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Date: Mon, 25 Mar 2013 16:43:43 -0700
From: Mike Turquette <mturquette@...aro.org>
To: Prashant Gaikwad <pgaikwad@...dia.com>, <hdoyu@...dia.com>,
<t.figa@...sung.com>
Cc: <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
Prashant Gaikwad <pgaikwad@...dia.com>
Subject: Re: [PATCH V3] clk: Add composite clock type
Quoting Prashant Gaikwad (2013-03-20 05:00:34)
> Not all clocks are required to be decomposed into basic clock
> types but at the same time want to use the functionality
> provided by these basic clock types instead of duplicating.
>
> For example, Tegra SoC has ~100 clocks which can be decomposed
> into Mux -> Div -> Gate clock types making the clock count to
> ~300. Also, parent change operation can not be performed on gate
> clock which forces to use mux clock in driver if want to change
> the parent.
>
> Instead aggregate the basic clock types functionality into one
> clock and just use this clock for all operations. This clock
> type re-uses the functionality of basic clock types and not
> limited to basic clock types but any hardware-specific
> implementation.
>
> Signed-off-by: Prashant Gaikwad <pgaikwad@...dia.com>
This version looks cleaner. Thanks for the respin. Taken into
clk-next.
Regards,
Mike
> ---
>
> Changes from V2:
> - Move clk_ops inside clk_composite instead of dynamically allocation.
>
> ---
> drivers/clk/Makefile | 1 +
> drivers/clk/clk-composite.c | 201 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/clk-provider.h | 31 +++++++
> 3 files changed, 233 insertions(+), 0 deletions(-)
> create mode 100644 drivers/clk/clk-composite.c
>
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index 0147022..097ed01 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -7,6 +7,7 @@ obj-$(CONFIG_COMMON_CLK) += clk-fixed-factor.o
> obj-$(CONFIG_COMMON_CLK) += clk-fixed-rate.o
> obj-$(CONFIG_COMMON_CLK) += clk-gate.o
> obj-$(CONFIG_COMMON_CLK) += clk-mux.o
> +obj-$(CONFIG_COMMON_CLK) += clk-composite.o
>
> # SoCs specific
> obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
> diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
> new file mode 100644
> index 0000000..097dee4
> --- /dev/null
> +++ b/drivers/clk/clk-composite.c
> @@ -0,0 +1,201 @@
> +/*
> + * Copyright (c) 2013 NVIDIA CORPORATION. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/err.h>
> +#include <linux/slab.h>
> +
> +#define to_clk_composite(_hw) container_of(_hw, struct clk_composite, hw)
> +
> +static u8 clk_composite_get_parent(struct clk_hw *hw)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *mux_ops = composite->mux_ops;
> + struct clk_hw *mux_hw = composite->mux_hw;
> +
> + mux_hw->clk = hw->clk;
> +
> + return mux_ops->get_parent(mux_hw);
> +}
> +
> +static int clk_composite_set_parent(struct clk_hw *hw, u8 index)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *mux_ops = composite->mux_ops;
> + struct clk_hw *mux_hw = composite->mux_hw;
> +
> + mux_hw->clk = hw->clk;
> +
> + return mux_ops->set_parent(mux_hw, index);
> +}
> +
> +static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *div_ops = composite->div_ops;
> + struct clk_hw *div_hw = composite->div_hw;
> +
> + div_hw->clk = hw->clk;
> +
> + return div_ops->recalc_rate(div_hw, parent_rate);
> +}
> +
> +static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long *prate)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *div_ops = composite->div_ops;
> + struct clk_hw *div_hw = composite->div_hw;
> +
> + div_hw->clk = hw->clk;
> +
> + return div_ops->round_rate(div_hw, rate, prate);
> +}
> +
> +static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *div_ops = composite->div_ops;
> + struct clk_hw *div_hw = composite->div_hw;
> +
> + div_hw->clk = hw->clk;
> +
> + return div_ops->set_rate(div_hw, rate, parent_rate);
> +}
> +
> +static int clk_composite_is_enabled(struct clk_hw *hw)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *gate_ops = composite->gate_ops;
> + struct clk_hw *gate_hw = composite->gate_hw;
> +
> + gate_hw->clk = hw->clk;
> +
> + return gate_ops->is_enabled(gate_hw);
> +}
> +
> +static int clk_composite_enable(struct clk_hw *hw)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *gate_ops = composite->gate_ops;
> + struct clk_hw *gate_hw = composite->gate_hw;
> +
> + gate_hw->clk = hw->clk;
> +
> + return gate_ops->enable(gate_hw);
