lradc->vref = regulator_get_voltage(lradc->vref_supply) *
+		      lradc->variant->divisor_numerator /
+		      lradc->variant->divisor_denominator;
 	/*
 	 * Set sample time to 4 ms / 250 Hz. Wait 2 * 4 ms for key to
 	 * stabilize on press, wait (1 + 1) * 4 ms for key release
@@ -222,6 +243,12 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
 	if (error)
 		return error;
 
+	lradc->variant = of_device_get_match_data(&pdev->dev);
+	if (!lradc->variant) {
+		dev_err(&pdev->dev, "Missing sun4i-a10-lradc-keys variant\n");
+		return -EINVAL;
+	}
+
 	lradc->vref_supply = devm_regulator_get(dev, "vref");
 	if (IS_ERR(lradc->vref_supply))
 		return PTR_ERR(lradc->vref_supply);
@@ -265,7 +292,10 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id sun4i_lradc_of_match[] = {
-	{ .compatible = "allwinner,sun4i-a10-lradc-keys", },
+	{ .compatible = "allwinner,sun4i-a10-lradc-keys",
+		.data = &lradc_variant_a10 },
+	{ .compatible = "allwinner,sun8i-a83t-r-lradc-keys",
+		.data = &r_lradc_variant_a83t },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
-- 
2.11.0