linux-kernel - Re: [PATCH 03/18] clk: meson: migrate a1 clock drivers out of hw_onecell_data to drop NR

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Message-ID: <20230609114847.x24by2foebojbchq@CAB-WSD-L081021>
Date:   Fri, 9 Jun 2023 14:48:47 +0300
From:   Dmitry Rokosov <ddrokosov@...rdevices.ru>
To:     Neil Armstrong <neil.armstrong@...aro.org>
CC:     Jerome Brunet <jbrunet@...libre.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Kevin Hilman <khilman@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        <linux-amlogic@...ts.infradead.org>, <linux-clk@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH 03/18] clk: meson: migrate a1 clock drivers out of
 hw_onecell_data to drop NR_CLKS

Hello Neil,

On Thu, Jun 08, 2023 at 02:53:50PM +0200, Neil Armstrong wrote:
> On 08/06/2023 14:45, Jerome Brunet wrote:
> > > +struct meson_a1_pll_clks {
> > > +	struct clk_hw **hw_clks;
> > > +	unsigned int hw_clk_num;
> > > +};
> > > +
> > > +static struct meson_a1_pll_clks a1_pll_clks = {
> > > +	.hw_clks = a1_pll_hw_clks,
> > > +	.hw_clk_num = ARRAY_SIZE(a1_pll_hw_clks),
> > > +};
> > > +
> > > +static struct clk_hw *meson_a1_pll_hw_get(struct of_phandle_args *clkspec, void *clk_data)
> > > +{
> > > +	const struct meson_a1_pll_clks *data = clk_data;
> > > +	unsigned int idx = clkspec->args[0];
> > > +
> > > +	if (idx >= data->hw_clk_num) {
> > > +		pr_err("%s: invalid index %u\n", __func__, idx);
> > > +		return ERR_PTR(-EINVAL);
> > > +	}
> > > +
> > > +	return data->hw_clks[idx];
> > > +}
> > 
> > I'd prefer to have a single struct type and and single custom
> > callback for the different SoC please.
> 
> Sure, I've written a common code for that, but I have a hard time finding
> a proper naming for it... so I choosed meson-clkc since it could have
> more common helper code for duplicated code over the clk driver:
> 
> ===================================><============================================================================
> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
> index 8ce846fdbe43..9070dcfd9e71 100644
> --- a/drivers/clk/meson/Kconfig
> +++ b/drivers/clk/meson/Kconfig
> @@ -30,6 +30,9 @@ config COMMON_CLK_MESON_VID_PLL_DIV
>  	tristate
>  	select COMMON_CLK_MESON_REGMAP
> 
> +config COMMON_CLK_MESON_CLKC
> +	tristate
> +
>  config COMMON_CLK_MESON_AO_CLKC
>  	tristate
>  	select COMMON_CLK_MESON_REGMAP
> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
> index d5288662881d..13c6db466986 100644
> --- a/drivers/clk/meson/Makefile
> +++ b/drivers/clk/meson/Makefile
> @@ -1,6 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  # Amlogic clock drivers
> 
> +obj-$(CONFIG_COMMON_CLK_MESON_CLKC) += meson-clkc.o
>  obj-$(CONFIG_COMMON_CLK_MESON_AO_CLKC) += meson-aoclk.o
>  obj-$(CONFIG_COMMON_CLK_MESON_CPU_DYNDIV) += clk-cpu-dyndiv.o
>  obj-$(CONFIG_COMMON_CLK_MESON_DUALDIV) += clk-dualdiv.o
> diff --git a/drivers/clk/meson/meson-clkc.c b/drivers/clk/meson/meson-clkc.c
> new file mode 100644
> index 000000000000..fa98b9d09011
> --- /dev/null
> +++ b/drivers/clk/meson/meson-clkc.c
> @@ -0,0 +1,25 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (c) 2023 Neil Armstrong <neil.armstrong@...aro.org>
> + */
> +
> +#include <linux/of_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/module.h>
> +#include "meson-clkc.h"
> +
> +struct clk_hw *meson_clk_hw_get(struct of_phandle_args *clkspec, void *clk_hw_data)
> +{
> +	const struct meson_clk_hw_data *data = clk_hw_data;
> +	unsigned int idx = clkspec->args[0];
> +
> +	if (idx >= data->num) {
> +		pr_err("%s: invalid index %u\n", __func__, idx);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	return data->hws[idx];
> +}
> +EXPORT_SYMBOL_GPL(meson_clk_hw_get);
> +
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/clk/meson/meson-clkc.h b/drivers/clk/meson/meson-clkc.h
> new file mode 100644
> index 000000000000..e3bad2aa17eb
> --- /dev/null
> +++ b/drivers/clk/meson/meson-clkc.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: (GPL-2.0+ OR MIT) */
> +/*
> + * Copyright (c) 2023 Neil Armstrong <neil.armstrong@...aro.org>
> + */
> +
> +#ifndef __MESON_HW_CLKC_H__
> +#define __MESON_HW_CLKC_H__
> +
> +#include <linux/of_device.h>
> +#include <linux/clk-provider.h>
> +
> +struct meson_clk_hw_data {
> +	struct clk_hw	**hws;
> +	unsigned int	num;
> +};
> +
> +struct clk_hw *meson_clk_hw_get(struct of_phandle_args *clkspec, void *clk_hw_data);
> +
> +#endif
> ===================================><============================================================================
> 
> If it's ok I'll send a v2 using this.
> 
> Thanks,
> Neil

In addition, I propose consolidating the probe() routine of the a1
clocks into a common part, which can be utilized for s4 and other
similar clocks. This solution was presented in the early a1 review
stages of this patch set.

https://lore.kernel.org/linux-amlogic/20221201225703.6507-7-ddrokosov@sberdevices.ru/

Maybe, it can be generalized for the all meson clock controller drivers.

-- 
Thank you,
Dmitry