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* [PATCH v4] iio: sx9310: Support ACPI property
@ 2021-02-17  6:18 Gwendal Grignou
  2021-02-25 19:57 ` Stephen Boyd
  0 siblings, 1 reply; 2+ messages in thread
From: Gwendal Grignou @ 2021-02-17  6:18 UTC (permalink / raw)
  To: jic23, lars, swboyd, campello; +Cc: linux-iio, Gwendal Grignou

Use device_property_read_... to support both device tree and ACPI
bindings.
Given |semtech,combined-sensors| is a variable array, use
device_property_count to get the length of the array first before
reading it to avoid underflow errors.

Add support for variable array per documentation
("iio/proximity/semtech,sx9310.yaml").

Fixes: 5b19ca2c78a0 ("iio: sx9310: Set various settings from DT")

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
---
 Changes since v3:
   Add "Fixes" comment in commit message
   Fix the logic set COMBMODE register: when we know the DT property is
   missing or incorrect, exit as soon as possible.
 Changes since v2:
   Add comment how the default array is used.
   Add comment in commit message to indicate this CL fix an issue with
     existing use of of_property_read_u32_array() when reading a variale
     length array.
 Changes since v1:
   Use device_property_count_u32(...) instead of device_property_read_u32_array(..., NULL, 0)

 drivers/iio/proximity/sx9310.c | 54 +++++++++++++++++++++-------------
 1 file changed, 34 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/proximity/sx9310.c b/drivers/iio/proximity/sx9310.c
index 6a04959df35e5..77d2c9e102842 100644
--- a/drivers/iio/proximity/sx9310.c
+++ b/drivers/iio/proximity/sx9310.c
@@ -20,6 +20,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/pm.h>
+#include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
@@ -1215,36 +1216,49 @@ static int sx9310_init_compensation(struct iio_dev *indio_dev)
 }
 
 static const struct sx9310_reg_default *
-sx9310_get_default_reg(struct sx9310_data *data, int i,
+sx9310_get_default_reg(struct device *dev, int i,
 		       struct sx9310_reg_default *reg_def)
 {
-	int ret;
-	const struct device_node *np = data->client->dev.of_node;
-	u32 combined[SX9310_NUM_CHANNELS] = { 4, 4, 4, 4 };
+	int ret, count;
+	u32 combined[SX9310_NUM_CHANNELS];
 	unsigned long comb_mask = 0;
 	const char *res;
 	u32 start = 0, raw = 0, pos = 0;
 
 	memcpy(reg_def, &sx9310_default_regs[i], sizeof(*reg_def));
-	if (!np)
-		return reg_def;
-
 	switch (reg_def->reg) {
 	case SX9310_REG_PROX_CTRL2:
-		if (of_property_read_bool(np, "semtech,cs0-ground")) {
+		if (device_property_read_bool(dev, "semtech,cs0-ground")) {
 			reg_def->def &= ~SX9310_REG_PROX_CTRL2_SHIELDEN_MASK;
 			reg_def->def |= SX9310_REG_PROX_CTRL2_SHIELDEN_GROUND;
 		}
 
-		reg_def->def &= ~SX9310_REG_PROX_CTRL2_COMBMODE_MASK;
-		of_property_read_u32_array(np, "semtech,combined-sensors",
-					   combined, ARRAY_SIZE(combined));
-		for (i = 0; i < ARRAY_SIZE(combined); i++) {
-			if (combined[i] <= SX9310_NUM_CHANNELS)
-				comb_mask |= BIT(combined[i]);
+		count = device_property_count_u32(dev, "semtech,combined-sensors");
+		if (count > 0 && count <= ARRAY_SIZE(combined)) {
+			ret = device_property_read_u32_array(dev,
+					"semtech,combined-sensors", combined,
+					count);
+		} else {
+			/*
+			 * Either the property does not exist in the DT, the
+			 * number of entries is incorrect.
+			 */
+			break;
+		}
+		if (ret) {
+			/* We could not read the array (invalid DT). */
+			break;
 		}
 
-		comb_mask &= 0xf;
+		for (i = 0; i < count; i++) {
+			if (combined[i] >= SX9310_NUM_CHANNELS) {
+				/* Invalid sensor (invalid DT). */
+				break;
+			}
+			comb_mask |= BIT(combined[i]);
+		}
+
+		reg_def->def &= ~SX9310_REG_PROX_CTRL2_COMBMODE_MASK;
 		if (comb_mask == (BIT(3) | BIT(2) | BIT(1) | BIT(0)))
 			reg_def->def |= SX9310_REG_PROX_CTRL2_COMBMODE_CS0_CS1_CS2_CS3;
 		else if (comb_mask == (BIT(1) | BIT(2)))
@@ -1256,7 +1270,7 @@ sx9310_get_default_reg(struct sx9310_data *data, int i,
 
 		break;
 	case SX9310_REG_PROX_CTRL4:
-		ret = of_property_read_string(np, "semtech,resolution", &res);
+		ret = device_property_read_string(dev, "semtech,resolution", &res);
 		if (ret)
 			break;
 
@@ -1280,7 +1294,7 @@ sx9310_get_default_reg(struct sx9310_data *data, int i,
 
 		break;
 	case SX9310_REG_PROX_CTRL5:
-		ret = of_property_read_u32(np, "semtech,startup-sensor", &start);
+		ret = device_property_read_u32(dev, "semtech,startup-sensor", &start);
 		if (ret) {
 			start = FIELD_GET(SX9310_REG_PROX_CTRL5_STARTUPSENS_MASK,
 					  reg_def->def);
@@ -1290,7 +1304,7 @@ sx9310_get_default_reg(struct sx9310_data *data, int i,
 		reg_def->def |= FIELD_PREP(SX9310_REG_PROX_CTRL5_STARTUPSENS_MASK,
 					   start);
 
-		ret = of_property_read_u32(np, "semtech,proxraw-strength", &raw);
+		ret = device_property_read_u32(dev, "semtech,proxraw-strength", &raw);
 		if (ret) {
 			raw = FIELD_GET(SX9310_REG_PROX_CTRL5_RAWFILT_MASK,
 					reg_def->def);
@@ -1303,7 +1317,7 @@ sx9310_get_default_reg(struct sx9310_data *data, int i,
 					   raw);
 		break;
 	case SX9310_REG_PROX_CTRL7:
-		ret = of_property_read_u32(np, "semtech,avg-pos-strength", &pos);
+		ret = device_property_read_u32(dev, "semtech,avg-pos-strength", &pos);
 		if (ret)
 			break;
 
@@ -1339,7 +1353,7 @@ static int sx9310_init_device(struct iio_dev *indio_dev)
 
 	/* Program some sane defaults. */
 	for (i = 0; i < ARRAY_SIZE(sx9310_default_regs); i++) {
-		initval = sx9310_get_default_reg(data, i, &tmp);
+		initval = sx9310_get_default_reg(&indio_dev->dev, i, &tmp);
 		ret = regmap_write(data->regmap, initval->reg, initval->def);
 		if (ret)
 			return ret;
-- 
2.30.0.478.g8a0d178c01-goog


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2021-02-17  6:18 [PATCH v4] iio: sx9310: Support ACPI property Gwendal Grignou
2021-02-25 19:57 ` Stephen Boyd

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