[PATCH v6 2/5] iio: temperature: tmp117: improve fallback capabilities

Marco Felsch
2023-02-28T09:05:36Z

Don't error if the device-id found don't match the device-id for the
TMP117 sensor since other TMPxxx might be compatible to the TMP117. The
fallback mechanism tries to gather the required information from the
of_device_id or from the i2c_client information.

The commit also prepares the driver for adding new devices more easily
by making use of switch-case at the relevant parts.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
v6:
- no changes
v5:
- identify: make use of v6.2 available i2c_client_get_device_id()
- identify: adapt dev_err() message
- probe: keep ret variable
v4:
- new patch to implement possible fallback (Jonathan)

drivers/iio/temperature/tmp117.c | 44 ++++++++++++++++++++++++--------
1 file changed, 34 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/temperature/tmp117.c b/drivers/iio/temperature/tmp117.c
index f9b8f2b570f6b..8a3992d9ee937 100644
--- a/drivers/iio/temperature/tmp117.c
+++ b/drivers/iio/temperature/tmp117.c
@@ -16,6 +16,7 @@
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/limits.h>
+#include <linux/property.h>

#include <linux/iio/iio.h>

@@ -115,23 +116,40 @@ static const struct iio_info tmp117_info = {

static int tmp117_identify(struct i2c_client *client)
{
+ const struct i2c_device_id *id;
+ unsigned long match_data;
int dev_id;

dev_id = i2c_smbus_read_word_swapped(client, TMP117_REG_DEVICE_ID);
if (dev_id < 0)
return dev_id;
- if (dev_id != TMP117_DEVICE_ID) {
- dev_err(&client->dev, "TMP117 not found\n");
- return -ENODEV;
+
+ switch (dev_id) {
+ case TMP117_DEVICE_ID:
+ return dev_id;
}
- return 0;
+
+ dev_info(&client->dev, "Unknown device id (0x%x), use fallback compatible\n",
+ dev_id);
+
+ match_data = (uintptr_t)device_get_match_data(&client->dev);
+ if (match_data)
+ return match_data;
+
+ id = i2c_client_get_device_id(client);
+ if (id)
+ return id->driver_data;
+
+ dev_err(&client->dev, "Failed to identify unsupported device\n");
+
+ return -ENODEV;
}

static int tmp117_probe(struct i2c_client *client)
{
struct tmp117_data *data;
struct iio_dev *indio_dev;
- int ret;
+ int ret, dev_id;

if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -EOPNOTSUPP;
@@ -140,6 +158,8 @@ static int tmp117_probe(struct i2c_client *client)
if (ret < 0)
return ret;

+ dev_id = ret;
+
indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
if (!indio_dev)
return -ENOMEM;
@@ -148,24 +168,28 @@ static int tmp117_probe(struct i2c_client *client)
data->client = client;
data->calibbias = 0;

- indio_dev->name = "tmp117";
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &tmp117_info;

- indio_dev->channels = tmp117_channels;
- indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
+ switch (dev_id) {
+ case TMP117_DEVICE_ID:
+ indio_dev->channels = tmp117_channels;
+ indio_dev->num_channels = ARRAY_SIZE(tmp117_channels);
+ indio_dev->name = "tmp117";
+ break;
+ }

return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct of_device_id tmp117_of_match[] = {
- { .compatible = "ti,tmp117", },
+ { .compatible = "ti,tmp117", .data = (void *)TMP117_DEVICE_ID },
{ }
};
MODULE_DEVICE_TABLE(of, tmp117_of_match);

static const struct i2c_device_id tmp117_id[] = {
- { "tmp117", 0 },
+ { "tmp117", TMP117_DEVICE_ID },
{ }
};
MODULE_DEVICE_TABLE(i2c, tmp117_id);
--
2.30.2