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Message-ID: <2cf79f07-0ae1-4267-ac08-fe40366d87d4@linaro.org>
Date: Thu, 4 Apr 2024 18:59:51 +0200
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From: Neil Armstrong <neil.armstrong@linaro.org>
Reply-To: neil.armstrong@linaro.org
Subject: Re: [PATCH v12 2/7] clk: meson: add vclk driver
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Rob Herring <robh@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>,
 Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
 Kevin Hilman <khilman@baylibre.com>,
 Michael Turquette <mturquette@baylibre.com>, Stephen Boyd
 <sboyd@kernel.org>, Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
 Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>,
 David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>,
 Jagan Teki <jagan@amarulasolutions.com>, Nicolas Belin
 <nbelin@baylibre.com>, devicetree@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org,
 linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
 dri-devel@lists.freedesktop.org
References: <20240403-amlogic-v6-4-upstream-dsi-ccf-vim3-v12-0-99ecdfdc87fc@linaro.org>
 <20240403-amlogic-v6-4-upstream-dsi-ccf-vim3-v12-2-99ecdfdc87fc@linaro.org>
 <1jmsq9pmgd.fsf@starbuckisacylon.baylibre.com>
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In-Reply-To: <1jmsq9pmgd.fsf@starbuckisacylon.baylibre.com>
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On 04/04/2024 10:13, Jerome Brunet wrote:
> 
> On Wed 03 Apr 2024 at 09:46, Neil Armstrong <neil.armstrong@linaro.org> wrote:
> 
>> The VCLK and VCLK_DIV clocks have supplementary bits.
>>
>> The VCLK gate has a "SOFT RESET" bit to toggle after the whole
>> VCLK sub-tree rate has been set, this is implemented in
>> the gate enable callback.
>>
>> The VCLK_DIV clocks as enable and reset bits used to disable
>> and reset the divider, associated with CLK_SET_RATE_GATE it ensures
>> the rate is set while the divider is disabled and in reset mode.
>>
>> The VCLK_DIV enable bit isn't implemented as a gate since it's part
>> of the divider logic and vendor does this exact sequence to ensure
>> the divider is correctly set.
> 
> The checkpatch warning is still there. Is it a choice or a mistake ?
> 
> Documentation says "GPL v2" exists for historic reason which seems to
> hint "GPL" is preferred, and I suppose this is why checkpatch warns for
> it.

Well I didn't see this warning, this is what I fixed:

$ scripts/checkpatch.pl --strict drivers/clk/meson/vclk.c
CHECK: Alignment should match open parenthesis
#63: FILE: drivers/clk/meson/vclk.c:63:
+static unsigned long meson_vclk_div_recalc_rate(struct clk_hw *hw,
+                                                    unsigned long prate)

CHECK: Alignment should match open parenthesis
#73: FILE: drivers/clk/meson/vclk.c:73:
+static int meson_vclk_div_determine_rate(struct clk_hw *hw,
+                                             struct clk_rate_request *req)

CHECK: Alignment should match open parenthesis
#83: FILE: drivers/clk/meson/vclk.c:83:
+static int meson_vclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
+                                       unsigned long parent_rate)

<snip>

It seems that checking a commit triggers an extra check....

$ scripts/checkpatch.pl --strict -G 1bac9f6aa3c3
WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
#58:
new file mode 100644

<snip>

WARNING: Prefer "GPL" over "GPL v2" - see commit bf7fbeeae6db ("module: Cure the MODULE_LICENSE "GPL" vs. "GPL v2" bogosity")
#203: FILE: drivers/clk/meson/vclk.c:141:
+MODULE_LICENSE("GPL v2");

