On Mon, Jul 29, 2024 at 10:42:58AM +0200, Konrad Dybcio wrote: > From: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> > > Currently, the driver will happily register the switch/mux devices, and > so long as the i2c master doesn't complain, the user would never know > there's something wrong. > > Add a device id check (based on [1]) and return -ENODEV if the read > fails or returns nonsense. > > Checking the value on a Qualcomm SM6115P-based Lenovo Tab P11 tablet, > the ID mentioned in the datasheet does indeed show up: > fsa4480 1-0042: Found FSA4480 v1.1 (Vendor ID = 0) > > [1] https://www.onsemi.com/pdf/datasheet/fsa4480-d.pdf > > Fixes: 1dc246320c6b ("usb: typec: mux: Add On Semi fsa4480 driver") > Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> > Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > --- > Changes in v3: > - Don't sign off twice > - Pick up Dmitry's rb > - Link to v2: https://lore.kernel.org/r/20240726-topic-fs4480_check-v2-1-901ca449db15@xxxxxxxxxx > > Changes in v2: > - Prepend the new defines with FSA4480_ to make them more obvious > - Link to v1: https://lore.kernel.org/r/20240212-topic-fs4480_check-v1-1-d9969e4d6f9a@xxxxxxxxxx > --- > drivers/usb/typec/mux/fsa4480.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/usb/typec/mux/fsa4480.c b/drivers/usb/typec/mux/fsa4480.c > index cb7cdf90cb0a..cd235339834b 100644 > --- a/drivers/usb/typec/mux/fsa4480.c > +++ b/drivers/usb/typec/mux/fsa4480.c > @@ -13,6 +13,10 @@ > #include <linux/usb/typec_dp.h> > #include <linux/usb/typec_mux.h> > > +#define FSA4480_DEVICE_ID 0x00 > + #define FSA4480_DEVICE_ID_VENDOR_ID GENMASK(7, 6) > + #define FSA4480_DEVICE_ID_VERSION_ID GENMASK(5, 3) > + #define FSA4480_DEVICE_ID_REV_ID GENMASK(2, 0) > #define FSA4480_SWITCH_ENABLE 0x04 > #define FSA4480_SWITCH_SELECT 0x05 > #define FSA4480_SWITCH_STATUS1 0x07 > @@ -251,6 +255,7 @@ static int fsa4480_probe(struct i2c_client *client) > struct typec_switch_desc sw_desc = { }; > struct typec_mux_desc mux_desc = { }; > struct fsa4480 *fsa; > + int val = 0; > int ret; > > fsa = devm_kzalloc(dev, sizeof(*fsa), GFP_KERNEL); > @@ -268,6 +273,15 @@ static int fsa4480_probe(struct i2c_client *client) > if (IS_ERR(fsa->regmap)) > return dev_err_probe(dev, PTR_ERR(fsa->regmap), "failed to initialize regmap\n"); > > + ret = regmap_read(fsa->regmap, FSA4480_DEVICE_ID, &val); > + if (ret || !val) > + return dev_err_probe(dev, -ENODEV, "FSA4480 not found\n"); > + > + dev_dbg(dev, "Found FSA4480 v%lu.%lu (Vendor ID = %lu)\n", > + FIELD_GET(FSA4480_DEVICE_ID_VERSION_ID, val), > + FIELD_GET(FSA4480_DEVICE_ID_REV_ID, val), > + FIELD_GET(FSA4480_DEVICE_ID_VENDOR_ID, val)); > + > /* Safe mode */ > fsa->cur_enable = FSA4480_ENABLE_DEVICE | FSA4480_ENABLE_USB; > fsa->mode = TYPEC_STATE_SAFE; thanks, -- heikki
