Date:   Wed, 15 Feb 2023 14:24:15 +0200
From:   Abel Vesa <abel.vesa@linaro.org>
To:     Kevin Groeneveld <kgroeneveld@lenbrook.com>
Cc:     Abel Vesa <abelvesa@kernel.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] clk: imx: pll14xx: fix recalc_rate for negative kdiv
Message-ID: <Y+zO7/GBurZwihOJ@linaro.org>
References: <20221210203835.9714-1-kgroeneveld@lenbrook.com>
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On 22-12-10 15:38:35, Kevin Groeneveld wrote:
> kdiv is a signed 16 bit value in the DEV_CTL1 register. Commit
> 53990cf9d5b4 ("clk: imx: pll14xx: consolidate rate calculation") changed
> the kdiv variable from a short int to just int. When the value read from
> the DIV_CTL1 register is assigned directly to an int the sign of the value
> is lost resulting in incorrect results when the value is negative. Adding
> a s16 cast to the register value fixes the issue.
> 
> Fixes: 53990cf9d5b4 ("clk: imx: pll14xx: consolidate rate calculation")
> Signed-off-by: Kevin Groeneveld <kgroeneveld@lenbrook.com>

Reviewed-by: Abel Vesa <abel.vesa@linaro.org>

Stephen, can you pick this up through fixes?
> ---
>  drivers/clk/imx/clk-pll14xx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c
> index 1d0f79e9c346..d12194d17b10 100644
> --- a/drivers/clk/imx/clk-pll14xx.c
> +++ b/drivers/clk/imx/clk-pll14xx.c
> @@ -254,7 +254,7 @@ static unsigned long clk_pll14xx_recalc_rate(struct clk_hw *hw,
>  
>  	if (pll->type == PLL_1443X) {
>  		pll_div_ctl1 = readl_relaxed(pll->base + DIV_CTL1);
> -		kdiv = FIELD_GET(KDIV_MASK, pll_div_ctl1);
> +		kdiv = (s16)FIELD_GET(KDIV_MASK, pll_div_ctl1);
>  	} else {
>  		kdiv = 0;
>  	}
> -- 
> 2.17.1
>