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Message-ID: <cdc50fd9-fbc8-81b2-18b9-94be60eda375@linaro.org>
Date: Fri, 4 Aug 2023 10:46:12 +0200
From: Neil Armstrong <neil.armstrong@...aro.org>
To: Jerome Brunet <jbrunet@...libre.com>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Kevin Hilman <khilman@...libre.com>,
Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>,
Jagan Teki <jagan@...rulasolutions.com>,
Nicolas Belin <nbelin@...libre.com>
Cc: linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-amlogic@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org,
dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v7 3/9] clk: meson: add vclk driver
On 04/08/2023 09:33, Jerome Brunet wrote:
>
> On Thu 03 Aug 2023 at 14:03, Neil Armstrong <neil.armstrong@...aro.org> wrote:
>
>> The VCLK and VCLK_DIV clocks have supplementary bits.
>>
>> The VCLK 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.
>
> Unless there is reason, I'd prefer if this driver was using 'struct
> parm', like the rest of amlogic custom clock drivers, for consistency.
Ack
thx,
Neil
>
>>
>> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
>> ---
>> drivers/clk/meson/Kconfig | 5 ++
>> drivers/clk/meson/Makefile | 1 +
>> drivers/clk/meson/vclk.c | 146 +++++++++++++++++++++++++++++++++++++++++++++
>> drivers/clk/meson/vclk.h | 68 +++++++++++++++++++++
>> 4 files changed, 220 insertions(+)
>>
>> diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
>> index 135da8f2d0b1..83f629515e96 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
>>
>> @@ -140,6 +144,7 @@ config COMMON_CLK_G12A
>> select COMMON_CLK_MESON_EE_CLKC
>> select COMMON_CLK_MESON_CPU_DYNDIV
>> select COMMON_CLK_MESON_VID_PLL_DIV
>> + select COMMON_CLK_MESON_VCLK
>> select MFD_SYSCON
>> help
>> Support for the clock controller on Amlogic S905D2, S905X2 and S905Y2
>> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
>> index cd961cc4f4db..6efeb8c7bd2a 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..0df84403b17f
>> --- /dev/null
>> +++ b/drivers/clk/meson/vclk.c
>> @@ -0,0 +1,146 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2023 Neil Armstrong <neil.armstrong@...aro.org>
>> + */
>> +
>> +#include <linux/module.h>
>> +#include "vclk.h"
>> +
>> +/* The VCLK gate has a supplementary reset bit to pulse after ungating */
>> +
>> +static int clk_regmap_vclk_enable(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
>> +
>> + regmap_set_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
>> +
>> + /* Do a reset pulse */
>> + regmap_set_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
>> + regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
>> +
>> + return 0;
>> +}
>> +
>> +static void clk_regmap_vclk_disable(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
>> +
>> + regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
>> +}
>> +
>> +static int clk_regmap_vclk_is_enabled(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_data *vclk = clk_get_regmap_vclk_data(clk);
>> + unsigned int val;
>> +
>> + regmap_read(clk->map, vclk->offset, &val);
>> +
>> + return val & BIT(vclk->enable_bit_idx) ? 1 : 0;
>> +}
>> +
>> +const struct clk_ops clk_regmap_vclk_ops = {
>> + .enable = clk_regmap_vclk_enable,
>> + .disable = clk_regmap_vclk_disable,
>> + .is_enabled = clk_regmap_vclk_is_enabled,
>> +};
>> +EXPORT_SYMBOL_GPL(clk_regmap_vclk_ops);
>> +
>> +/* The VCLK Divider has supplementary reset & enable bits */
>> +
>> +static unsigned long clk_regmap_vclk_div_recalc_rate(struct clk_hw *hw,
>> + unsigned long prate)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> + unsigned int val;
>> + int ret;
>> +
>> + ret = regmap_read(clk->map, vclk->offset, &val);
>> + if (ret)
>> + /* Gives a hint that something is wrong */
>> + return 0;
>> +
>> + val >>= vclk->shift;
>> + val &= clk_div_mask(vclk->width);
>> +
>> + return divider_recalc_rate(hw, prate, val, vclk->table, vclk->flags,
>> + vclk->width);
>> +}
>> +
>> +static int clk_regmap_vclk_div_determine_rate(struct clk_hw *hw,
>> + struct clk_rate_request *req)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> +