> +}
> +
> +static void clk_composite_disable(struct clk_hw *hw)
> +{
> + struct clk_composite *composite = to_clk_composite(hw);
> + const struct clk_ops *gate_ops = composite->gate_ops;
> + struct clk_hw *gate_hw = composite->gate_hw;
> +
> + gate_hw->clk = hw->clk;
> +
> + gate_ops->disable(gate_hw);
> +}
> +
> +struct clk *clk_register_composite(struct device *dev, const char *name,
> + const char **parent_names, int num_parents,
> + struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
> + struct clk_hw *div_hw, const struct clk_ops *div_ops,
> + struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
> + unsigned long flags)
> +{
> + struct clk *clk;
> + struct clk_init_data init;
> + struct clk_composite *composite;
> + struct clk_ops *clk_composite_ops;
> +
> + composite = kzalloc(sizeof(*composite), GFP_KERNEL);
> + if (!composite) {
> + pr_err("%s: could not allocate composite clk\n", __func__);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + init.name = name;
> + init.flags = flags | CLK_IS_BASIC;
> + init.parent_names = parent_names;
> + init.num_parents = num_parents;
> +
> + clk_composite_ops = &composite->ops;
> +
> + if (mux_hw && mux_ops) {
> + if (!mux_ops->get_parent || !mux_ops->set_parent) {
> + clk = ERR_PTR(-EINVAL);
> + goto err;
> + }
> +
> + composite->mux_hw = mux_hw;
> + composite->mux_ops = mux_ops;
> + clk_composite_ops->get_parent = clk_composite_get_parent;
> + clk_composite_ops->set_parent = clk_composite_set_parent;
> + }
> +
> + if (div_hw && div_ops) {
> + if (!div_ops->recalc_rate || !div_ops->round_rate ||
> + !div_ops->set_rate) {
> + clk = ERR_PTR(-EINVAL);
> + goto err;
> + }
> +
> + composite->div_hw = div_hw;
> + composite->div_ops = div_ops;
> + clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
> + clk_composite_ops->round_rate = clk_composite_round_rate;
> + clk_composite_ops->set_rate = clk_composite_set_rate;
> + }
> +
> + if (gate_hw && gate_ops) {
> + if (!gate_ops->is_enabled || !gate_ops->enable ||
> + !gate_ops->disable) {
> + clk = ERR_PTR(-EINVAL);
> + goto err;
> + }
> +
> + composite->gate_hw = gate_hw;
> + composite->gate_ops = gate_ops;
> + clk_composite_ops->is_enabled = clk_composite_is_enabled;
> + clk_composite_ops->enable = clk_composite_enable;
> + clk_composite_ops->disable = clk_composite_disable;
> + }
> +
> + init.ops = clk_composite_ops;
> + composite->hw.init = &init;
> +
> + clk = clk_register(dev, &composite->hw);
> + if (IS_ERR(clk))
> + goto err;
> +
> + if (composite->mux_hw)
> + composite->mux_hw->clk = clk;
> +
> + if (composite->div_hw)
> + composite->div_hw->clk = clk;
> +
> + if (composite->gate_hw)
> + composite->gate_hw->clk = clk;
> +
> + return clk;
> +
> +err:
> + kfree(composite);
> + return clk;
> +}
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 7f197d7..33e7e64 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -325,6 +325,37 @@ struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
> const char *parent_name, unsigned long flags,
> unsigned int mult, unsigned int div);
>
> +/***
> + * struct clk_composite - aggregate clock of mux, divider and gate clocks
> + *
> + * @hw: handle between common and hardware-specific interfaces
> + * @mux_hw: handle between composite and hardware-specifix mux clock
> + * @div_hw: handle between composite and hardware-specifix divider clock
> + * @gate_hw: handle between composite and hardware-specifix gate clock
> + * @mux_ops: clock ops for mux
> + * @div_ops: clock ops for divider
> + * @gate_ops: clock ops for gate
> + */
> +struct clk_composite {
> + struct clk_hw hw;
> + struct clk_ops ops;
> +
> + struct clk_hw *mux_hw;
> + struct clk_hw *div_hw;
> + struct clk_hw *gate_hw;
> +
> + const struct clk_ops *mux_ops;
> + const struct clk_ops *div_ops;
> + const struct clk_ops *gate_ops;
> +};
> +
> +struct clk *clk_register_composite(struct device *dev, const char *name,
> + const char **parent_names, int num_parents,
> + struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
> + struct clk_hw *div_hw, const struct clk_ops *div_ops,
> + struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
> + unsigned long flags);
> +
> /**
> * clk_register - allocate a new clock, register it and return an opaque cookie
> * @dev: device that is registering this clock
> --
> 1.7.4.1
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