linux-kernel - Re: [RESEND/PATCH v6 2/3] clk: qcom: Add regmap mux-div clocks support

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Message-ID: <117afa56-b7ef-c141-c464-1868346380ed@linaro.org>
Date:   Fri, 28 Oct 2016 19:53:56 +0300
From:   Georgi Djakov <georgi.djakov@...aro.org>
To:     Stephen Boyd <sboyd@...eaurora.org>
Cc:     mturquette@...libre.com, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [RESEND/PATCH v6 2/3] clk: qcom: Add regmap mux-div clocks
 support

On 10/28/2016 04:59 AM, Stephen Boyd wrote:
> On 10/19, Georgi Djakov wrote:
>> diff --git a/drivers/clk/qcom/clk-regmap-mux-div.c b/drivers/clk/qcom/clk-regmap-mux-div.c
>> new file mode 100644
>> index 000000000000..ec87f496606a
>> --- /dev/null
>> +++ b/drivers/clk/qcom/clk-regmap-mux-div.c
>> @@ -0,0 +1,254 @@
>> +/*
>> + * Copyright (c) 2015, Linaro Limited
>> + * Copyright (c) 2014, The Linux Foundation. All rights reserved.
>> + *
>> + * This software is licensed under the terms of the GNU General Public
>> + * License version 2, as published by the Free Software Foundation, and
>> + * may be copied, distributed, and modified under those terms.
>> + *
>> + * This program is distributed in the hope that 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.
>> + */
>> +
>> +#include <linux/bitops.h>
>> +#include <linux/delay.h>
>> +#include <linux/export.h>
>
> Are symbols exported. They probably should be for modules.

In the next patch i am using __clk_lookup(), which is not exported, so i 
made this builtin too. Will remove <export.h> from here.

>
>> +#include <linux/kernel.h>
>> +#include <linux/regmap.h>
>> +
>> +#include "clk-regmap-mux-div.h"
>> +
>> +#define CMD_RCGR			0x0
>> +#define CMD_RCGR_UPDATE			BIT(0)
>> +#define CMD_RCGR_DIRTY_CFG		BIT(4)
>> +#define CMD_RCGR_ROOT_OFF		BIT(31)
>> +#define CFG_RCGR			0x4
>> +
>> +#define to_clk_regmap_mux_div(_hw) \
>> +	container_of(to_clk_regmap(_hw), struct clk_regmap_mux_div, clkr)
>> +
>> +int __mux_div_set_src_div(struct clk_regmap_mux_div *md, u32 src, u32 div)
>> +{
>> +	int ret, count;
>> +	u32 val, mask;
>> +	const char *name = clk_hw_get_name(&md->clkr.hw);
>> +
>> +	val = (div << md->hid_shift) | (src << md->src_shift);
>> +	mask = ((BIT(md->hid_width) - 1) << md->hid_shift) |
>> +	       ((BIT(md->src_width) - 1) << md->src_shift);
>> +
>> +	ret = regmap_update_bits(md->clkr.regmap, CFG_RCGR + md->reg_offset,
>> +				 mask, val);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = regmap_update_bits(md->clkr.regmap, CMD_RCGR + md->reg_offset,
>> +				 CMD_RCGR_UPDATE, CMD_RCGR_UPDATE);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* Wait for update to take effect */
>> +	for (count = 500; count > 0; count--) {
>> +		ret = regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset,
>> +				  &val);
>> +		if (ret)
>> +			return ret;
>> +		if (!(val & CMD_RCGR_UPDATE))
>> +			return 0;
>> +		udelay(1);
>> +	}
>> +
>> +	pr_err("%s: RCG did not update its configuration", name);
>> +	return -EBUSY;
>> +}
>> +
>> +static void __mux_div_get_src_div(struct clk_regmap_mux_div *md, u32 *src,
>> +				  u32 *div)
>> +{
>> +	u32 val, __div, __src;
>
> Perhaps just use d and s.
>

Ok.

>> +	const char *name = clk_hw_get_name(&md->clkr.hw);
>> +
>> +	regmap_read(md->clkr.regmap, CMD_RCGR + md->reg_offset, &val);
>> +
>> +	if (val & CMD_RCGR_DIRTY_CFG) {
>> +		pr_err("%s: RCG configuration is pending\n", name);
>> +		return;
>> +	}
>> +
>> +	regmap_read(md->clkr.regmap, CFG_RCGR + md->reg_offset, &val);
>> +	__src = (val >> md->src_shift);
>> +	__src &= BIT(md->src_width) - 1;
>> +	*src = __src;
>> +
>> +	__div = (val >> md->hid_shift);
>> +	__div &= BIT(md->hid_width) - 1;
>> +	*div = __div;
>> +}
>> +
>> +static unsigned long mux_div_recalc_rate(struct clk_hw *hw, unsigned long prate)
>> +{
>> +	struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
>> +	u32 div, src;
>> +	int i, num_parents = clk_hw_get_num_parents(hw);
>> +	const char *name = clk_hw_get_name(hw);
>> +
>> +	__mux_div_get_src_div(md, &src, &div);
>> +	for (i = 0; i < num_parents; i++)
>> +		if (src == md->parent_map[i].cfg) {
>> +			struct clk_hw *p = clk_hw_get_parent_by_index(hw, i);
>> +			unsigned long parent_rate = clk_hw_get_rate(p);
>> +
>> +			return mult_frac(parent_rate, 2, div + 1);
>> +		}
>> +
>> +	pr_err("%s: Can't find parent %d\n", name, src);
>> +	return 0;
>> +}
>> +
>> +static void mux_div_disable(struct clk_hw *hw)
>> +{
>> +	struct clk_regmap_mux_div *md = to_clk_regmap_mux_div(hw);
>> +
>> +	__mux_div_set_src_div(md, md->safe_src, md->safe_div);
>
> Ah this is to do magic tricks with cpuidle. In the android tree
> they call clk_disable() on the CPU clks from the idle path and
> that switches us over to the safe source and turns off the A53
> PLL while the CPU is not powered. That's all sort of sneaky and
> we're not doing that yet here so let's leave that until later.
> Please remove the enable/disable stuff.
>

Ok, agree! Its not used currently. Removed.