From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jae Hyun Yoo Date: Fri, 21 Sep 2018 10:46:34 -0700 Subject: [PATCH] i2c: aspeed: fixed invalid clock parameters for very large divisors In-Reply-To: <20180920232820.243734-1-brendanhiggins@google.com> References: <20180920232820.243734-1-brendanhiggins@google.com> Message-ID: <07af0253-1efc-2ae1-93fb-ebcc1996d768@linux.intel.com> List-Id: To: linux-aspeed@lists.ozlabs.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 [....] > + 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