linux-kernel - Re: [PATCH] drivers: clk: zynqmp: Allow zero divisor value

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Message-ID: <15f0f82f-0607-4cf5-f5a5-5edd7c5321bc@xilinx.com>
Date:   Mon, 18 Mar 2019 13:48:52 +0100
From:   Michal Simek <michal.simek@...inx.com>
To:     Jolly Shah <jolly.shah@...inx.com>, <mturquette@...libre.com>,
        <sboyd@...eaurora.org>, <michal.simek@...inx.com>,
        <linux-clk@...r.kernel.org>
CC:     <rajanv@...inx.com>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, Rajan Vaja <rajan.vaja@...inx.com>,
        Jolly Shah <jollys@...inx.com>
Subject: Re: [PATCH] drivers: clk: zynqmp: Allow zero divisor value

On 05. 03. 19 0:27, Jolly Shah wrote:
> From: Rajan Vaja <rajan.vaja@...inx.com>
> 
> Zero divider is valid and default for some of ZynqMP
> clocks. Allow zero divisor when CLK_DIVIDER_ALLOW_ZERO
> for the clock is set.
> 
> Signed-off-by: Rajan Vaja <rajanv@...inx.com>
> Signed-off-by: Jolly Shah <jollys@...inx.com>
> ---
>  drivers/clk/zynqmp/divider.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/clk/zynqmp/divider.c b/drivers/clk/zynqmp/divider.c
> index a371c66..e146b6f 100644
> --- a/drivers/clk/zynqmp/divider.c
> +++ b/drivers/clk/zynqmp/divider.c
> @@ -76,6 +76,13 @@ static unsigned long zynqmp_clk_divider_recalc_rate(struct clk_hw *hw,
>  	else
>  		value = div >> 16;
>  
> +	if (!value) {
> +		WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
> +		     "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
> +		     clk_name);
> +		return parent_rate;
> +	}
> +
>  	return DIV_ROUND_UP_ULL(parent_rate, value);
>  }
>  
> 

Stephen: Do you want to take it via your tree?

Thanks,
Michal