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> --- 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; /* * Register i2c-bus notifier + queue initial scan for lis3lv02d -- 2.47.1
