Re: [PATCH v3 05/14] clk: Add generic driver for Maxim PMIC clocks

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On czw, 2014-06-19 at 20:20 +0200, Javier Martinez Canillas wrote:
> Maxim Integrated Power Management ICs are very similar with
> regard to their clock outputs. Most of the clock drivers for
> these chips are duplicating code and are simpler enough that
> can be converted to use a generic driver to consolidate code
> and avoid duplication.
> 
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>

(...)

> diff --git a/drivers/clk/clk-max-gen.c b/drivers/clk/clk-max-gen.c
> new file mode 100644
> index 0000000..aa9ebbe
> --- /dev/null
> +++ b/drivers/clk/clk-max-gen.c
> @@ -0,0 +1,197 @@
> +/*
> + * clk-max-gen.c - Generic clock driver for Maxim PMICs clocks
> + *
> + * Copyright (C) 2012 Samsung Electornics
> + * Jonghwa Lee <jonghwa3.lee@samsung.com>

You copied this from original file but '2012' and author look a little
strange since this piece of work is actually new stuff. Maybe consider
adding current copyright?

> + *
> + * This program is free software; you can redistribute  it and/or modify it
> + * under  the terms of  the GNU General  Public License as published by the
> + * Free Software Foundation;  either version 2 of the  License, or (at your
> + * option) any later version.
> + *
> + * 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.
> + *
> + * This driver is based on clk-max77686.c
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/err.h>
> +#include <linux/regmap.h>
> +#include <linux/platform_device.h>
> +#include <linux/clk-provider.h>
> +#include <linux/mutex.h>
> +#include <linux/clkdev.h>
> +
> +struct max_gen_clk {
> +	struct regmap *regmap;
> +	u32 mask;
> +	u32 reg;
> +	struct clk_hw hw;
> +	struct clk_lookup *lookup;
> +};
> +
> +static struct max_gen_clk *to_max_gen_clk(struct clk_hw *hw)
> +{
> +	return container_of(hw, struct max_gen_clk, hw);
> +}
> +
> +static int max_gen_clk_prepare(struct clk_hw *hw)
> +{
> +	struct max_gen_clk *max_gen = to_max_gen_clk(hw);
> +
> +	return regmap_update_bits(max_gen->regmap, max_gen->reg,
> +				  max_gen->mask, max_gen->mask);
> +}
> +
> +static void max_gen_clk_unprepare(struct clk_hw *hw)
> +{
> +	struct max_gen_clk *max_gen = to_max_gen_clk(hw);
> +
> +	regmap_update_bits(max_gen->regmap, max_gen->reg,
> +			   max_gen->mask, ~max_gen->mask);
> +}
> +
> +static int max_gen_clk_is_prepared(struct clk_hw *hw)
> +{
> +	struct max_gen_clk *max_gen = to_max_gen_clk(hw);
> +	int ret;
> +	u32 val;
> +
> +	ret = regmap_read(max_gen->regmap, max_gen->reg, &val);
> +
> +	if (ret < 0)
> +		return -EINVAL;
> +
> +	return val & max_gen->mask;
> +}
> +
> +static unsigned long max_gen_recalc_rate(struct clk_hw *hw,
> +					 unsigned long parent_rate)
> +{
> +	return 32768;
> +}
> +
> +struct clk_ops max_gen_clk_ops = {
> +	.prepare	= max_gen_clk_prepare,
> +	.unprepare	= max_gen_clk_unprepare,
> +	.is_prepared	= max_gen_clk_is_prepared,
> +	.recalc_rate	= max_gen_recalc_rate,
> +};
> +
> +static struct clk *max_gen_clk_register(struct device *dev,
> +					struct max_gen_clk *max_gen)
> +{
> +	struct clk *clk;
> +	struct clk_hw *hw = &max_gen->hw;
> +
> +	clk = clk_register(dev, hw);
> +	if (IS_ERR(clk))
> +		return clk;
> +
> +	max_gen->lookup = kzalloc(sizeof(struct clk_lookup), GFP_KERNEL);
> +	if (!max_gen->lookup)
> +		return ERR_PTR(-ENOMEM);
> +
> +	max_gen->lookup->con_id = hw->init->name;
> +	max_gen->lookup->clk = clk;
> +
> +	clkdev_add(max_gen->lookup);
> +
> +	return clk;
> +}
> +
> +int max_gen_clk_probe(struct platform_device *pdev, struct regmap *regmap,
> +		      u32 reg, struct clk_init_data *clks_init, int num_init)
> +{
> +	int i, ret;
> +	struct max_gen_clk **max_gen_clks;
> +	struct clk **clocks;
> +	struct device *dev = &pdev->dev;
> +
> +	clocks = devm_kzalloc(dev, sizeof(struct clk *) * num_init, GFP_KERNEL);
> +	if (!clocks)
> +		return -ENOMEM;
> +
> +	max_gen_clks = devm_kzalloc(dev, sizeof(struct max_gen_clk *)
> +				    * num_init, GFP_KERNEL);
> +	if (!max_gen_clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_init; i++) {
> +		max_gen_clks[i] = devm_kzalloc(dev, sizeof(struct max_gen_clk),
> +					       GFP_KERNEL);
> +		if (!max_gen_clks[i])
> +			return -ENOMEM;
> +	}

