Hi, Linus,
On 06/28/2018 04:07 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 with a warning
> if no clock frequency can be found, assuming it is safe.
>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> ChangeLog v1->v2:
> - Instead of silently ignoring the missing clock frequency,
> issue a warning and continue.
> ---
> drivers/crypto/atmel-ecc.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/crypto/atmel-ecc.c b/drivers/crypto/atmel-ecc.c
> index e66f18a0ddd0..33773920e4bf 100644
> --- a/drivers/crypto/atmel-ecc.c
> +++ b/drivers/crypto/atmel-ecc.c
> @@ -659,12 +659,9 @@ static int atmel_ecc_probe(struct i2c_client *client,
>
> 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)
> + dev_warn(dev, "i2c host missing clock frequency information\n");
Not ok, bus_clk_rate is used to compute the wake_token. If you can't find the
clock-frequency then you will use the stack value of bus_clk_rate. If you don't
want to break the probe, then I propose to do the same assumption that is done
in i2c buses when clock-frequency is not found: assume it is 100kHZ. Although,
personally, I don't like this assumption and that's why I proposed that patch to
Wolfram. Nevertheless, let's do what we can in this conditions: make the same
assumption.
Thanks,
ta
> + else if (bus_clk_rate > 1000000L) {
> dev_err(dev, "%d exceeds maximum supported clock frequency (1MHz)\n",
> bus_clk_rate);
> return -EINVAL;
>