>> + return divider_determine_rate(hw, req, vclk->table, vclk->width,
>> + vclk->flags);
>> +}
>> +
>> +static int clk_regmap_vclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
>> + unsigned long parent_rate)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> + unsigned int val;
>> + int ret;
>> +
>> + ret = divider_get_val(rate, parent_rate, vclk->table, vclk->width,
>> + vclk->flags);
>> + if (ret < 0)
>> + return ret;
>> +
>> + val = (unsigned int)ret << vclk->shift;
>> + return regmap_update_bits(clk->map, vclk->offset,
>> + clk_div_mask(vclk->width) << vclk->shift, val);
>> +};
>> +
>> +static int clk_regmap_vclk_div_enable(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> +
>> + /* Unreset the divider when ungating */
>> + regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
>> +
>> + return regmap_set_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
>> +}
>> +
>> +static void clk_regmap_vclk_div_disable(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> +
>> + /* Reset the divider when gating */
>> + regmap_clear_bits(clk->map, vclk->offset, BIT(vclk->enable_bit_idx));
>> +
>> + regmap_set_bits(clk->map, vclk->offset, BIT(vclk->reset_bit_idx));
>> +}
>> +
>> +static int clk_regmap_vclk_div_is_enabled(struct clk_hw *hw)
>> +{
>> + struct clk_regmap *clk = to_clk_regmap(hw);
>> + struct clk_regmap_vclk_div_data *vclk = clk_get_regmap_vclk_div_data(clk);
>> + unsigned int val;
>> +
>> + regmap_read(clk->map, vclk->offset, &val);
>> +
>> + return val & BIT(vclk->enable_bit_idx) ? 1 : 0;
>> +}
>> +
>> +const struct clk_ops clk_regmap_vclk_div_ops = {
>> + .recalc_rate = clk_regmap_vclk_div_recalc_rate,
>> + .determine_rate = clk_regmap_vclk_div_determine_rate,
>> + .set_rate = clk_regmap_vclk_div_set_rate,
>> + .enable = clk_regmap_vclk_div_enable,
>> + .disable = clk_regmap_vclk_div_disable,
>> + .is_enabled = clk_regmap_vclk_div_is_enabled,
>> +};
>> +EXPORT_SYMBOL_GPL(clk_regmap_vclk_div_ops);
>> +
>> +MODULE_DESCRIPTION("Amlogic vclk clock driver");
>> +MODULE_AUTHOR("Neil Armstrong <neil.armstrong@...aro.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..90786552a7f3
>> --- /dev/null
>> +++ b/drivers/clk/meson/vclk.h
>> @@ -0,0 +1,68 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (c) 2023 Neil Armstrong <neil.armstrong@...aro.org>
>> + */
>> +
>> +#ifndef __VCLK_H
>> +#define __VCLK_H
>> +
>> +#include "clk-regmap.h"
>> +
>> +/**
>> + * struct clk_regmap_vclk_data - vclk regmap backed specific data
>> + *
>> + * @offset: offset of the register controlling gate
>> + * @enable_bit_idx: single bit controlling vclk enable
>> + * @reset_bit_idx: single bit controlling vclk reset
>> + * @flags: hardware-specific flags
>> + *
>> + * Flags:
>> + * Same as clk_gate except CLK_GATE_HIWORD_MASK which is ignored
>> + */
>> +struct clk_regmap_vclk_data {
>> + unsigned int offset;
>> + u8 enable_bit_idx;
>> + u8 reset_bit_idx;
>> + u8 flags;
>> +};
>> +
>> +static inline struct clk_regmap_vclk_data *
>> +clk_get_regmap_vclk_data(struct clk_regmap *clk)
>> +{
>> + return (struct clk_regmap_vclk_data *)clk->data;
>> +}
>> +
>> +extern const struct clk_ops clk_regmap_vclk_ops;
>> +
>> +/**
>> + * struct clk_regmap_vclk_div_data - vclk_div regmap back specific data
>> + *
>> + * @offset: offset of the register controlling the divider
>> + * @shift: shift to the divider bit field
>> + * @width: width of the divider bit field
>> + * @enable_bit_idx: single bit controlling vclk divider enable
>> + * @reset_bit_idx: single bit controlling vclk divider reset
>> + * @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 clk_regmap_vclk_div_data {
>> + unsigned int offset;
>> + u8 shift;
>> + u8 width;
>> + u8 enable_bit_idx;
>> + u8 reset_bit_idx;
>> + const struct clk_div_table *table;
>> + u8 flags;
>> +};
>> +
>> +static inline struct clk_regmap_vclk_div_data *
>> +clk_get_regmap_vclk_div_data(struct clk_regmap *clk)
>> +{
>> + return (struct clk_regmap_vclk_div_data *)clk->data;
>> +}
>> +
>> +extern const struct clk_ops clk_regmap_vclk_div_ops;
>> +
>> +#endif /* __VCLK_H */
>
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