Commit 73118e61 authored by Jonghwa Lee's avatar Jonghwa Lee Committed by Mike Turquette
Browse files

clock: max77686: Add driver for Maxim 77686 32Khz crystal oscillator. 



This patch supports max77686 mfd's clock driver using common clock frame work.
max77686 has 3 clock ouputs which all are generated from crystal oscillator and
SOC can enable/disable them via I2C bus. All clocks are fixed-rate clock sources
so that it doesn't supply interface for changing clock rate.
Driver uses regmap API to communicate with internal register.

Signed-off-by: default avatarJonghwa Lee <jonghwa3.lee@samsung.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
parent ebc96db7

drivers/clk/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -47,4 +47,10 @@ config COMMON_CLK_VERSATILE 
          Supports clocking on ARM Reference designs Integrator/AP,

	  Integrator/CP, RealView PB1176, EB, PB11MP and PBX.



config COMMON_CLK_MAX77686

	tristate "Clock driver for Maxim 77686 MFD"

	depends on MFD_MAX77686

	---help---

	  This driver supports Maxim 77686 crystal oscillator clock. 



endmenu

drivers/clk/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -19,3 +19,4 @@ obj-$(CONFIG_ARCH_U8500) += ux500/ 


# Chip specific

obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o

obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o

drivers/clk/clk-max77686.c

0 → 100644
+244 −0
Original line number Diff line number Diff line 
/*

 * clk-max77686.c - Clock driver for Maxim 77686

 *

 * Copyright (C) 2012 Samsung Electornics

 * Jonghwa Lee <jonghwa3.lee@samsung.com>

 *

 * 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.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 */



#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/err.h>

#include <linux/platform_device.h>

#include <linux/mfd/max77686.h>

#include <linux/mfd/max77686-private.h>

#include <linux/clk-provider.h>

#include <linux/mutex.h>

#include <linux/clkdev.h>



enum {

	MAX77686_CLK_AP = 0,

	MAX77686_CLK_CP,

	MAX77686_CLK_PMIC,

	MAX77686_CLKS_NUM,

};



struct max77686_clk {

	struct max77686_dev *iodev;

	u32 mask;

	struct clk_hw hw;

	struct clk_lookup *lookup;

};



static struct max77686_clk *get_max77686_clk(struct clk_hw *hw)

{

	return container_of(hw, struct max77686_clk, hw);

}



static int max77686_clk_prepare(struct clk_hw *hw)

{

	struct max77686_clk *max77686;

	int ret;



	max77686 = get_max77686_clk(hw);

	if (!max77686)

		return -ENOMEM;



	ret = regmap_update_bits(max77686->iodev->regmap,

		MAX77686_REG_32KHZ, max77686->mask, max77686->mask);



	return ret;

}



static void max77686_clk_unprepare(struct clk_hw *hw)

{

	struct max77686_clk *max77686;



	max77686 = get_max77686_clk(hw);

	if (!max77686)

		return;



	regmap_update_bits(max77686->iodev->regmap,

		MAX77686_REG_32KHZ, max77686->mask, ~max77686->mask);

}



static int max77686_clk_is_enabled(struct clk_hw *hw)

{

	struct max77686_clk *max77686;

	int ret;

	u32 val;



	max77686 = get_max77686_clk(hw);

	if (!max77686)

		return -ENOMEM;



	ret = regmap_read(max77686->iodev->regmap,

				MAX77686_REG_32KHZ, &val);



	if (ret < 0)

		return -EINVAL;



	return val & max77686->mask;

}



static struct clk_ops max77686_clk_ops = {

	.prepare	= max77686_clk_prepare,

	.unprepare	= max77686_clk_unprepare,

	.is_enabled	= max77686_clk_is_enabled,

};



static struct clk_init_data max77686_clks_init[MAX77686_CLKS_NUM] = {

	[MAX77686_CLK_AP] = {

		.name = "32khz_ap",

		.ops = &max77686_clk_ops,

		.flags = CLK_IS_ROOT,

	},

	[MAX77686_CLK_CP] = {

		.name = "32khz_cp",

		.ops = &max77686_clk_ops,

		.flags = CLK_IS_ROOT,

	},

	[MAX77686_CLK_PMIC] = {

		.name = "32khz_pmic",

		.ops = &max77686_clk_ops,

		.flags = CLK_IS_ROOT,

	},

};



static int max77686_clk_register(struct device *dev,

				struct max77686_clk *max77686)

