On Wed, 8 Dec 2021 16:33:52 +0200 Nikos Latmos <n.latmos@xxxxxxxxxx> wrote: > Hello, > > I have an ARM device based on the Broadcom BCM2837 processor (quad-core > ARM Cortex-A53, 1.2GHz), which has an Invensense ICM-42605 IMU chip > connected over I2C. I'm running an unmodified Linux 5.4.83 kernel. The I2C > driver for my device is in the following path: > drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c. > > The problem is that the device driver cannot be probed. More specifically, > dmesg returns the following error message: > > inv-icm42600-i2c 0-0068: mounting matrix not found: using identity... > inv-icm42600-i2c 0-0068: 0-0068 supply vdd not found, using dummy regulator > inv-icm42600-i2c 0-0068: 0-0068 supply vddio not found, using dummy regulator > inv-icm42600-i2c: probe of 0-0068 failed with error -121 > > During the debugging procedure, I found out that the failure occurred when > the driver tried to set up the I2C bus parameters. More precisely, by setting > the INV_ICM42600_REG_INTF_CONFIG6 register according to the values described > in the datasheet for the I2C communication, actually caused the probe function > to fail and return the error -121. > > After I experimented with different values in the specific register bits, > I came to the conclusion, that the setting of the bit > INV_ICM42600_INTF_CONFIG6_I3C_SDR_EN caused the system to successfully > probe the driver. Any other bit setting combinations failed to do so. > > Any hints on why would the driver behave so? > > Here is a patch that I have so far and it seems to solve the issue. > > Best regards, > Nick Latmos Hi All, Anyone familiar with this part able to help Nick? Thanks, Jonathan > > > From d7b3922cd0182ba880ff729edb4a156b55dfb6f0 Mon Sep 17 00:00:00 2001 > From: nicklat <n.latmos@xxxxxxxxxx> > Date: Wed, 8 Dec 2021 15:51:28 +0200 > Subject: [PATCH] iio: imu: inv_icm42600: enable SDR mode > > Add SDR (Single Data Rate) support. > In SDR mode, data is only clocked on one edge of the clock. > > Without this option enabled, the probing process fails. > > Signed-off-by: nicklat <n.latmos@xxxxxxxxxx> > --- > drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c > b/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c > index 85b1934cec60..ea31f102fbca 100644 > --- a/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c > +++ b/drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c > @@ -21,7 +21,8 @@ static int inv_icm42600_i2c_bus_setup(struct > inv_icm42600_state *st) > /* setup interface registers */ > ret = regmap_update_bits(st->map, INV_ICM42600_REG_INTF_CONFIG6, > INV_ICM42600_INTF_CONFIG6_MASK, > - INV_ICM42600_INTF_CONFIG6_I3C_EN); > + INV_ICM42600_INTF_CONFIG6_I3C_EN | > + INV_ICM42600_INTF_CONFIG6_I3C_SDR_EN); > if (ret) > return ret; > > -- > 2.25.1
