iio: st_pressure: Support i2c probe using acpi

Compatible strings are not available on ACPI based systems. This patch adds
support to use DSDT information read from platform BIOS instead for probing
st pressure sensors.
Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/pressure/st_pressure.h

@@ -14,6 +14,14 @@
 #include <linux/types.h>
 #include <linux/iio/common/st_sensors.h>
 
+enum st_press_type {
+	LPS001WP,
+	LPS25H,
+	LPS331AP,
+	LPS22HB,
+	ST_PRESS_MAX,
+};
+
 #define LPS001WP_PRESS_DEV_NAME		"lps001wp"
 #define LPS25H_PRESS_DEV_NAME		"lps25h"
 #define LPS331AP_PRESS_DEV_NAME		"lps331ap"

drivers/iio/pressure/st_pressure_i2c.c

@@ -11,6 +11,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/acpi.h>
 #include <linux/i2c.h>
 #include <linux/iio/iio.h>
 
@@ -43,25 +44,56 @@ MODULE_DEVICE_TABLE(of, st_press_of_match);
 #define st_press_of_match NULL
 #endif
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id st_press_acpi_match[] = {
+	{"SNO9210", LPS22HB},
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, st_press_acpi_match);
+#else
+#define st_press_acpi_match NULL
+#endif
+
+static const struct i2c_device_id st_press_id_table[] = {
+	{ LPS001WP_PRESS_DEV_NAME, LPS001WP },
+	{ LPS25H_PRESS_DEV_NAME,  LPS25H },
+	{ LPS331AP_PRESS_DEV_NAME, LPS331AP },
+	{ LPS22HB_PRESS_DEV_NAME, LPS22HB },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, st_press_id_table);
+
 static int st_press_i2c_probe(struct i2c_client *client,
 						const struct i2c_device_id *id)
 {
 	struct iio_dev *indio_dev;
 	struct st_sensor_data *press_data;
-	int err;
+	int ret;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*press_data));
 	if (!indio_dev)
 		return -ENOMEM;
 
 	press_data = iio_priv(indio_dev);
-	st_sensors_of_i2c_probe(client, st_press_of_match);
+
+	if (client->dev.of_node) {
+		st_sensors_of_i2c_probe(client, st_press_of_match);
+	} else if (ACPI_HANDLE(&client->dev)) {
+		ret = st_sensors_match_acpi_device(&client->dev);
+		if ((ret < 0) || (ret >= ST_PRESS_MAX))
+			return -ENODEV;
+
+		strncpy(client->name, st_press_id_table[ret].name,
+				sizeof(client->name));
+		client->name[sizeof(client->name) - 1] = '\0';
+	} else if (!id)
+		return -ENODEV;
 
 	st_sensors_i2c_configure(indio_dev, client, press_data);
 
-	err = st_press_common_probe(indio_dev);
-	if (err < 0)
-		return err;
+	ret = st_press_common_probe(indio_dev);
+	if (ret < 0)
+		return ret;
 
 	return 0;
 }
@@ -73,18 +105,11 @@ static int st_press_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
-static const struct i2c_device_id st_press_id_table[] = {
-	{ LPS001WP_PRESS_DEV_NAME },
-	{ LPS25H_PRESS_DEV_NAME },
-	{ LPS331AP_PRESS_DEV_NAME },
-	{},
-};
-MODULE_DEVICE_TABLE(i2c, st_press_id_table);
-
 static struct i2c_driver st_press_driver = {
 	.driver = {
 		.name = "st-press-i2c",
 		.of_match_table = of_match_ptr(st_press_of_match),
+		.acpi_match_table = ACPI_PTR(st_press_acpi_match),
 	},
 	.probe = st_press_i2c_probe,
 	.remove = st_press_i2c_remove,