On Mon, 9 Dec 2024, Hans de Goede wrote: > Unfortunately the SMOxxxx ACPI device does not contain the i2c-address > of the accelerometer. So a DMI product-name to address mapping table > is used. > > At support to have the kernel probe for the i2c-address for modesl > which are not on the list. > > The new probing code sits behind a new probe_i2c_addr module parameter, > which is disabled by default because probing might be dangerous. > > Link: https://lore.kernel.org/linux-i2c/4820e280-9ca4-4d97-9d21-059626161bfc@xxxxxxxxxxxxx/ > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> So what was the result of the private inquiry to Dell? Did they respond? Did they provide useful info? > Changes in v8: > - Use dev_err() / dev_dbg() where possible using &adap->dev as the device > for logging > > Changes in v6: > - Use i2c_new_scanned_device() instead of re-inventing it > > Changes in v5: > - Add "this may be dangerous warning" to MODULE_PARM_DESC(probe_i2c_addr) > --- > drivers/platform/x86/dell/dell-lis3lv02d.c | 53 ++++++++++++++++++++-- > 1 file changed, 49 insertions(+), 4 deletions(-) > > diff --git a/drivers/platform/x86/dell/dell-lis3lv02d.c b/drivers/platform/x86/dell/dell-lis3lv02d.c > index d2b34e10c5eb..8d9dc59c7d8c 100644 > --- a/drivers/platform/x86/dell/dell-lis3lv02d.c > +++ b/drivers/platform/x86/dell/dell-lis3lv02d.c > @@ -15,6 +15,8 @@ > #include <linux/workqueue.h> > #include "dell-smo8800-ids.h" > > +#define LIS3_WHO_AM_I 0x0f > + > #define DELL_LIS3LV02D_DMI_ENTRY(product_name, i2c_addr) \ > { \ > .matches = { \ > @@ -57,6 +59,39 @@ static u8 i2c_addr; > static struct i2c_client *i2c_dev; > static bool notifier_registered; > > +static bool probe_i2c_addr; > +module_param(probe_i2c_addr, bool, 0444); > +MODULE_PARM_DESC(probe_i2c_addr, "Probe the i801 I2C bus for the accelerometer on models where the address is unknown, this may be dangerous."); > + > +static int detect_lis3lv02d(struct i2c_adapter *adap, unsigned short addr) > +{ > + union i2c_smbus_data smbus_data; > + int err; > + > + dev_info(&adap->dev, "Probing for lis3lv02d on address 0x%02x\n", addr); > + > + err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, LIS3_WHO_AM_I, > + I2C_SMBUS_BYTE_DATA, &smbus_data); > + if (err < 0) > + return 0; /* Not found */ > + > + /* valid who-am-i values are from drivers/misc/lis3lv02d/lis3lv02d.c */ > + switch (smbus_data.byte) { > + case 0x32: > + case 0x33: > + case 0x3a: > + case 0x3b: > + break; > + default: > + dev_warn(&adap->dev, "Unknown who-am-i register value 0x%02x\n", > + smbus_data.byte); > + return 0; /* Not found */ > + } > + > + dev_dbg(&adap->dev, "Detected lis3lv02d on address 0x%02x\n", addr); > + return 1; /* Found */ > +} > + > static bool i2c_adapter_is_main_i801(struct i2c_adapter *adap) > { > /* > @@ -97,10 +132,18 @@ static void instantiate_i2c_client(struct work_struct *work) > if (!adap) > return; > > - info.addr = i2c_addr; > strscpy(info.type, "lis3lv02d", I2C_NAME_SIZE); > > - i2c_dev = i2c_new_client_device(adap, &info); > + if (i2c_addr) { > + info.addr = i2c_addr; > + i2c_dev = i2c_new_client_device(adap, &info); > + } else { > + /* First try address 0x29 (most used) and then try 0x1d */ > + static const unsigned short addr_list[] = { 0x29, 0x1d, I2C_CLIENT_END }; > + > + i2c_dev = i2c_new_scanned_device(adap, &info, addr_list, detect_lis3lv02d); > + } > + > if (IS_ERR(i2c_dev)) { > dev_err(&adap->dev, "error %ld registering i2c_client\n", PTR_ERR(i2c_dev)); > i2c_dev = NULL; > @@ -169,12 +212,14 @@ static int __init dell_lis3lv02d_init(void) > put_device(dev); > > lis3lv02d_dmi_id = dmi_first_match(lis3lv02d_devices); > - if (!lis3lv02d_dmi_id) { > + if (!lis3lv02d_dmi_id && !probe_i2c_addr) { > pr_warn("accelerometer is present on SMBus but its address is unknown, skipping registration\n"); > + pr_info("Pass dell_lis3lv02d.probe_i2c_addr=1 on the kernel commandline to probe, this may be dangerous!\n"); > return 0; > } > > - i2c_addr = (long)lis3lv02d_dmi_id->driver_data; > + if (lis3lv02d_dmi_id) > + i2c_addr = (long)lis3lv02d_dmi_id->driver_data; If somebody enables this parameter and it successfully finds a device, shouldn't the user be instructed to report the info so that new entries can be added and the probe parameter is no longer needed in those case? -- i.
