| Message ID | 20240726-topic-fs4480_check-v2-1-901ca449db15@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] usb: typec: fsa4480: Check if the chip is really there | expand |
On Fri, Jul 26, 2024 at 01:43:30PM +0200, Konrad Dybcio wrote: > From: Konrad Dybcio <konrad.dybcio@linaro.org> > > 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") > Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org> > Signed-off-by: Konrad Dybcio <konradybcio@kernel.org> You can't sign off on a patch twice, that makes no sense, sorry. greg k-h
On Fri, Jul 26, 2024 at 03:52:22PM +0200, Konrad Dybcio wrote: > > > On 26.07.2024 3:12 PM, Greg Kroah-Hartman wrote: > > On Fri, Jul 26, 2024 at 01:43:30PM +0200, Konrad Dybcio wrote: > >> From: Konrad Dybcio <konrad.dybcio@linaro.org> > >> > >> 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") > >> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org> > >> Signed-off-by: Konrad Dybcio <konradybcio@kernel.org> > > You can't sign off on a patch twice, that makes no sense, sorry. > > I'm losing access to the @linaro.org email and want to preserve the > authorship there (as this patch was developed during work hours). > > Then, the author's email doesn't match the sender's email, so I'm > expected to sign off with the sender's one. > > Should I assume that the maintainer trusts me to be the same person? Yes I do :)
On Fri, Jul 26, 2024 at 01:43:30PM GMT, Konrad Dybcio wrote: > From: Konrad Dybcio <konrad.dybcio@linaro.org> > > 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) So wonderful to have 0 Vendor ID (initially assumed that you are showing it as an example of an error). But yes, the datasheet has 0 there. > > [1] https://www.onsemi.com/pdf/datasheet/fsa4480-d.pdf > > Fixes: 1dc246320c6b ("usb: typec: mux: Add On Semi fsa4480 driver") > Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org> > Signed-off-by: Konrad Dybcio <konradybcio@kernel.org> > --- > 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@linaro.org > --- > drivers/usb/typec/mux/fsa4480.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) With the S-o-B tags fixed: Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
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;