From: Tomasz Figa <tomasz.figa@gmail.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Stephen Boyd <sboyd@codeaurora.org>,
        Mike Turquette <mturquette@linaro.org>, linux-arm-msm@vger.kernel.org,
        Saravana Kannan <skannan@codeaurora.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 08/14] clk: msm: Add MSM clock driver
Date: Thu, 25 Jul 2013 10:32:09 +0200
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Hi Stephen,

On Wednesday 24 of July 2013 17:43:36 Stephen Boyd wrote:
> Add a clock driver that registers clocks from a DT node's
> 'clocks' child. Each new SoC will add a file describing the
> software interface and frequency plan to drivers/clk/msm/ and
> then hook that into the msm_cc_match_table by means of a
> compatible string and an msm_clk_match table.
> 
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> ---
>  drivers/clk/msm/Makefile   |   2 +
>  drivers/clk/msm/core.c     | 265
> +++++++++++++++++++++++++++++++++++++++++++++
> drivers/clk/msm/internal.h |  24 ++++
>  3 files changed, 291 insertions(+)
>  create mode 100644 drivers/clk/msm/core.c
>  create mode 100644 drivers/clk/msm/internal.h
> 
> diff --git a/drivers/clk/msm/Makefile b/drivers/clk/msm/Makefile
> index e1cee29..9cfd0d7 100644
> --- a/drivers/clk/msm/Makefile
> +++ b/drivers/clk/msm/Makefile
> @@ -4,3 +4,5 @@ clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-pll.o
>  clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-rcg.o
>  clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-rcg2.o
>  clk-msm-$(CONFIG_COMMON_CLK_MSM) += clk-branch.o
> +
> +clk-msm-$(CONFIG_COMMON_CLK_MSM) += core.o
> diff --git a/drivers/clk/msm/core.c b/drivers/clk/msm/core.c
> new file mode 100644
> index 0000000..b1904c0
> --- /dev/null
> +++ b/drivers/clk/msm/core.c
> @@ -0,0 +1,265 @@
> +/*
> + * Copyright (c) 2013, 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/err.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/spinlock.h>
> +
> +#include "internal.h"
> +#include "clk-pll.h"
> +#include "clk-rcg.h"
> +#include "clk-branch.h"
> +
> +struct cc_data {
> +	void __iomem *base;
> +	spinlock_t lock;
> +};
> +
> +static struct clk *
> +dispatch_fixed_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	u32 rate;
> +	const char *name = m->init_data->name;
> +
> +	if (of_property_read_u32(m->of_node, "clock-frequency", &rate))
> +		return ERR_PTR(-EINVAL);
> +
> +	return clk_register_fixed_rate(dev, name, NULL, CLK_IS_ROOT, 
rate);
> +}
> +
> +static struct clk *
> +dispatch_pll_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct pll_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return pll_clk_register(dev, desc, m->init_data);
> +}
> +
> +static struct clk *
> +dispatch_pll_vote_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct pll_vote_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return pll_vote_clk_register(dev, desc, m->init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_p2mn16_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct rcg_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_p2mn16_clk_register(dev, desc, &cc->lock, m-
>init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_p2mn8_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct rcg_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_p2mn8_clk_register(dev, desc, &cc->lock, m->init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_mn8_dyn_clk(struct of_clk_match *match, struct device
> *dev, +		struct cc_data *cc)
> +{
> +	struct rcg_dyn_desc *desc = match->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_mn8_dyn_clk_register(dev, desc, &cc->lock,
> +			match->init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_p4_dyn_clk(struct of_clk_match *match, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct rcg_dyn_desc *desc = match->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_p4_dyn_clk_register(dev, desc, &cc->lock,
> +			match->init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_h5mn8_clk(struct of_clk_match *match, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct rcg2_desc *desc = match->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_h5mn8_clk_register(dev, desc, &cc->lock, match-
>init_data);
> +}
> +
> +static struct clk *
> +dispatch_rcg_h5mn16_clk(struct of_clk_match *match, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct rcg2_desc *desc = match->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return rcg_h5mn16_clk_register(dev, desc, &cc->lock,
> match->init_data); +}
> +
> +static struct clk *
> +dispatch_branch_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct branch_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return branch_clk_register(dev, desc, &cc->lock, m->init_data);
> +}
> +
> +static struct clk *
> +dispatch_branch_hg_clk(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc)
> +{
> +	struct branch_desc *desc = m->driver_data;
> +
> +	desc->base = cc->base;
> +
> +	return branch_hg_clk_register(dev, desc, &cc->lock, m->init_data);
> +}
> +
> +static const struct of_device_id dispatch_table[] = {
> +	{ .compatible = "fixed-clock", .data = dispatch_fixed_clk },

This is already handled by the fixed-rate-clock driver and of_clk_init().

