From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38CFBC433EF for ; Tue, 11 Jan 2022 16:24:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242322AbiAKQYa (ORCPT ); Tue, 11 Jan 2022 11:24:30 -0500 Received: from foss.arm.com ([217.140.110.172]:49066 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241083AbiAKQY1 (ORCPT ); Tue, 11 Jan 2022 11:24:27 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 879AD6D; Tue, 11 Jan 2022 08:24:26 -0800 (PST) Received: from donnerap.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F31BB3F774; Tue, 11 Jan 2022 08:24:24 -0800 (PST) Date: Tue, 11 Jan 2022 16:24:22 +0000 From: Andre Przywara To: Evgeny Boger Cc: Maxime Ripard , Chen-Yu Tsai , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-sunxi@lists.linux.dev, linux-can@vger.kernel.org, Wolfgang Grandegger , Marc Kleine-Budde , "David S . Miller" , Jeroen Hofstee , Gerhard Bertelsmann Subject: Re: [PATCH v2 2/3] can: sun4i_can: add support for R40 CAN controller Message-ID: <20220111162422.62d0ceb0@donnerap.cambridge.arm.com> In-Reply-To: <20220111155709.56501-3-boger@wirenboard.com> References: <20220111155709.56501-1-boger@wirenboard.com> <20220111155709.56501-3-boger@wirenboard.com> Organization: ARM X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; aarch64-unknown-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On Tue, 11 Jan 2022 18:57:08 +0300 Evgeny Boger wrote: Hi, > Allwinner R40 (also known as A40i, T3, V40) has a CAN controller. The > controller is the same as in earlier A10 and A20 SoCs, but needs reset > line to be deasserted before use. > > This patch adds a new compatible for R40 CAN controller. Depending > on the compatible, reset line can be requested from DT. > > Signed-off-by: Evgeny Boger > --- > drivers/net/can/sun4i_can.c | 61 ++++++++++++++++++++++++++++++++++++- > 1 file changed, 60 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/can/sun4i_can.c b/drivers/net/can/sun4i_can.c > index 54aa7c25c4de..24a61326915e 100644 > --- a/drivers/net/can/sun4i_can.c > +++ b/drivers/net/can/sun4i_can.c > @@ -61,6 +61,7 @@ > #include > #include > #include > +#include > > #define DRV_NAME "sun4i_can" > > @@ -200,10 +201,20 @@ > #define SUN4I_CAN_MAX_IRQ 20 > #define SUN4I_MODE_MAX_RETRIES 100 > > +/** > + * struct sun4ican_quirks - Differences between SoC variants. > + * > + * @has_reset: SoC needs reset deasserted. > + */ > +struct sun4ican_quirks { > + bool has_reset; > +}; > + > struct sun4ican_priv { > struct can_priv can; > void __iomem *base; > struct clk *clk; > + struct reset_control *reset; > spinlock_t cmdreg_lock; /* lock for concurrent cmd register writes */ > }; > > @@ -702,6 +713,13 @@ static int sun4ican_open(struct net_device *dev) > goto exit_irq; > } > > + /* software reset deassert */ > + err = reset_control_deassert(priv->reset); > + if (err) { > + netdev_err(dev, "could not deassert CAN reset\n"); > + goto exit_soft_reset; > + } > + > /* turn on clocking for CAN peripheral block */ > err = clk_prepare_enable(priv->clk); > if (err) { > @@ -723,6 +741,8 @@ static int sun4ican_open(struct net_device *dev) > exit_can_start: > clk_disable_unprepare(priv->clk); > exit_clock: > + reset_control_assert(priv->reset); > +exit_soft_reset: > free_irq(dev->irq, dev); > exit_irq: > close_candev(dev); > @@ -736,6 +756,7 @@ static int sun4ican_close(struct net_device *dev) > netif_stop_queue(dev); > sun4i_can_stop(dev); > clk_disable_unprepare(priv->clk); > + reset_control_assert(priv->reset); > > free_irq(dev->irq, dev); > close_candev(dev); > @@ -750,8 +771,27 @@ static const struct net_device_ops sun4ican_netdev_ops = { > .ndo_start_xmit = sun4ican_start_xmit, > }; > > +static const struct sun4ican_quirks sun4ican_quirks_a10 = { > + .has_reset = false, > +}; > + > +static const struct sun4ican_quirks sun4ican_quirks_r40 = { > + .has_reset = true, > +}; > + > static const struct of_device_id sun4ican_of_match[] = { > - {.compatible = "allwinner,sun4i-a10-can"}, > + { > + .compatible = "allwinner,sun4i-a10-can", > + .data = &sun4ican_quirks_a10 > + }, > + { > + .compatible = "allwinner,sun7i-a20-can", > + .data = &sun4ican_quirks_a10 > + }, This one looks unnecessary, the binding says that it must be paired with the A10 fallback. We should only add an A20 compatible match if there is really a reason, otherwise it encourages people to produce DTs with *only* the A20 compatible (violating the binding). Cheers, Andre > + { > + .compatible = "allwinner,sun8i-r40-can", > + .data = &sun4ican_quirks_r40 > + }, > {}, > }; > > @@ -771,10 +811,28 @@ static int sun4ican_probe(struct platform_device *pdev) > { > struct device_node *np = pdev->dev.of_node; > struct clk *clk; > + struct reset_control *reset = NULL; > void __iomem *addr; > int err, irq; > struct net_device *dev; > struct sun4ican_priv *priv; > + const struct sun4ican_quirks *quirks; > + > + quirks = of_device_get_match_data(&pdev->dev); > + if (!quirks) { > + dev_err(&pdev->dev, "failed to determine the quirks to use\n"); > + err = -ENODEV; > + goto exit; > + } > + > + if (quirks->has_reset) { > + reset = devm_reset_control_get_exclusive(&pdev->dev, NULL); > + if (IS_ERR(reset)) { > + dev_err(&pdev->dev, "unable to request reset\n"); > + err = PTR_ERR(reset); > + goto exit; > + } > + } > > clk = of_clk_get(np, 0); > if (IS_ERR(clk)) { > @@ -818,6 +876,7 @@ static int sun4ican_probe(struct platform_device *pdev) > CAN_CTRLMODE_3_SAMPLES; > priv->base = addr; > priv->clk = clk; > + priv->reset = reset; > spin_lock_init(&priv->cmdreg_lock); > > platform_set_drvdata(pdev, dev);