Why don't use only one devm_kzalloc() call for struct max_gen_clk?
Something like:
	max_gen_clks = devm_kzalloc(dev, sizeof(struct max_gen_clk)
				    * num_init, GFP_KERNEL);

This will be shorter and still readable.

> +
> +	for (i = 0; i < num_init; i++) {
> +		max_gen_clks[i]->regmap = regmap;
> +		max_gen_clks[i]->mask = 1 << i;
> +		max_gen_clks[i]->reg = reg;
> +		max_gen_clks[i]->hw.init = &clks_init[i];
> +
> +		clocks[i] = max_gen_clk_register(dev, max_gen_clks[i]);
> +		if (IS_ERR(clocks[i])) {
> +			ret = PTR_ERR(clocks[i]);
> +			dev_err(dev, "failed to register %s\n",
> +				max_gen_clks[i]->hw.init->name);
> +			goto err_clocks;
> +		}
> +	}
> +
> +	platform_set_drvdata(pdev, clocks);
> +
> +	if (dev->of_node) {
> +		struct clk_onecell_data *of_data;
> +
> +		of_data = devm_kzalloc(dev, sizeof(*of_data), GFP_KERNEL);
> +		if (!of_data) {
> +			ret = -ENOMEM;
> +			goto err_clocks;
> +		}
> +
> +		of_data->clks = clocks;
> +		of_data->clk_num = num_init;
> +		ret = of_clk_add_provider(dev->of_node, of_clk_src_onecell_get,
> +					  of_data);
> +
> +		if (ret) {
> +			dev_err(dev, "failed to register OF clock provider\n");
> +			goto err_clocks;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_clocks:
> +	for (--i; i >= 0; --i) {
> +		clkdev_drop(max_gen_clks[i]->lookup);
> +		clk_unregister(max_gen_clks[i]->hw.clk);
> +	}
> +
> +	return ret;
> +}

Since users of this function may be compiled as modules these should be
exported (EXPORT_SYMBOL(_GPL)):
ERROR: "max_gen_clk_ops" [drivers/clk/clk-max77802.ko] undefined!
ERROR: "max_gen_clk_probe" [drivers/clk/clk-max77802.ko] undefined!
ERROR: "max_gen_clk_remove" [drivers/clk/clk-max77802.ko] undefined!
ERROR: "max_gen_clk_ops" [drivers/clk/clk-max77686.ko] undefined!
ERROR: "max_gen_clk_probe" [drivers/clk/clk-max77686.ko] undefined!
ERROR: "max_gen_clk_remove" [drivers/clk/clk-max77686.ko] undefined!

Best regards,
Krzysztof