<snip>

Neil

> 
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
>> ---
>>   drivers/clk/meson/Kconfig  |   4 ++
>>   drivers/clk/meson/Makefile |   1 +
>>   drivers/clk/meson/vclk.c   | 141 +++++++++++++++++++++++++++++++++++++++++++++
>>   drivers/clk/meson/vclk.h   |  51 ++++++++++++++++
>>   4 files changed, 197 insertions(+)
>>
>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>> index 29ffd14d267b..8a9823789fa3 100644
>> --- a/drivers/clk/meson/Kconfig
>> +++ b/drivers/clk/meson/Kconfig
>> @@ -30,6 +30,10 @@ config COMMON_CLK_MESON_VID_PLL_DIV
>>   	tristate
>>   	select COMMON_CLK_MESON_REGMAP
>>   
>> +config COMMON_CLK_MESON_VCLK
>> +	tristate
>> +	select COMMON_CLK_MESON_REGMAP
>> +
>>   config COMMON_CLK_MESON_CLKC_UTILS
>>   	tristate
>>   
>> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
>> index 9ee4b954c896..9ba43fe7a07a 100644
>> --- a/drivers/clk/meson/Makefile
>> +++ b/drivers/clk/meson/Makefile
>> @@ -12,6 +12,7 @@ obj-$(CONFIG_COMMON_CLK_MESON_PLL) += clk-pll.o
>>   obj-$(CONFIG_COMMON_CLK_MESON_REGMAP) += clk-regmap.o
>>   obj-$(CONFIG_COMMON_CLK_MESON_SCLK_DIV) += sclk-div.o
>>   obj-$(CONFIG_COMMON_CLK_MESON_VID_PLL_DIV) += vid-pll-div.o
>> +obj-$(CONFIG_COMMON_CLK_MESON_VCLK) += vclk.o
>>   
>>   # Amlogic Clock controllers
>>   
>> diff --git a/drivers/clk/meson/vclk.c b/drivers/clk/meson/vclk.c
>> new file mode 100644
>> index 000000000000..45dc216941ea
>> --- /dev/null
>> +++ b/drivers/clk/meson/vclk.c
>> @@ -0,0 +1,141 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2024 Neil Armstrong <neil.armstrong@linaro.org>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include "vclk.h"
>> +
>> +/* The VCLK gate has a supplementary reset bit to pulse after ungating */
>> +
>> +static inline struct meson_vclk_gate_data *
>> +clk_get_meson_vclk_gate_data(struct clk_regmap *clk)
>> +{
>> +	return (struct meson_vclk_gate_data *)clk->data;
>> +}
>> +
>> +static int meson_vclk_gate_enable(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_gate_data *vclk = clk_get_meson_vclk_gate_data(clk);
>> +
>> +	meson_parm_write(clk->map, &vclk->enable, 1);
>> +
>> +	/* Do a reset pulse */
>> +	meson_parm_write(clk->map, &vclk->reset, 1);
>> +	meson_parm_write(clk->map, &vclk->reset, 0);
>> +
>> +	return 0;
>> +}
>> +
>> +static void meson_vclk_gate_disable(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_gate_data *vclk = clk_get_meson_vclk_gate_data(clk);
>> +
>> +	meson_parm_write(clk->map, &vclk->enable, 0);
>> +}
>> +
>> +static int meson_vclk_gate_is_enabled(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_gate_data *vclk = clk_get_meson_vclk_gate_data(clk);
>> +
>> +	return meson_parm_read(clk->map, &vclk->enable);
>> +}
>> +
>> +const struct clk_ops meson_vclk_gate_ops = {
>> +	.enable = meson_vclk_gate_enable,
>> +	.disable = meson_vclk_gate_disable,
>> +	.is_enabled = meson_vclk_gate_is_enabled,
>> +};
>> +EXPORT_SYMBOL_GPL(meson_vclk_gate_ops);
>> +
>> +/* The VCLK Divider has supplementary reset & enable bits */
>> +
>> +static inline struct meson_vclk_div_data *
>> +clk_get_meson_vclk_div_data(struct clk_regmap *clk)
>> +{
>> +	return (struct meson_vclk_div_data *)clk->data;
>> +}
>> +
>> +static unsigned long meson_vclk_div_recalc_rate(struct clk_hw *hw,
>> +						unsigned long prate)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +
>> +	return divider_recalc_rate(hw, prate, meson_parm_read(clk->map, &vclk->div),
>> +				   vclk->table, vclk->flags, vclk->div.width);
>> +}
>> +
