linux-kernel - [PATCH v3 2/2] iio: humidity: hdc100x: add manufacturer and device ID check

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Date:   Thu, 28 Jul 2022 00:41:33 +0800
From:   Potin Lai <potin.lai.pt@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>
Cc:     Patrick Williams <patrick@...cx.xyz>,
        Potin Lai <potin.lai@...ntatw.com>, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, Potin Lai <potin.lai.pt@...il.com>
Subject: [PATCH v3 2/2] iio: humidity: hdc100x: add manufacturer and device ID check

Add manufacturer and device ID checking during probe, and skip the
checking if chip model not supported.

Supported:
- HDC1000
- HDC1010
- HDC1050
- HDC1080

Not supported:
- HDC1008

Signed-off-by: Potin Lai <potin.lai.pt@...il.com>
---
 drivers/iio/humidity/hdc100x.c | 70 ++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/humidity/hdc100x.c b/drivers/iio/humidity/hdc100x.c
index 0d514818635cb..593a9d3caf229 100644
--- a/drivers/iio/humidity/hdc100x.c
+++ b/drivers/iio/humidity/hdc100x.c
@@ -34,6 +34,23 @@
 #define HDC100X_REG_CONFIG_ACQ_MODE		BIT(12)
 #define HDC100X_REG_CONFIG_HEATER_EN		BIT(13)
 
+#define HDC100X_REG_MFR_ID	0xFE
+#define HDC100X_REG_DEV_ID	0xFF
+
+#define HDC100X_MFR_ID	0x5449
+
+struct hdc100x_chip_data {
+	bool support_mfr_check;
+};
+
+static const struct hdc100x_chip_data hdc100x_chip_data = {
+	.support_mfr_check	= true,
+};
+
+static const struct hdc100x_chip_data hdc1008_chip_data = {
+	.support_mfr_check	= false,
+};
+
 struct hdc100x_data {
 	struct i2c_client *client;
 	struct mutex lock;
@@ -351,6 +368,34 @@ static const struct iio_info hdc100x_info = {
 	.attrs = &hdc100x_attribute_group,
 };
 
+static int hdc100x_read_mfr_id(struct i2c_client *client)
+{
+	return i2c_smbus_read_word_swapped(client, HDC100X_REG_MFR_ID);
+}
+
+static int hdc100x_read_dev_id(struct i2c_client *client)
+{
+	return i2c_smbus_read_word_swapped(client, HDC100X_REG_DEV_ID);
+}
+
+static bool is_valid_hdc100x(struct i2c_client *client)
+{
+	const struct hdc100x_chip_data *data;
+	int mfr_id, dev_id;
+
+	data = device_get_match_data(&client->dev);
+	if (!data->support_mfr_check)
+		return true;
+
+	mfr_id = hdc100x_read_mfr_id(client);
+	dev_id = hdc100x_read_dev_id(client);
+	if (mfr_id == HDC100X_MFR_ID &&
+	   (dev_id == 0x1000 || dev_id == 0x1050))
+		return true;
+
+	return false;
+}
+
 static int hdc100x_probe(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev;
@@ -361,6 +406,9 @@ static int hdc100x_probe(struct i2c_client *client)
 				     I2C_FUNC_SMBUS_BYTE | I2C_FUNC_I2C))
 		return -EOPNOTSUPP;
 
+	if (!is_valid_hdc100x(client))
+		return -EINVAL;
+
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 	if (!indio_dev)
 		return -ENOMEM;
@@ -396,22 +444,22 @@ static int hdc100x_probe(struct i2c_client *client)
 }
 
 static const struct i2c_device_id hdc100x_id[] = {
-	{ "hdc100x", 0 },
-	{ "hdc1000", 0 },
-	{ "hdc1008", 0 },
-	{ "hdc1010", 0 },
-	{ "hdc1050", 0 },
-	{ "hdc1080", 0 },
+	{ "hdc100X", (kernel_ulong_t)&hdc100x_chip_data },
+	{ "hdc1000", (kernel_ulong_t)&hdc100x_chip_data },
+	{ "hdc1008", (kernel_ulong_t)&hdc1008_chip_data },
+	{ "hdc1010", (kernel_ulong_t)&hdc100x_chip_data },
+	{ "hdc1050", (kernel_ulong_t)&hdc100x_chip_data },
+	{ "hdc1080", (kernel_ulong_t)&hdc100x_chip_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, hdc100x_id);
 
 static const struct of_device_id hdc100x_dt_ids[] = {
-	{ .compatible = "ti,hdc1000" },
-	{ .compatible = "ti,hdc1008" },
-	{ .compatible = "ti,hdc1010" },
-	{ .compatible = "ti,hdc1050" },
-	{ .compatible = "ti,hdc1080" },
+	{ .compatible = "ti,hdc1000", .data = &hdc100x_chip_data },
+	{ .compatible = "ti,hdc1008", .data = &hdc1008_chip_data },
+	{ .compatible = "ti,hdc1010", .data = &hdc100x_chip_data },
+	{ .compatible = "ti,hdc1050", .data = &hdc100x_chip_data },
+	{ .compatible = "ti,hdc1080", .data = &hdc100x_chip_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, hdc100x_dt_ids);
-- 
2.31.1