linux-kernel - Re: [PATCH v5 3/3] clk: meson: add sub MMC clock controller driver

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Message-ID: <01d07c83-b17e-70b5-6e9b-8150ee3aedf2@amlogic.com>
Date:   Sat, 20 Oct 2018 00:12:53 +0800
From:   Jianxin Pan <jianxin.pan@...ogic.com>
To:     Stephen Boyd <sboyd@...nel.org>,
        Jerome Brunet <jbrunet@...libre.com>,
        Neil Armstrong <narmstrong@...libre.com>
CC:     Yixun Lan <yixun.lan@...ogic.com>,
        Kevin Hilman <khilman@...libre.com>,
        Carlo Caione <carlo@...one.org>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Herring <robh@...nel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Boris Brezillon <boris.brezillon@...tlin.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Liang Yang <liang.yang@...ogic.com>,
        Jian Hu <jian.hu@...ogic.com>,
        Qiufang Dai <qiufang.dai@...ogic.com>,
        Hanjie Lin <hanjie.lin@...ogic.com>,
        Victor Wan <victor.wan@...ogic.com>,
        <linux-clk@...r.kernel.org>, <linux-amlogic@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 3/3] clk: meson: add sub MMC clock controller driver

On 2018/10/19 1:13, Stephen Boyd wrote:
> Quoting Jianxin Pan (2018-10-17 22:07:25)
>> diff --git a/drivers/clk/meson/clk-regmap.c b/drivers/clk/meson/clk-regmap.c
>> index 305ee30..f96314d 100644
>> --- a/drivers/clk/meson/clk-regmap.c
>> +++ b/drivers/clk/meson/clk-regmap.c
>> @@ -113,8 +113,25 @@ static int clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
>>                                   clk_div_mask(div->width) << div->shift, val);
>>  };
>>  
>> -/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */
>> +static void clk_regmap_div_init(struct clk_hw *hw)
>> +{
>> +       struct clk_regmap *clk = to_clk_regmap(hw);
>> +       struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
>> +       unsigned int val;
>> +       int ret;
>> +
>> +       ret = regmap_read(clk->map, div->offset, &val);
>> +       if (ret)
>> +               return;
>>  
>> +       val &= (clk_div_mask(div->width) << div->shift);
>> +       if (!val)
>> +               regmap_update_bits(clk->map, div->offset,
>> +                                  clk_div_mask(div->width) << div->shift,
>> +                                  clk_div_mask(div->width));
>> +}
>> +
>> +/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */
> 
> We should add a patch to rename the symbol for qcom, i.e.
> qcom_clk_regmap_div_ro_ops, and then any symbols in this directory
> should be meson_clk_regmap_div_ro_ops.
"/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */"
This comment is not introduced in this patch.
I followed the naming style in this file and add clk_regmap_divider_with_init_ops.

@Jerome， What's your suggestion about this？
> 
> Or we should just give up and squash the regmap implementations together
> into a new clk_regmap set of ops.
> 
>>  const struct clk_ops clk_regmap_divider_ops = {
>>         .recalc_rate = clk_regmap_div_recalc_rate,
>>         .round_rate = clk_regmap_div_round_rate,
>> diff --git a/drivers/clk/meson/mmc-clkc.c b/drivers/clk/meson/mmc-clkc.c
>> new file mode 100644
>> index 0000000..5555e3f
>> --- /dev/null
>> +++ b/drivers/clk/meson/mmc-clkc.c
>> @@ -0,0 +1,296 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Amlogic Meson MMC Sub Clock Controller Driver
>> + *
>> + * Copyright (c) 2017 Baylibre SAS.
>> + * Author: Jerome Brunet <jbrunet@...libre.com>
>> + *
>> + * Copyright (c) 2018 Amlogic, inc.
>> + * Author: Yixun Lan <yixun.lan@...ogic.com>
>> + */
>> +
>> +#include <linux/clk.h>
> 
> clk-provider.h instead of clk.h?
OK.
> 
>> +#include <linux/module.h>
>> +#include <linux/regmap.h>
>> +#include <linux/slab.h>
>> +#include <linux/of_device.h>
>> +#include <linux/mfd/syscon.h>
>> +#include <linux/platform_device.h>
>> +#include <dt-bindings/clock/amlogic,mmc-clkc.h>
>> +
>> +
> [...]
>> +
>> +static struct clk_regmap *
>> +mmc_clkc_register_clk_with_parent(struct device *dev, struct regmap *map,
>> +                                 char *suffix, const char *parent,
>> +                                 unsigned long flags,
>> +                                 const struct clk_ops *ops, void *data)
>> +{
>> +       struct clk_init_data init;
>> +       struct clk_regmap *clk;
>> +
>> +       init.ops = ops;
>> +       init.flags = flags;
>> +       init.parent_names = (const char* const []){ parent, };
> 
> Can't we just assign &parent here?
OK. I will fix it in the next version.
> 
>> +       init.num_parents = 1;
>> +
>> +       clk = mmc_clkc_register_clk(dev, map, &init, suffix, data);
>> +       if (IS_ERR(clk))
>> +               dev_err(dev, "Core %s clock registration failed\n", suffix);
>> +
>> +       return clk;
>> +}
>> +
>> +static int mmc_clkc_probe(struct platform_device *pdev)
>> +{
>> +       struct clk_hw_onecell_data *onecell_data;
>> +       struct device *dev = &pdev->dev;
>> +       struct mmc_clkc_data *data;
>> +       struct regmap *map;
>> +       struct clk_regmap *mux, *div, *core, *rx, *tx;
>> +
>> +       data = (struct mmc_clkc_data *)of_device_get_match_data(dev);
> 
> Nitpick: Drop the cast.
OK. I will drop it.
Thanks for the review.

> 
>> +       if (!data)
>> +               return -ENODEV;
>> +
>> +       map = syscon_node_to_regmap(dev->of_node);
> 
> .
>