From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guru Das Srinagesh Subject: Re: [PATCH v12 10/11] clk: pwm: Use 64-bit division function Date: Fri, 10 Apr 2020 12:15:03 -0700 Message-ID: <20200410191503.GA21571@codeaurora.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: linux-pwm@vger.kernel.org Cc: Thierry Reding , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , Subbaraman Narayanamurthy , David Collins , linux-kernel@vger.kernel.org, Michael Turquette , Stephen Boyd , linux-clk@vger.kernel.org, David Laight , Arnd Bergmann List-Id: linux-pwm@vger.kernel.org + Arnd, David On Wed, Apr 08, 2020 at 11:52:39PM -0700, Guru Das Srinagesh wrote: > Since the PWM framework is switching struct pwm_args.period's datatype > to u64, prepare for this transition by using div64_u64 to handle a > 64-bit divisor. > > Also ensure that divide-by-zero (with fixed_rate as denominator) does > not happen with an explicit check with probe failure as a consequence. > > Cc: Michael Turquette > Cc: Stephen Boyd > Cc: linux-clk@vger.kernel.org > > Signed-off-by: Guru Das Srinagesh > --- > drivers/clk/clk-pwm.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c > index 87fe0b0e..86f2e2d 100644 > --- a/drivers/clk/clk-pwm.c > +++ b/drivers/clk/clk-pwm.c > @@ -89,7 +89,12 @@ static int clk_pwm_probe(struct platform_device *pdev) > } > > if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate)) > - clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period; > + clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period); > + > + if (!clk_pwm->fixed_rate) { > + dev_err(&pdev->dev, "fixed_rate cannot be zero\n"); > + return -EINVAL; > + } > > if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate && > pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) { > -- Hello Arnd, David: Sorry, missed cc-ing you both to this patch while sending it out. Could you please review it when you get a chance to? Thank you. Guru Das.