netdev - Re: [PATCH] rcar_can: support all input clocks

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Date:	Wed, 30 Jul 2014 09:32:14 +0200
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
	netdev@...r.kernel.org, wg@...ndegger.com,
	linux-can@...r.kernel.org
CC:	linux-sh@...r.kernel.org, vksavl@...il.com
Subject: Re: [PATCH] rcar_can: support all input clocks

On 07/29/2014 11:45 PM, Sergei Shtylyov wrote:
> When writing the driver, I didn't give enough attention to the possible sources
> of the CAN clock: although the value of the CLKR register was specified by  the
> platform data, the driver only handled one case, that is CAN clock being sourced
> from the clkp1 clock, the same that clocks the whole CAN module. In order to fix
> that overlook, we'll have to handle the CAN clock separately from the peripheral
> clock (however, clkp1 will be specified for a CAN device only once)...
> 
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@...entembedded.com>

Looks good, nitpick inline:
> 
> ---
> The patch is against the 'linux-can-next.git' repo, however it's a fix, not a
> cleanup.
> 
>  drivers/net/can/rcar_can.c |   39 ++++++++++++++++++++++++++++++++++-----
>  1 file changed, 34 insertions(+), 5 deletions(-)
> 
> Index: linux-can-next/drivers/net/can/rcar_can.c
> ===================================================================
> --- linux-can-next.orig/drivers/net/can/rcar_can.c
> +++ linux-can-next/drivers/net/can/rcar_can.c
> @@ -87,6 +87,7 @@ struct rcar_can_priv {
>  	struct napi_struct napi;
>  	struct rcar_can_regs __iomem *regs;
>  	struct clk *clk;
> +	struct clk *can_clk;
>  	u8 tx_dlc[RCAR_CAN_FIFO_DEPTH];
>  	u32 tx_head;
>  	u32 tx_tail;
> @@ -505,14 +506,20 @@ static int rcar_can_open(struct net_devi
>  
>  	err = clk_prepare_enable(priv->clk);
>  	if (err) {
> -		netdev_err(ndev, "clk_prepare_enable() failed, error %d\n",
> +		netdev_err(ndev, "failed to enable periperal clock, error %d\n",
>  			   err);
>  		goto out;
>  	}
> +	err = clk_prepare_enable(priv->can_clk);
> +	if (err) {
> +		netdev_err(ndev, "failed to enable CAN clock, error %d\n",
> +			   err);
> +		goto out_clock;
> +	}
>  	err = open_candev(ndev);
>  	if (err) {
>  		netdev_err(ndev, "open_candev() failed, error %d\n", err);
> -		goto out_clock;
> +		goto out_can_clock;
>  	}
>  	napi_enable(&priv->napi);
>  	err = request_irq(ndev->irq, rcar_can_interrupt, 0, ndev->name, ndev);
> @@ -527,6 +534,8 @@ static int rcar_can_open(struct net_devi
>  out_close:
>  	napi_disable(&priv->napi);
>  	close_candev(ndev);
> +out_can_clock:
> +	clk_disable_unprepare(priv->can_clk);
>  out_clock:
>  	clk_disable_unprepare(priv->clk);
>  out:
> @@ -565,6 +574,7 @@ static int rcar_can_close(struct net_dev
>  	rcar_can_stop(ndev);
>  	free_irq(ndev->irq, ndev);
>  	napi_disable(&priv->napi);
> +	clk_disable_unprepare(priv->can_clk);
>  	clk_disable_unprepare(priv->clk);
>  	close_candev(ndev);
>  	can_led_event(ndev, CAN_LED_EVENT_STOP);
> @@ -715,6 +725,12 @@ static int rcar_can_get_berr_counter(con
>  	return 0;
>  }
>  
> +static const char * const clock_names[] = {
> +	[CLKR_CLKP1]	= "clkp1",
> +	[CLKR_CLKP2]	= "clkp2",
> +	[CLKR_CLKEXT]	= "can_clk",
> +};
> +
>  static int rcar_can_probe(struct platform_device *pdev)
>  {
>  	struct rcar_can_platform_data *pdata;
> @@ -753,10 +769,23 @@ static int rcar_can_probe(struct platfor
>  
>  	priv = netdev_priv(ndev);
>  
> -	priv->clk = devm_clk_get(&pdev->dev, NULL);
> +	priv->clk = devm_clk_get(&pdev->dev, "clkp1");
>  	if (IS_ERR(priv->clk)) {
>  		err = PTR_ERR(priv->clk);
> -		dev_err(&pdev->dev, "cannot get clock: %d\n", err);
> +		dev_err(&pdev->dev, "cannot get peripheral clock: %d\n", err);
> +		goto fail_clk;
> +	}
> +
> +	if (pdata->clock_select > CLKR_CLKEXT) {

Please use ARRAY_SIZE instead of CLKR_CLKEXT.

> +		err = -EINVAL;
> +		dev_err(&pdev->dev, "invalid CAN clock selected\n");
> +		goto fail_clk;
> +	}
> +	priv->can_clk = devm_clk_get(&pdev->dev,
> +				     clock_names[pdata->clock_select]);
> +	if (IS_ERR(priv->can_clk)) {
> +		err = PTR_ERR(priv->can_clk);
> +		dev_err(&pdev->dev, "cannot get CAN clock: %d\n", err);
>  		goto fail_clk;
>  	}
>  
> @@ -766,7 +795,7 @@ static int rcar_can_probe(struct platfor
>  	priv->ndev = ndev;
>  	priv->regs = addr;
>  	priv->clock_select = pdata->clock_select;
> -	priv->can.clock.freq = clk_get_rate(priv->clk);
> +	priv->can.clock.freq = clk_get_rate(priv->can_clk);
>  	priv->can.bittiming_const = &rcar_can_bittiming_const;
>  	priv->can.do_set_mode = rcar_can_do_set_mode;
>  	priv->can.do_get_berr_counter = rcar_can_get_berr_counter;
> 

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
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