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Date: Thu, 20 Sep 2018 17:01:56 -0700
From: Andrey Smirnov <andrew.smirnov@...il.com>
To: Abel Vesa <abel.vesa@....com>
Cc: Lucas Stach <l.stach@...gutronix.de>,
Sascha Hauer <kernel@...gutronix.de>,
Dong Aisheng <aisheng.dong@....com>,
Fabio Estevam <fabio.estevam@....com>,
Anson Huang <anson.huang@....com>,
Rob Herring <robh@...nel.org>, linux-imx@....com,
abelvesa@...ux.com, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Michael Turquette <mturquette@...libre.com>, sboyd@...nel.org,
linux-kernel <linux-kernel@...r.kernel.org>,
linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
linux-clk@...r.kernel.org
Subject: Re: [PATCH v7 4/5] clk: imx: add imx composite clock
On Thu, Sep 20, 2018 at 3:07 AM Abel Vesa <abel.vesa@....com> wrote:
>
> Since a lot of clocks on imx8 are formed by a mux, gate, predivider and
> divider, the idea here is to combine all of those into one composite clock,
> but we need to deal with both predivider and divider at the same time and
> therefore we add the imx_clk_composite_divider_ops and register the composite
> clock with those.
>
> Signed-off-by: Abel Vesa <abel.vesa@....com>
> Suggested-by: Sascha Hauer <s.hauer@...gutronix.de>
> ---
> drivers/clk/imx/Makefile | 1 +
> drivers/clk/imx/clk-composite.c | 155 ++++++++++++++++++++++++++++++++++++++++
> drivers/clk/imx/clk.h | 11 +++
> 3 files changed, 167 insertions(+)
> create mode 100644 drivers/clk/imx/clk-composite.c
>
> diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
> index b87513c..4fabb0a 100644
> --- a/drivers/clk/imx/Makefile
> +++ b/drivers/clk/imx/Makefile
> @@ -3,6 +3,7 @@
> obj-y += \
> clk.o \
> clk-busy.o \
> + clk-composite.o \
> clk-cpu.o \
> clk-fixup-div.o \
> clk-fixup-mux.o \
> diff --git a/drivers/clk/imx/clk-composite.c b/drivers/clk/imx/clk-composite.c
> new file mode 100644
> index 0000000..40c2aa8
> --- /dev/null
> +++ b/drivers/clk/imx/clk-composite.c
> @@ -0,0 +1,155 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2018 NXP
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/slab.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>
> +
> +#include "clk.h"
> +
> +#define PCG_PREDIV_SHIFT 16
> +#define PCG_PREDIV_WIDTH 3
> +
> +#define PCG_DIV_SHIFT 0
> +#define PCG_DIV_WIDTH 6
> +
> +#define PCG_PCS_SHIFT 24
> +#define PCG_PCS_MASK 0x7
> +
> +#define PCG_CGC_SHIFT 28
> +
> +static unsigned long imx_clk_composite_divider_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct clk_divider *divider = to_clk_divider(hw);
> + unsigned long prediv_rate;
> + unsigned int prediv_value;
> + unsigned int div_value;
> +
> + prediv_value = clk_readl(divider->reg) >> divider->shift;
> + prediv_value &= clk_div_mask(divider->width);
> +
> + prediv_rate = divider_recalc_rate(hw, parent_rate, prediv_value,
> + NULL, divider->flags,
> + divider->width);
> +
> + div_value = clk_readl(divider->reg) >> PCG_DIV_SHIFT;
> + div_value &= clk_div_mask(PCG_DIV_WIDTH);
> +
> + return divider_recalc_rate(hw, prediv_rate, div_value, NULL,
> + divider->flags, PCG_DIV_WIDTH);
> +}
> +
> +static long imx_clk_composite_divider_round_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long *prate)
> +{
> + struct clk_divider *divider = to_clk_divider(hw);
> + unsigned long prediv_rate;
> +
> + prediv_rate = divider_round_rate(hw, rate, prate, divider->table,
> + divider->width, divider->flags);
> + return divider_round_rate(hw, rate, &prediv_rate, divider->table,
> + PCG_DIV_WIDTH, divider->flags);
> +}
> +
> +static int imx_clk_composite_divider_set_rate(struct clk_hw *hw,
> + unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct clk_divider *divider = to_clk_divider(hw);
> + unsigned long prediv_rate;
> + unsigned long flags = 0;
> + int prediv_value;
> + int div_value;
> + u32 val;
> +
> + prediv_value = divider_get_val(rate, parent_rate, NULL,
> + PCG_PREDIV_WIDTH, CLK_DIVIDER_ROUND_CLOSEST);
> + if (prediv_value < 0)
> + return prediv_value;
> +
