From: alexandre.belloni@free-electrons•com (Alexandre Belloni)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/2] clk: at91: usb: fix at91sam9x5 recalc, round and set rate
Date: Fri, 7 Nov 2014 18:51:39 +0100 [thread overview]
Message-ID: <20141107175139.GF4068@piout.net> (raw)
In-Reply-To: <1415179995-25062-3-git-send-email-boris.brezillon@free-electrons.com>
On 05/11/2014 at 10:33:15 +0100, Boris Brezillon wrote :
> First check for rate == 0 in set_rate and round_rate to avoid div by zero.
> Then, in order to get the closest rate, round all divisions to the closest
> result instead of rounding them down.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons•com>
> ---
> drivers/clk/at91/clk-usb.c | 29 +++++++++++++++++------------
> 1 file changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/clk/at91/clk-usb.c b/drivers/clk/at91/clk-usb.c
> index 5b3b63c..7980e8c 100644
> --- a/drivers/clk/at91/clk-usb.c
> +++ b/drivers/clk/at91/clk-usb.c
> @@ -52,7 +52,8 @@ static unsigned long at91sam9x5_clk_usb_recalc_rate(struct clk_hw *hw,
>
> tmp = pmc_read(pmc, AT91_PMC_USB);
> usbdiv = (tmp & AT91_PMC_OHCIUSBDIV) >> SAM9X5_USB_DIV_SHIFT;
> - return parent_rate / (usbdiv + 1);
> +
> + return DIV_ROUND_CLOSEST(parent_rate, (usbdiv + 1));
> }
>
> static long at91sam9x5_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
> @@ -62,19 +63,19 @@ static long at91sam9x5_clk_usb_round_rate(struct clk_hw *hw, unsigned long rate,
> unsigned long bestrate;
> unsigned long tmp;
>
> + if (!rate)
> + return DIV_ROUND_CLOSEST(*parent_rate, SAM9X5_USB_MAX_DIV + 1);
> +
Maybe I'm missing something but I would return -EINVAL here.
> if (rate >= *parent_rate)
> return *parent_rate;
>
> - div = *parent_rate / rate;
> - if (div >= SAM9X5_USB_MAX_DIV)
> - return *parent_rate / (SAM9X5_USB_MAX_DIV + 1);
> + div = DIV_ROUND_CLOSEST(*parent_rate, rate);
> + if (div > SAM9X5_USB_MAX_DIV + 1)
> + div = SAM9X5_USB_MAX_DIV + 1;
> + else if (!div)
> + div = 1;
In that case, you are also screwed, I would return -EINVAL.
>
> - bestrate = *parent_rate / div;
> - tmp = *parent_rate / (div + 1);
> - if (bestrate - rate > rate - tmp)
> - bestrate = tmp;
> -
> - return bestrate;
> + return DIV_ROUND_CLOSEST(*parent_rate, div);
> }
>
> static int at91sam9x5_clk_usb_set_parent(struct clk_hw *hw, u8 index)
> @@ -106,9 +107,13 @@ static int at91sam9x5_clk_usb_set_rate(struct clk_hw *hw, unsigned long rate,
> u32 tmp;
> struct at91sam9x5_clk_usb *usb = to_at91sam9x5_clk_usb(hw);
> struct at91_pmc *pmc = usb->pmc;
> - unsigned long div = parent_rate / rate;
> + unsigned long div;
>
> - if (parent_rate % rate || div < 1 || div >= SAM9X5_USB_MAX_DIV)
> + if (!rate)
> + return -EINVAL;
> +
> + div = DIV_ROUND_CLOSEST(parent_rate, rate);
> + if (div > SAM9X5_USB_MAX_DIV + 1 || !div)
> return -EINVAL;
>
> tmp = pmc_read(pmc, AT91_PMC_USB) & ~AT91_PMC_OHCIUSBDIV;
> --
> 1.9.1
>
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2014-11-07 17:51 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-05 9:33 [PATCH 0/2] clk: at91: usb: rate calculation fixes Boris Brezillon
2014-11-05 9:33 ` [PATCH 1/2] clk: at91: usb: fix at91rm9200 round and set rate Boris Brezillon
2014-11-05 13:12 ` Andreas Henriksson
2014-11-05 9:33 ` [PATCH 2/2] clk: at91: usb: fix at91sam9x5 recalc, " Boris Brezillon
2014-11-07 17:51 ` Alexandre Belloni [this message]
2014-11-07 17:58 ` Boris Brezillon
2014-11-05 17:13 ` [PATCH 0/2] clk: at91: usb: rate calculation fixes Nicolas Ferre
2014-11-05 18:12 ` Boris Brezillon
2014-11-13 10:59 ` Nicolas Ferre
2014-11-14 18:12 ` Mike Turquette
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