From: Konrad Dybcio <konrad.dybcio@linaro.org>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bjorn Andersson <andersson@kernel.org>
Cc: Marijn Suijten <marijn.suijten@somainline.org>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Konrad Dybcio <konrad.dybcio@linaro.org>
Subject: [PATCH] usb: typec: fsa4480: Check if the chip is really there
Date: Mon, 12 Feb 2024 13:01:30 +0100 [thread overview]
Message-ID: <20240212-topic-fs4480_check-v1-1-d9969e4d6f9a@linaro.org> (raw)
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>
---
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..d622f4f3bd54 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 DEVICE_ID_VENDOR_ID GENMASK(7, 6)
+ #define DEVICE_ID_VERSION_ID GENMASK(5, 3)
+ #define 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(DEVICE_ID_VERSION_ID, val),
+ FIELD_GET(DEVICE_ID_REV_ID, val),
+ FIELD_GET(DEVICE_ID_VENDOR_ID, val));
+
/* Safe mode */
fsa->cur_enable = FSA4480_ENABLE_DEVICE | FSA4480_ENABLE_USB;
fsa->mode = TYPEC_STATE_SAFE;
---
base-commit: ae00c445390b349e070a64dc62f08aa878db7248
change-id: 20240212-topic-fs4480_check-caa0160fb101
Best regards,
--
Konrad Dybcio <konrad.dybcio@linaro.org>
next reply other threads:[~2024-02-12 12:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 12:01 Konrad Dybcio [this message]
2024-02-12 12:48 ` [PATCH] usb: typec: fsa4480: Check if the chip is really there Greg Kroah-Hartman
2024-02-12 12:59 ` Konrad Dybcio
2024-02-13 9:45 ` Greg Kroah-Hartman
2024-02-12 12:48 ` Greg Kroah-Hartman
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