Re: [PATCH 4/4] can: bxcan: add support for single peripheral configuration - Marc Kleine-Budde

From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Cc: linux-kernel@vger.kernel.org,
	Amarula patchwork <linux-amarula@amarulasolutions.com>,
	michael@amarulasolutions.com,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Wolfgang Grandegger <wg@grandegger.com>,
	linux-can@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH 4/4] can: bxcan: add support for single peripheral configuration
Date: Sun, 23 Apr 2023 21:16:54 +0200	[thread overview]
Message-ID: <20230423-surplus-spoon-4e8194434663-mkl@pengutronix.de> (raw)
In-Reply-To: <20230423172528.1398158-5-dario.binacchi@amarulasolutions.com>

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On 23.04.2023 19:25:28, Dario Binacchi wrote:
> Add support for bxCAN controller in single peripheral configuration:
> - primary bxCAN
> - dedicated Memory Access Controller unit
> - 512-byte SRAM memory
> - 14 fiter banks
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> 
> ---
> 
>  drivers/net/can/bxcan.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/can/bxcan.c b/drivers/net/can/bxcan.c
> index e26ccd41e3cb..9bcbbb85da6e 100644
> --- a/drivers/net/can/bxcan.c
> +++ b/drivers/net/can/bxcan.c
> @@ -155,6 +155,7 @@ struct bxcan_regs {
>  	u32 reserved0[88];		/* 0x20 */
>  	struct bxcan_mb tx_mb[BXCAN_TX_MB_NUM];	/* 0x180 - tx mailbox */
>  	struct bxcan_mb rx_mb[BXCAN_RX_MB_NUM];	/* 0x1b0 - rx mailbox */
> +	u32 reserved1[12];		/* 0x1d0 */
>  };
>  
>  struct bxcan_priv {
> @@ -922,6 +923,12 @@ static int bxcan_get_berr_counter(const struct net_device *ndev,
>  	return 0;
>  }
>  
> +static const struct regmap_config bxcan_gcan_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
>  static int bxcan_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> @@ -942,11 +949,18 @@ static int bxcan_probe(struct platform_device *pdev)
>  
>  	gcan = syscon_regmap_lookup_by_phandle(np, "st,gcan");
>  	if (IS_ERR(gcan)) {
> -		dev_err(dev, "failed to get shared memory base address\n");
> -		return PTR_ERR(gcan);
> +		primary = true;
> +		gcan = devm_regmap_init_mmio(dev,
> +					     regs + sizeof(struct bxcan_regs),
> +					     &bxcan_gcan_regmap_config);
> +		if (IS_ERR(gcan)) {
> +			dev_err(dev, "failed to get filter base address\n");
> +			return PTR_ERR(gcan);
> +		}

This probably works. Can we do better, i.e. without this additional code?

If you add a syscon node for the single instance CAN, too, you don't
need a code change here, right?

> +	} else {
> +		primary = of_property_read_bool(np, "st,can-primary");
>  	}
>  
> -	primary = of_property_read_bool(np, "st,can-primary");
>  	clk = devm_clk_get(dev, NULL);
>  	if (IS_ERR(clk)) {
>  		dev_err(dev, "failed to get clock\n");

Marc

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