{

	struct clk *clk;

	struct clk_hw *hw = &max77686->hw;



	clk = clk_register(dev, hw);



	if (IS_ERR(clk))

		return -ENOMEM;



	max77686->lookup = devm_kzalloc(dev, sizeof(struct clk_lookup),

					GFP_KERNEL);

	if (IS_ERR(max77686->lookup))

		return -ENOMEM;



	max77686->lookup->con_id = hw->init->name;

	max77686->lookup->clk = clk;



	clkdev_add(max77686->lookup);



	return 0;

}



static __devinit int max77686_clk_probe(struct platform_device *pdev)

{

	struct max77686_dev *iodev = dev_get_drvdata(pdev->dev.parent);

	struct max77686_clk **max77686_clks;

	int i, ret;



	max77686_clks = devm_kzalloc(&pdev->dev, sizeof(struct max77686_clk *)

					* MAX77686_CLKS_NUM, GFP_KERNEL);

	if (IS_ERR(max77686_clks))

		return -ENOMEM;



	for (i = 0; i < MAX77686_CLKS_NUM; i++) {

		max77686_clks[i] = devm_kzalloc(&pdev->dev,

					sizeof(struct max77686_clk), GFP_KERNEL);

		if (IS_ERR(max77686_clks[i]))

			return -ENOMEM;

	}



	for (i = 0; i < MAX77686_CLKS_NUM; i++) {

		max77686_clks[i]->iodev = iodev;

		max77686_clks[i]->mask = 1 << i;

		max77686_clks[i]->hw.init = &max77686_clks_init[i];



		ret = max77686_clk_register(&pdev->dev, max77686_clks[i]);

		if (ret) {

			switch (i) {

			case MAX77686_CLK_AP:

				dev_err(&pdev->dev, "Fail to register CLK_AP\n");

				goto err_clk_ap;

				break;

			case MAX77686_CLK_CP:

				dev_err(&pdev->dev, "Fail to register CLK_CP\n");

				goto err_clk_cp;

				break;

			case MAX77686_CLK_PMIC:

				dev_err(&pdev->dev, "Fail to register CLK_PMIC\n");

				goto err_clk_pmic;

			}

		}

	}



	platform_set_drvdata(pdev, max77686_clks);



	goto out;



err_clk_pmic:

	clkdev_drop(max77686_clks[MAX77686_CLK_CP]->lookup);

	kfree(max77686_clks[MAX77686_CLK_CP]->hw.clk);

err_clk_cp:

	clkdev_drop(max77686_clks[MAX77686_CLK_AP]->lookup);

	kfree(max77686_clks[MAX77686_CLK_AP]->hw.clk);

err_clk_ap:

out:

	return ret;

}



static int __devexit max77686_clk_remove(struct platform_device *pdev)

{

	struct max77686_clk **max77686_clks = platform_get_drvdata(pdev);

	int i;



	for (i = 0; i < MAX77686_CLKS_NUM; i++) {

		clkdev_drop(max77686_clks[i]->lookup);

		kfree(max77686_clks[i]->hw.clk);

	}

	return 0;

}



static const struct platform_device_id max77686_clk_id[] = {

	{ "max77686-clk", 0},

	{ },

};

MODULE_DEVICE_TABLE(platform, max77686_clk_id);



static struct platform_driver max77686_clk_driver = {

	.driver = {

		.name  = "max77686-clk",

		.owner = THIS_MODULE,

	},

	.probe = max77686_clk_probe,

	.remove = __devexit_p(max77686_clk_remove),

	.id_table = max77686_clk_id,

};



static int __init max77686_clk_init(void)

{

	return platform_driver_register(&max77686_clk_driver);

}

subsys_initcall(max77686_clk_init);



static void __init max77686_clk_cleanup(void)

{

	platform_driver_unregister(&max77686_clk_driver);

}

module_exit(max77686_clk_cleanup);



MODULE_DESCRIPTION("MAXIM 77686 Clock Driver");

MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");

MODULE_LICENSE("GPL");

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