linux-kernel - Re: [PATCH 27/89] clk: bcm: Add BCM2711 DVP driver

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Message-ID: <158406125965.149997.13919203635322854760@swboyd.mtv.corp.google.com>
Date:   Thu, 12 Mar 2020 18:00:59 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Eric Anholt <eric@...olt.net>, Maxime Ripard <maxime@...no.tech>,
        Nicolas Saenz Julienne <nsaenzjulienne@...e.de>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-rpi-kernel@...ts.infradead.org,
        bcm-kernel-feedback-list@...adcom.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Tim Gover <tim.gover@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Maxime Ripard <maxime@...no.tech>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Herring <robh+dt@...nel.org>, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 27/89] clk: bcm: Add BCM2711 DVP driver

Quoting Maxime Ripard (2020-02-24 01:06:29)
> diff --git a/drivers/clk/bcm/clk-bcm2711-dvp.c b/drivers/clk/bcm/clk-bcm2711-dvp.c
> new file mode 100644
> index 000000000000..f4773cc92724
> --- /dev/null
> +++ b/drivers/clk/bcm/clk-bcm2711-dvp.c
> @@ -0,0 +1,113 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// Copyright 2020 Cerno
> +
> +#include <linux/clk-provider.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset-controller.h>
> +#include <linux/reset/reset-simple.h>
> +
> +#define DVP_HT_RPI_SW_INIT     0x04
> +#define DVP_HT_RPI_MISC_CONFIG 0x08
> +
> +#define NR_CLOCKS      2
> +#define NR_RESETS      6
> +
> +struct clk_dvp {
> +       struct clk                      *clks[NR_CLOCKS];
> +       struct clk_onecell_data         clk_data;
> +       struct reset_simple_data        reset;
> +};
> +
> +static int clk_dvp_probe(struct platform_device *pdev)
> +{
> +       struct resource *res;
> +       struct clk_dvp *dvp;
> +       void __iomem *base;
> +       const char *parent;
> +       int ret;
> +
> +       dvp = devm_kzalloc(&pdev->dev, sizeof(*dvp), GFP_KERNEL);
> +       if (!dvp)
> +               return -ENOMEM;
> +       platform_set_drvdata(pdev, dvp);
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       base = devm_ioremap_resource(&pdev->dev, res);
> +       if (IS_ERR(base))
> +               return PTR_ERR(base);
> +
> +       dvp->reset.rcdev.owner = THIS_MODULE;
> +       dvp->reset.rcdev.nr_resets = NR_RESETS;
> +       dvp->reset.rcdev.ops = &reset_simple_ops;
> +       dvp->reset.rcdev.of_node = pdev->dev.of_node;
> +       dvp->reset.membase = base + DVP_HT_RPI_SW_INIT;
> +       spin_lock_init(&dvp->reset.lock);
> +
> +       ret = reset_controller_register(&dvp->reset.rcdev);
> +       if (ret)
> +               return ret;
> +
> +       parent = of_clk_get_parent_name(pdev->dev.of_node, 0);
> +       if (!parent)
> +               goto unregister_reset;
> +
> +       dvp->clks[0] = clk_register_gate(&pdev->dev, "hdmi0-108MHz",
> +                                        parent, CLK_IS_CRITICAL,
> +                                        base + DVP_HT_RPI_MISC_CONFIG, 3,
> +                                        CLK_GATE_SET_TO_DISABLE, &dvp->reset.lock);
> +       if (IS_ERR(dvp->clks[0])) {
> +               ret = PTR_ERR(dvp->clks[0]);
> +               goto unregister_reset;
> +       }
> +
> +       dvp->clks[1] = clk_register_gate(&pdev->dev, "hdmi1-108MHz",
> +                                        parent, CLK_IS_CRITICAL,
> +                                        base + DVP_HT_RPI_MISC_CONFIG, 4,
> +                                        CLK_GATE_SET_TO_DISABLE, &dvp->reset.lock);

Can we use clk_hw APIs, document why CLK_IS_CRITICAL, and use something
like clk_hw_register_gate_parent_data() so that we don't have to use
of_clk_get_parent_name() above?


> +       if (IS_ERR(dvp->clks[1])) {
> +               ret = PTR_ERR(dvp->clks[1]);
> +               goto unregister_clk0;
> +       }
> +
> +       dvp->clk_data.clks = dvp->clks;
> +       dvp->clk_data.clk_num = NR_CLOCKS;
> +       of_clk_add_provider(pdev->dev.of_node, of_clk_src_onecell_get,
> +                           &dvp->clk_data);

This can fail. Please recover. Also, please use clk_hw based APIs.

> +
> +       return 0;
> +
> +
> +unregister_clk0:
> +       clk_unregister_gate(dvp->clks[0]);
> +
> +unregister_reset:
> +       reset_controller_unregister(&dvp->reset.rcdev);
> +       return ret;
> +};
> +
> +static int clk_dvp_remove(struct platform_device *pdev)
> +{
> +       struct clk_dvp *dvp = platform_get_drvdata(pdev);
> +
> +       clk_unregister_gate(dvp->clks[1]);
> +       clk_unregister_gate(dvp->clks[0]);
> +       reset_controller_unregister(&dvp->reset.rcdev);
> +
> +       return 0;
> +}
> +
> +static const struct of_device_id clk_dvp_dt_ids[] = {
> +       { .compatible = "brcm,brcm2711-dvp", },
> +       { /* sentinel */ },

Please drop comma after this so we can't put anything after lest it
cause a compiler error.

> +};
> +
> +static struct platform_driver clk_dvp_driver = {
> +       .probe  = clk_dvp_probe,
> +       .remove = clk_dvp_remove,
> +       .driver = {
> +               .name           = "brcm2711-dvp",
> +               .of_match_table = clk_dvp_dt_ids,
> +       },
> +};
> +module_platform_driver(clk_dvp_driver);
> -- 
> git-series 0.9.1