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Message-ID: <146800242289.73491.4169295036354147972@resonance>
Date: Fri, 08 Jul 2016 11:27:02 -0700
From: Michael Turquette <mturquette@...libre.com>
To: Gregory CLEMENT <gregory.clement@...e-electrons.com>,
"Stephen Boyd" <sboyd@...eaurora.org>, linux-clk@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: "Rob Herring" <robh+dt@...nel.org>, devicetree@...r.kernel.org,
"Jason Cooper" <jason@...edaemon.net>,
"Andrew Lunn" <andrew@...n.ch>,
"Sebastian Hesselbarth" <sebastian.hesselbarth@...il.com>,
"Gregory CLEMENT" <gregory.clement@...e-electrons.com>,
"Thomas Petazzoni" <thomas.petazzoni@...e-electrons.com>,
linux-arm-kernel@...ts.infradead.org,
"Nadav Haklai" <nadavh@...vell.com>,
"Victor Gu" <xigu@...vell.com>,
"Romain Perier" <romain.perier@...e-electrons.com>,
"Omri Itach" <omrii@...vell.com>,
"Marcin Wojtas" <mw@...ihalf.com>,
"Wilson Ding" <dingwei@...vell.com>,
"Hua Jing" <jinghua@...vell.com>, "Terry Zhou" <bjzhou@...vell.com>
Subject: Re: [PATCH v2 6/6] clk: mvebu: Add the peripheral clock driver for Armada
3700
Quoting Gregory CLEMENT (2016-07-07 15:37:51)
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>
Same question as my previous email. Is clk.h necessary? Is this driver
also a clk consumer?
> +static int armada_3700_add_composite_clk(const struct clk_periph_data *data,
> + const char * const *parent_name,
> + void __iomem *reg, spinlock_t *lock,
> + struct device *dev, struct clk_hw *hw)
> +{
> + const struct clk_ops *mux_ops = NULL, *gate_ops = NULL,
> + *div_ops = NULL;
> + struct clk_hw *mux_hw = NULL, *gate_hw = NULL, *div_hw = NULL;
> + const char * const *names;
> + struct clk_mux *mux = NULL;
> + struct clk_gate *gate = NULL;
> + struct clk_divider *div = NULL;
> + struct clk_double_div *double_div = NULL;
> + int num_parent;
> + int ret = 0;
> +
> + if (data->gate_shift != UNUSED) {
> + gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
> +
> + if (!gate)
> + return -ENOMEM;
> +
> + gate->reg = reg + CLK_DIS;
> + gate->bit_idx = data->gate_shift;
> + gate->lock = lock;
> + gate_ops = &clk_gate_ops;
> + gate_hw = &gate->hw;
> + }
> +
> + if (data->mux_shift != UNUSED) {
> + mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
> +
> + if (!mux) {
> + ret = -ENOMEM;
> + goto free_gate;
> + }
> +
> + mux->reg = reg + TBG_SEL;
> + mux->shift = data->mux_shift;
> + mux->mask = 0x3;
> + mux->lock = lock;
> + mux_ops = &clk_mux_ro_ops;
> + mux_hw = &mux->hw;
> + }
> +
> + if (data->div_reg1 != UNUSED) {
> + if (data->div_reg2 == UNUSED) {
> + const struct clk_div_table *clkt;
> + int table_size = 0;
> +
> + div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
> + if (!div) {
> + ret = -ENOMEM;
> + goto free_mux;
> + }
> +
> + div->reg = reg + data->div_reg1;
> + div->table = data->table;
> + for (clkt = div->table; clkt->div; clkt++)
> + table_size++;
> + div->width = order_base_2(table_size);
> + div->lock = lock;
> + div_ops = &clk_divider_ro_ops;
> + div_hw = &div->hw;
> + } else {
> + double_div = devm_kzalloc(dev, sizeof(*double_div),
> + GFP_KERNEL);
> + if (!double_div) {
> + ret = -ENOMEM;
> + goto free_mux;
> + }
> +
> + double_div->reg1 = reg + data->div_reg1;
> + double_div->shift1 = data->div_shift1;
> + double_div->reg2 = reg + data->div_reg1;
> + double_div->shift2 = data->div_shift2;
> + div_ops = &clk_double_div_ops;
> + div_hw = &double_div->hw;
> + }
> + }
> +
> + switch (data->flags) {
> + case XTAL_CHILD:
> + /* the xtal clock is the 5th clock */
> + names = &parent_name[4];
> + num_parent = 1;
> + break;
> + case TBGA_S_CHILD:
> + /* the TBG A S clock is the 3rd clock */
> + names = &parent_name[2];
> + num_parent = 1;
> + break;
> + case GBE_CORE_CHILD:
> + names = &gbe_name[1];
> + num_parent = 1;
> + break;
> + case GBE_50_CHILD:
> + names = &gbe_name[0];
> + num_parent = 1;
> + break;
> + case GBE_125_CHILD:
> + names = &gbe_name[2];
> + num_parent = 1;
> + break;
> + default:
> + names = parent_name;
> + num_parent = 4;
> + }
> + hw = clk_hw_register_composite(dev, data->name,
> + names, num_parent,
> + mux_hw, mux_ops,
> + div_hw, div_ops,
> + gate_hw, gate_ops,
> + CLK_IGNORE_UNUSED);
> + if (IS_ERR(hw)) {
> + ret = PTR_ERR(hw);
> + goto free_div;
> + }
> +
> + return 0;
> +free_div:
> + devm_kfree(dev, div);
> + devm_kfree(dev, double_div);
> +free_mux:
> + devm_kfree(dev, mux);
> +free_gate:
> + devm_kfree(dev, gate);
> + return ret;
> +}
Can this "add" function (aka registration function) be replaced with
static data instead? I think that all of the static data exists already,
this function can be removed and your probe can call clk_hw_register
directly.
It might need a macro though, since composite clock structures are
rather messy. This avoids a lot of unnecessary allocations and time
populating data that we already have access to. In general I am trying
to encourage clk drivers to use only clk_hw_register() in their probe
instead of the helper registration functions.
Similarly I am discouraging drivers from populating hw.init at run-time,
since we already have that data for that at compile-time.
Regards,
Mike
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