>> +static int meson_vclk_div_determine_rate(struct clk_hw *hw,
>> +					 struct clk_rate_request *req)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +
>> +	return divider_determine_rate(hw, req, vclk->table, vclk->div.width,
>> +				      vclk->flags);
>> +}
>> +
>> +static int meson_vclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
>> +				   unsigned long parent_rate)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +	int ret;
>> +
>> +	ret = divider_get_val(rate, parent_rate, vclk->table, vclk->div.width,
>> +			      vclk->flags);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	meson_parm_write(clk->map, &vclk->div, ret);
>> +
>> +	return 0;
>> +};
>> +
>> +static int meson_vclk_div_enable(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +
>> +	/* Unreset the divider when ungating */
>> +	meson_parm_write(clk->map, &vclk->reset, 0);
>> +	meson_parm_write(clk->map, &vclk->enable, 1);
>> +
>> +	return 0;
>> +}
>> +
>> +static void meson_vclk_div_disable(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +
>> +	/* Reset the divider when gating */
>> +	meson_parm_write(clk->map, &vclk->enable, 0);
>> +	meson_parm_write(clk->map, &vclk->reset, 1);
>> +}
>> +
>> +static int meson_vclk_div_is_enabled(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap *clk = to_clk_regmap(hw);
>> +	struct meson_vclk_div_data *vclk = clk_get_meson_vclk_div_data(clk);
>> +
>> +	return meson_parm_read(clk->map, &vclk->enable);
>> +}
>> +
>> +const struct clk_ops meson_vclk_div_ops = {
>> +	.recalc_rate = meson_vclk_div_recalc_rate,
>> +	.determine_rate = meson_vclk_div_determine_rate,
>> +	.set_rate = meson_vclk_div_set_rate,
>> +	.enable = meson_vclk_div_enable,
>> +	.disable = meson_vclk_div_disable,
>> +	.is_enabled = meson_vclk_div_is_enabled,
>> +};
>> +EXPORT_SYMBOL_GPL(meson_vclk_div_ops);
>> +
>> +MODULE_DESCRIPTION("Amlogic vclk clock driver");
>> +MODULE_AUTHOR("Neil Armstrong <neil.armstrong@linaro.org>");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/clk/meson/vclk.h b/drivers/clk/meson/vclk.h
>> new file mode 100644
>> index 000000000000..20b0b181db09
>> --- /dev/null
>> +++ b/drivers/clk/meson/vclk.h
>> @@ -0,0 +1,51 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2024 Neil Armstrong <neil.armstrong@linaro.org>
>> + */
>> +
>> +#ifndef __VCLK_H
>> +#define __VCLK_H
>> +
>> +#include "clk-regmap.h"
>> +#include "parm.h"
>> +
>> +/**
>> + * struct meson_vclk_gate_data - vclk_gate regmap backed specific data
>> + *
>> + * @enable:	vclk enable field
>> + * @reset:	vclk reset field
>> + * @flags:	hardware-specific flags
>> + *
>> + * Flags:
>> + * Same as clk_gate except CLK_GATE_HIWORD_MASK which is ignored
>> + */
>> +struct meson_vclk_gate_data {
>> +	struct parm enable;
>> +	struct parm reset;
>> +	u8 flags;
>> +};
>> +
>> +extern const struct clk_ops meson_vclk_gate_ops;
>> +
>> +/**
>> + * struct meson_vclk_div_data - vclk_div regmap back specific data
>> + *
>> + * @div:	divider field
>> + * @enable:	vclk divider enable field
>> + * @reset:	vclk divider reset field
>> + * @table:	array of value/divider pairs, last entry should have div = 0
>> + *
>> + * Flags:
>> + * Same as clk_divider except CLK_DIVIDER_HIWORD_MASK which is ignored
>> + */
>> +struct meson_vclk_div_data {
>> +	struct parm div;
>> +	struct parm enable;
>> +	struct parm reset;
>> +	const struct clk_div_table *table;
>> +	u8 flags;
>> +};
>> +
>> +extern const struct clk_ops meson_vclk_div_ops;
>> +
>> +#endif /* __VCLK_H */
> 
>