Bug#1029850: linux: Driver not loaded for ST Microelectronics LSM6DS3TR-C accelerometer (acpi:SMO8B30:SMO8B30:)

[Darrell Kavanagh <darrell.kavanagh@gmail.com>]

I've been in touch with the maintainers of the st_lsm6dsx kernel module and we've made good progress. In short, it is now working. See details below:

On Sun, 29 Jan 2023 at 18:10, Jonathan Cameron <jic23@kernel.org> wrote:

At least this is using the ST PNP ID which is better than average
(long story!)

The driver in question (ultimately drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
does not currently have an ACPI support.  It should be straight forwards
to add though the driver first needs converting to use
device_get_match_data() with appropriate fallback so that it will match on
ACPI, OF or original spi_device_id tables

Completely untested but something like the following
(the offset in the enum is needed to allow us to tell if we got a result when
calling device_get_match_data() as it returns NULL on failure IIRC)

I'm not sure how sucessful the driver will be at finding any interrupts etc, but
it may get you basic functionality.

Good luck and others more familiar with the driver may well tell me what I forgot
when hacking the below ;)

diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
index 499fcf8875b4..2617ce236ddc 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h
@@ -39,7 +39,7 @@
 #define ST_ISM330IS_DEV_NAME   "ism330is"

 enum st_lsm6dsx_hw_id {
-       ST_LSM6DS3_ID,
+       ST_LSM6DS3_ID = 1,
        ST_LSM6DS3H_ID,
        ST_LSM6DSL_ID,
        ST_LSM6DSM_ID,
diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
index df5f60925260..ecfceb2fb3db 100644
--- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
+++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_i2c.c
@@ -23,10 +23,15 @@ static const struct regmap_config st_lsm6dsx_i2c_regmap_config = {

 static int st_lsm6dsx_i2c_probe(struct i2c_client *client)
 {
-       const struct i2c_device_id *id = i2c_client_get_device_id(client);
-       int hw_id = id->driver_data;
+       int hw_id;
        struct regmap *regmap;

+       hw_id = (kernel_ulong_t)device_get_match_data(&client->dev);
+       if (!hw_id)
+               hw_id = i2c_client_get_device_id(client)->driver_data;
+       if (!hw_id)
+               return -EINVAL;
+
        regmap = devm_regmap_init_i2c(client, &st_lsm6dsx_i2c_regmap_config);
        if (IS_ERR(regmap)) {
                dev_err(&client->dev, "Failed to register i2c regmap %ld\n", PTR_ERR(regmap));
@@ -129,6 +134,10 @@ static const struct of_device_id st_lsm6dsx_i2c_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, st_lsm6dsx_i2c_of_match);

+static const struct acpi_device_id st_lsm6dsx_i2c_acpi_match[] = {
+       { "SMO8B30", ST_LSM6DS3TRC_ID, },
+};
+
 static const struct i2c_device_id st_lsm6dsx_i2c_id_table[] = {
        { ST_LSM6DS3_DEV_NAME, ST_LSM6DS3_ID },
        { ST_LSM6DS3H_DEV_NAME, ST_LSM6DS3H_ID },
@@ -161,6 +170,7 @@ static struct i2c_driver st_lsm6dsx_driver = {
                .name = "st_lsm6dsx_i2c",
                .pm = pm_sleep_ptr(&st_lsm6dsx_pm_ops),
                .of_match_table = st_lsm6dsx_i2c_of_match,
+               .acpi_match_table = st_lsm6dsx_i2c_acpi_match,
        },
        .probe_new = st_lsm6dsx_i2c_probe,
        .id_table = st_lsm6dsx_i2c_id_table,

Hi Jonathan,

Thank you. The driver has evolved quite a bit in 6.2 (I read somewhere that 6.2 includes some i2c enhancements), but I adapted your changes to fit my Debian 6.1 kernel and it works. Two IIO devices are created in sysfs, iio-sensor-proxy.service starts up and automatic screen rotation in Gnome just works.

To get the modules to load on boot, I made a small change to your code in st_lsm6dsx_i2c to add the acpi alias to modules.alias:

adding a null element to st_lsm6dsx_i2c_acpi_match:

    static const struct acpi_device_id st_lsm6dsx_i2c_acpi_match[] = {
         { "SMO8B30", ST_LSM6DS3TRC_ID, },
         { },
    };

then:

   MODULE_DEVICE_TABLE(acpi, st_lsm6dsx_i2c_acpi_match);

dmesg shows:

[ 7366.120208] st_lsm6dsx_i2c i2c-SMO8B30:00: supply vdd not found, using dummy regulator
[ 7366.120260] st_lsm6dsx_i2c i2c-SMO8B30:00: supply vddio not found, using dummy regulator
[ 7366.650839] st_lsm6dsx_i2c i2c-SMO8B30:00: mounting matrix not found: using identity...

Is this a problem?

Thanks again.

Darrell