[PATCH v1] iio: adc: pac1921: add ACPI support for pac1921

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From: Victor Duicu <victor.duicu@xxxxxxxxxxxxx>

This patch implements ACPI support for pac1921.
Driver can read shunt resistor value and device name from ACPI table.

Signed-off-by: Victor Duicu <victor.duicu@xxxxxxxxxxxxx>
---
 drivers/iio/adc/pac1921.c | 116 +++++++++++++++++++++++++++++++-------
 1 file changed, 97 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/adc/pac1921.c b/drivers/iio/adc/pac1921.c
index 4c2a1c07bc39..9bb61b88aaef 100644
--- a/drivers/iio/adc/pac1921.c
+++ b/drivers/iio/adc/pac1921.c
@@ -67,6 +67,10 @@ enum pac1921_mxsl {
 #define PAC1921_DEFAULT_DI_GAIN		0 /* 2^(value): 1x gain (HW default) */
 #define PAC1921_DEFAULT_NUM_SAMPLES	0 /* 2^(value): 1 sample (HW default) */
 
+#define PAC1921_ACPI_GET_UOHMS_VALS             0
+#define PAC1921_ACPI_GET_NAME			1
+#define PAC1921_DSM_UUID                        "f7bb9932-86ee-4516-a236-7a7a742e55cb"
+
 /*
  * Pre-computed scale factors for BUS voltage
  * format: IIO_VAL_INT_PLUS_NANO
@@ -190,6 +194,7 @@ struct pac1921_priv {
 	u8 n_samples;
 	u8 prev_ovf_flags;
 	u8 ovf_enabled_events;
+	char *name;
 
 	bool first_integr_started;
 	bool first_integr_done;
@@ -1151,6 +1156,79 @@ static void pac1921_regulator_disable(void *data)
 	regulator_disable(regulator);
 }
 
+static int pac1921_match_acpi_device(struct i2c_client *client, struct pac1921_priv *priv)
+{
+	const struct acpi_device_id *device_pointer;
+	acpi_handle handle;
+	union acpi_object *rez;
+	guid_t guid;
+	struct device *dev = &client->dev;
+
+	guid_parse(PAC1921_DSM_UUID, &guid);
+	handle = ACPI_HANDLE(&client->dev);
+
+	device_pointer = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!device_pointer)
+		return -EINVAL;
+
+	rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_UOHMS_VALS, NULL);
+	if (!rez)
+		return dev_err_probe(&client->dev, -EINVAL,
+				     "Could not read shunt from ACPI table\n");
+
+	priv->rshunt_uohm = rez->package.elements[0].integer.value;
+	ACPI_FREE(rez);
+
+	if (priv->rshunt_uohm == 0)
+		return dev_err_probe(&client->dev, -EINVAL, "Shunt value is 0.");
+
+	pac1921_calc_current_scales(priv);
+
+	rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1921_ACPI_GET_NAME, NULL);
+	if (!rez) {
+		priv->name = "";
+		return dev_err_probe(&client->dev, -EINVAL,
+				     "Could not read name from ACPI table\n");
+	}
+
+	priv->name = devm_kmemdup(&client->dev, rez->package.elements->string.pointer,
+				  (size_t)rez->package.elements->string.length + 1,
+				  GFP_KERNEL);
+	priv->name[rez->package.elements->string.length] = '\0';
+	ACPI_FREE(rez);
+
+	return 0;
+}
+
+static int pac1921_match_of_device(struct i2c_client *client, struct pac1921_priv *priv)
+{
+	int ret;
+	struct device *dev = &client->dev;
+
+	/* Read shunt resistor value */
+	ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms", &priv->rshunt_uohm);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Cannot read shunt resistor property\n");
+
+	if (priv->rshunt_uohm == 0 || priv->rshunt_uohm > INT_MAX)
+		return dev_err_probe(dev, -EINVAL, "Invalid shunt resistor: %u\n",
+				     priv->rshunt_uohm);
+
+	pac1921_calc_current_scales(priv);
+
+	if (device_property_present(dev, "name")) {
+		ret = device_property_read_string(dev, "name", (const char **)&priv->name);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+					     "Invalid rail-name value\n");
+	} else {
+		priv->name = "pac1921";
+	}
+
+	return 0;
+}
+
 static int pac1921_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
@@ -1172,22 +1250,14 @@ static int pac1921_probe(struct i2c_client *client)
 				     "Cannot initialize register map\n");
 
 	devm_mutex_init(dev, &priv->lock);
+	if (ACPI_HANDLE(&client->dev))
+		ret = pac1921_match_acpi_device(client, priv);
+	else
+		ret = pac1921_match_of_device(client, priv);
 
-	priv->dv_gain = PAC1921_DEFAULT_DV_GAIN;
-	priv->di_gain = PAC1921_DEFAULT_DI_GAIN;
-	priv->n_samples = PAC1921_DEFAULT_NUM_SAMPLES;
-
-	ret = device_property_read_u32(dev, "shunt-resistor-micro-ohms",
-				       &priv->rshunt_uohm);
-	if (ret)
-		return dev_err_probe(dev, ret,
-				     "Cannot read shunt resistor property\n");
-	if (priv->rshunt_uohm == 0 || priv->rshunt_uohm > INT_MAX)
-		return dev_err_probe(dev, -EINVAL,
-				     "Invalid shunt resistor: %u\n",
-				     priv->rshunt_uohm);
-
-	pac1921_calc_current_scales(priv);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "parameter parsing error\n");
 
 	priv->vdd = devm_regulator_get(dev, "vdd");
 	if (IS_ERR(priv->vdd))
@@ -1198,13 +1268,15 @@ static int pac1921_probe(struct i2c_client *client)
 	if (ret)
 		return dev_err_probe(dev, ret, "Cannot enable vdd regulator\n");
 
-	ret = devm_add_action_or_reset(dev, pac1921_regulator_disable,
-				       priv->vdd);
+	ret = devm_add_action_or_reset(dev, pac1921_regulator_disable, priv->vdd);
 	if (ret)
 		return dev_err_probe(dev, ret,
-			"Cannot add action for vdd regulator disposal\n");
+				     "Cannot add action for vdd regulator disposal\n");
 
 	msleep(PAC1921_POWERUP_TIME_MS);
+	priv->dv_gain = PAC1921_DEFAULT_DV_GAIN;
+	priv->di_gain = PAC1921_DEFAULT_DI_GAIN;
+	priv->n_samples = PAC1921_DEFAULT_NUM_SAMPLES;
 
 	ret = pac1921_init(priv);
 	if (ret)
@@ -1212,7 +1284,7 @@ static int pac1921_probe(struct i2c_client *client)
 
 	priv->iio_info = pac1921_iio;
 
-	indio_dev->name = "pac1921";
+	indio_dev->name = priv->name;
 	indio_dev->info = &priv->iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = pac1921_channels;
@@ -1244,11 +1316,17 @@ static const struct of_device_id pac1921_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, pac1921_of_match);
 
+static const struct acpi_device_id pac1921_acpi_match[] = {
+	{ "MCHP1921" },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, pac1921_acpi_match);
 static struct i2c_driver pac1921_driver = {
 	.driver	 = {
 		.name = "pac1921",
 		.pm = pm_sleep_ptr(&pac1921_pm_ops),
 		.of_match_table = pac1921_of_match,
+		.acpi_match_table = pac1921_acpi_match
 	},
 	.probe = pac1921_probe,
 	.id_table = pac1921_id,

base-commit: fec496684388685647652ab4213454fbabdab099
-- 
2.43.0





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