From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 25 Jul 2017 17:32:08 -0700 From: Stephen Boyd To: Peter De Schrijver Cc: Michael Turquette , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, Alex Frid Subject: Re: [PATCH] clk: Don't write error code into divider register Message-ID: <20170726003208.GF2146@codeaurora.org> References: <1500977920-5533-1-git-send-email-pdeschrijver@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1500977920-5533-1-git-send-email-pdeschrijver@nvidia.com> List-ID: On 07/25, Peter De Schrijver wrote: > From: Alex Frid > > Add a check for error returned by divider value calculation to avoid > writing error code into hw register. > > Signed-off-by: Alex Frid > Reviewed-by: Peter De Schrijver > Reviewed-by: Jon Mayo > --- Fixes: bca9690b9426 ("clk: divider: Make generic for usage elsewhere") perhaps? Also, curious how this got triggered? Presumably round_rate would have failed before a set_rate call with something invalid came through so that's why nobody has reported anything so far. > drivers/clk/clk-divider.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index 9bb472c..4ed516c 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -385,12 +385,14 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, > unsigned long parent_rate) > { > struct clk_divider *divider = to_clk_divider(hw); > - unsigned int value; > + int value; > unsigned long flags = 0; > u32 val; > > value = divider_get_val(rate, parent_rate, divider->table, > divider->width, divider->flags); > + if (value < 0) Perhaps value should be an s32 if we're doing a writel with it shifted so much. And then, we could declare it as a u32 and test it with if ((s32)value < 0) to see if there was an error. Sort of annoying that we've limited the available space of divider_get_val() by combining the value with the error code number space. We may want to not do that in case people have huge dividers. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project