From: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
To: linux-aspeed@lists.ozlabs.org
Subject: [PATCH] i2c: aspeed: fixed invalid clock parameters for very large divisors
Date: Fri, 21 Sep 2018 10:46:34 -0700 [thread overview]
Message-ID: <07af0253-1efc-2ae1-93fb-ebcc1996d768@linux.intel.com> (raw)
In-Reply-To: <20180920232820.243734-1-brendanhiggins@google.com>
Hi Brendan,
nit:
Title in imperative mood. I'd put 'fix' instead of 'fixed'.
On 9/20/2018 4:28 PM, Brendan Higgins wrote:
> The function that computes clock parameters from divisors did not
> respect the maximum size of the bitfields that the parameters were
> written to. This fixes the bug.
>
> This bug can be reproduced with (and this fix verified with) the test
> at: https://kunit-review.googlesource.com/c/linux/+/1035/
>
> Discovered-by-KUnit: https://kunit-review.googlesource.com/c/linux/+/1035/
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
[....]
> + if (base_clk > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) {
> + base_clk = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK;
> + clk_low = clk_high_low_mask;
> + clk_high = clk_high_low_mask;
Yes, it fixes these parameters to the lowest bus speed setting with the
maximum base clock divisor value and the maximum SCL timing cycle value
when a low bus-frequency is requested which exceeds the range of this
H/W supports. This exceptional case handling is needed to prevent making
invalid settings on it. Nice fix!
One minor issue is, 'base_clk_divisor' instead of 'base_clk' could avoid
misreading on this code.
With that, it looks nice to me. Thanks!
Reviewed-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
next prev parent reply other threads:[~2018-09-21 17:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 23:28 [PATCH] i2c: aspeed: fixed invalid clock parameters for very large divisors Brendan Higgins
2018-09-21 17:46 ` Jae Hyun Yoo [this message]
2018-09-21 22:18 ` Brendan Higgins
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