> + prediv_rate = DIV_ROUND_UP_ULL((u64)parent_rate, prediv_value + 1);
> +
> + div_value = divider_get_val(rate, prediv_rate, NULL,
> + PCG_DIV_WIDTH, CLK_DIVIDER_ROUND_CLOSEST);
> + if (div_value < 0)
> + return div_value;
> +
> + spin_lock_irqsave(divider->lock, flags);
> +
> + val = clk_readl(divider->reg);
> + val &= ~((clk_div_mask(divider->width) << divider->shift) |
> + (clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
> +
> + val |= (u32)prediv_value << divider->shift;
> + val |= (u32)div_value << PCG_DIV_SHIFT;
> + clk_writel(val, divider->reg);
> +
> + spin_unlock_irqrestore(divider->lock, flags);
> +
> + return 0;
> +}
> +
> +static const struct clk_ops imx_clk_composite_divider_ops = {
> + .recalc_rate = imx_clk_composite_divider_recalc_rate,
> + .round_rate = imx_clk_composite_divider_round_rate,
> + .set_rate = imx_clk_composite_divider_set_rate,
> +};
> +
> +struct clk *imx_clk_composite_flags(const char *name,
> + const char **parent_names,
> + int num_parents, void __iomem *reg,
> + unsigned long flags)
> +{
> + struct clk_hw *mux_hw = NULL, *div_hw = NULL, *gate_hw = NULL;
> + struct clk_divider *div = NULL;
> + struct clk_gate *gate = NULL;
> + struct clk_mux *mux = NULL;
> + struct clk *clk;
> +
> + mux = kzalloc(sizeof(*mux), GFP_KERNEL);
> + if (!mux)
> + return ERR_PTR(-ENOMEM);
> + mux_hw = &mux->hw;
> + mux->reg = reg;
> + mux->shift = PCG_PCS_SHIFT;
> + mux->mask = PCG_PCS_MASK;
> +
> + div = kzalloc(sizeof(*div), GFP_KERNEL);
> + if (!div) {
> + kfree(mux);
> + return ERR_PTR(-ENOMEM);
> + }
> + div_hw = &div->hw;
> + div->reg = reg;
> + div->shift = PCG_PREDIV_SHIFT;
> + div->width = PCG_PREDIV_WIDTH;
> + div->lock = &imx_ccm_lock;
> + div->flags = CLK_DIVIDER_ROUND_CLOSEST;
> +
> + gate = kzalloc(sizeof(*gate), GFP_KERNEL);
> + if (!gate) {
> + kfree(mux);
> + kfree(div);
> + return ERR_PTR(-ENOMEM);
> + }
> + gate_hw = &gate->hw;
> + gate->reg = reg;
> + gate->bit_idx = PCG_CGC_SHIFT;
> +
> + clk = clk_register_composite(NULL, name, parent_names, num_parents,
> + mux_hw, &clk_mux_ops, div_hw,
> + &imx_clk_composite_divider_ops, gate_hw,
> + &clk_gate_ops, flags);
> + if (IS_ERR(clk)) {
> + kfree(mux);
> + kfree(div);
> + kfree(gate);
Minor suggestion: using goto to free resource in this case might be
more straightforward and require less repeatition.
> + }
> +
> + return clk;
> +}
> diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
> index 12b3fd6..74d8d46 100644
> --- a/drivers/clk/imx/clk.h
> +++ b/drivers/clk/imx/clk.h
> @@ -232,4 +232,15 @@ struct clk *imx_clk_cpu(const char *name, const char *parent_name,
> struct clk *div, struct clk *mux, struct clk *pll,
> struct clk *step);
>
> +struct clk *imx_clk_composite_flags(const char *name, const char **parent_names,
> + int num_parents, void __iomem *reg, unsigned long flags);
> +
> +#define imx_clk_composite(name, parent_names, reg) \
> + imx_clk_composite_flags(name, parent_names, ARRAY_SIZE(parent_names), reg, \
> + CLK_SET_RATE_NO_REPARENT | CLK_OPS_PARENT_ENABLE)
> +
> +#define imx_clk_composite_critical(name, parent_names, reg) \
> + imx_clk_composite_flags(name, parent_names, ARRAY_SIZE(parent_names), reg, \
> + CLK_IS_CRITICAL | CLK_SET_RATE_NO_REPARENT | CLK_OPS_PARENT_ENABLE)
Another minor suggestion is to define a intermediary macro and define
both imx_clk_composite_critical() and imx_clk_composite() in terms of
it. Say:
#define __imx_clk_composite(name, parent_names, reg, flags) \
imx_clk_composite_flags(name, parent_names, ARRAY_SIZE(parent_names), reg, \
flags |
CLK_SET_RATE_NO_REPARENT | CLK_OPS_PARENT_ENABLE)
#define imx_clk_composite(name, parent_names, reg)
__imx_clk_composite_flags(name, parent_names, reg, 0)
#define imx_clk_composite_critical(name, parent_names, reg)
__imx_clk_composite_flags(name, parent_names, reg, CLK_IS_CRITICAL)
this way it might be a bit easier to spot that the only difference
between the two is CLK_IS_CRITICAL.
Thanks,
Andrey Smirnov
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