> +	{ .compatible = "qcom,pll", .data = dispatch_pll_clk },
> +	{ .compatible = "qcom,pll-vote", .data = dispatch_pll_vote_clk },
> +	{ .compatible = "qcom,p2-mn8-clock", .data = 
dispatch_rcg_p2mn8_clk },
> +	{ .compatible = "qcom,p2-mn16-clock", .data = 
dispatch_rcg_p2mn16_clk
> }, +	{ .compatible = "qcom,mn8-dyn-clock", .data =
> dispatch_rcg_mn8_dyn_clk }, +	{ .compatible = "qcom,p4-dyn-clock",
> .data = dispatch_rcg_p4_dyn_clk }, +	{ .compatible =
> "qcom,h5-mn8-clock", .data = dispatch_rcg_h5mn8_clk }, +	{ 
.compatible
> = "qcom,h5-mn16-clock", .data = dispatch_rcg_h5mn16_clk }, +	{
> .compatible = "qcom,cxc-clock", .data = dispatch_branch_clk }, +	{
> .compatible = "qcom,cxc-hg-clock", .data = dispatch_branch_hg_clk },
> +};

You can avoid all the code above by using OF_CLK_DECLARE() and 
of_clk_init().

> +typedef struct clk *
> +(*clk_dispatch_fn)(struct of_clk_match *m, struct device *dev,
> +		struct cc_data *cc);
> +
> +static const struct of_device_id msm_cc_match_table[] = {
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, msm_cc_match_table);
> +
> +static int msm_cc_probe(struct platform_device *pdev)
> +{
> +	struct cc_data *cc;
> +	void __iomem *base;
> +	struct resource *res;
> +	int count, i;
> +	const struct of_device_id *id_entry;
> +	const struct msm_clk_match *m;
> +	struct of_clk_match *matches;
> +	size_t size;
> +
> +	id_entry = of_match_device(msm_cc_match_table, &pdev->dev);
> +	m = id_entry->data;
> +	matches = m->matches;
> +	size = m->size;
> +
> +	cc = devm_kzalloc(&pdev->dev, sizeof(*cc), GFP_KERNEL);
> +	if (!cc)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base))
> +		return PTR_ERR(base);
> +
> +	cc->base = base;
> +	spin_lock_init(&cc->lock);
> +
> +	count = of_clk_match(&pdev->dev, matches, size);
> +	if (count < 0)
> +		return count;
> +
> +	for (i = 0; i < size; i++) {
> +		struct of_clk_match *match;
> +		const struct of_device_id *id;
> +		struct device_node *np;
> +		clk_dispatch_fn fn;
> +		struct clk *clk;
> +		int err;
> +
> +		match = &matches[i];
> +		np = match->of_node;
> +		if (!np)
> +			continue;
> +
> +		id = of_match_node(dispatch_table, match->of_node);
> +		if (!id)
> +			continue;
> +
> +		fn = id->data;
> +		clk = fn(match, &pdev->dev, cc);
> +		if (IS_ERR(clk))
> +			return PTR_ERR(clk);
> +
> +		err = of_clk_add_provider(np, of_clk_src_simple_get, clk);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct platform_driver msm_cc_driver = {
> +	.probe		= msm_cc_probe,
> +	.driver		= {
> +		.name	= "msm-clock",
> +		.owner	= THIS_MODULE,
> +		.of_match_table = msm_cc_match_table,
> +	},
> +};
> +
> +static int __init msm_cc_init(void)
> +{
> +	return platform_driver_register(&msm_cc_driver);
> +}
> +core_initcall(msm_cc_init);

I might be saying something stupid, but is it okay for a removable module 
to have a core_initcall?

Best regards,
Tomasz

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