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: <04791890-56f3-e620-1660-e8ed80eb5752@linaro.org>
Date:   Fri, 9 Jun 2023 14:47:04 +0200
From:   Neil Armstrong <neil.armstrong@...aro.org>
To:     Dmitry Rokosov <ddrokosov@...rdevices.ru>
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

Hi,

On 09/06/2023 13:48, Dmitry Rokosov wrote:
> 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.
> 

Sure, the goal of that is to get rid of NR_CLKS & private IDS only,
then yes afterwards any common clkc function will be welcome !

Neil