Hi, Linus, Wolfram,
On 06/05/2018 04:49 PM, Linus Walleij wrote:
The Atmel ECC driver contains a check for the I2C bus clock
frequency, so as to check that the I2C adapter in use
satisfies the device specs.
If the device is connected to a device tree node that does not
contain a clock frequency setting, such as an I2C mux or gate,
this blocks the probe. Make the probe continue silently if
no clock frequency can be found, assuming all is safe.
I don't think it's safe. We use bus_clk_rate to compute the ecc508's
wake token. If you can't wake the device, it will ignore all your
commands.
My proposal was to introduce a bus_freq_hz member in the i2c_adapter
structure (https://patchwork.kernel.org/patch/10307637/), but I haven't
received feedback yet, Wolfram?
I would say first to check the bus_freq_hz from adapter (if it will be
accepted) else to look into dt and, in the last case, if nowhere
provided, to block the probe.
Thanks,
ta
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/crypto/atmel-ecc.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
index e66f18a0ddd0..145ab3a39a56 100644
--- a/drivers/crypto/atmel-ecc.c
+++ b/drivers/crypto/atmel-ecc.c
@@ -657,14 +657,13 @@ static int atmel_ecc_probe(struct i2c_client *client,
return -ENODEV;
}
+ /*
+ * Silently assume all is fine if there is no
+ * "clock-frequency" property.
+ */
ret = of_property_read_u32(client->adapter->dev.of_node,
"clock-frequency", &bus_clk_rate);
- if (ret) {
- dev_err(dev, "of: failed to read clock-frequency property\n");
- return ret;
- }
-
- if (bus_clk_rate > 1000000L) {
+ if (!ret && (bus_clk_rate > 1000000L)) {
dev_err(dev, "%d exceeds maximum supported clock frequency (1MHz)\n",
bus_clk_rate);
return -EINVAL;
