[linux-2.6-block.git] / drivers / w1 / masters / mxc_w1.c

/*
 * Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Luotao Fu, kernel@pengutronix.de
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>

#include "../w1.h"
#include "../w1_int.h"
#include "../w1_log.h"

/* According to the mx27 Datasheet the reset procedure should take up to about
 * 1350us. We set the timeout to 500*100us = 50ms for sure */
#define MXC_W1_RESET_TIMEOUT 500

/*
 * MXC W1 Register offsets
 */
#define MXC_W1_CONTROL          0x00
#define MXC_W1_TIME_DIVIDER     0x02
#define MXC_W1_RESET            0x04
#define MXC_W1_COMMAND          0x06
#define MXC_W1_TXRX             0x08
#define MXC_W1_INTERRUPT        0x0A
#define MXC_W1_INTERRUPT_EN     0x0C

struct mxc_w1_device {
	void __iomem *regs;
	unsigned int clkdiv;
	struct clk *clk;
	struct w1_bus_master bus_master;
};

/*
 * this is the low level routine to
 * reset the device on the One Wire interface
 * on the hardware
 */
static u8 mxc_w1_ds2_reset_bus(void *data)
{
	u8 reg_val;
	unsigned int timeout_cnt = 0;
	struct mxc_w1_device *dev = data;

	__raw_writeb(0x80, (dev->regs + MXC_W1_CONTROL));

	while (1) {
		reg_val = __raw_readb(dev->regs + MXC_W1_CONTROL);

		if (((reg_val >> 7) & 0x1) == 0 ||
		    timeout_cnt > MXC_W1_RESET_TIMEOUT)
			break;
		else
			timeout_cnt++;

		udelay(100);
	}
	return (reg_val >> 7) & 0x1;
}

/*
 * this is the low level routine to read/write a bit on the One Wire
 * interface on the hardware. It does write 0 if parameter bit is set
 * to 0, otherwise a write 1/read.
 */
static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
{
	struct mxc_w1_device *mdev = data;
	void __iomem *ctrl_addr = mdev->regs + MXC_W1_CONTROL;
	unsigned int timeout_cnt = 400; /* Takes max. 120us according to
					 * datasheet.
					 */

	__raw_writeb((1 << (5 - bit)), ctrl_addr);

	while (timeout_cnt--) {
		if (!((__raw_readb(ctrl_addr) >> (5 - bit)) & 0x1))
			break;

		udelay(1);
	}

	return ((__raw_readb(ctrl_addr)) >> 3) & 0x1;
}

static int __devinit mxc_w1_probe(struct platform_device *pdev)
{
	struct mxc_w1_device *mdev;
	struct resource *res;
	int err = 0;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -ENODEV;

	mdev = kzalloc(sizeof(struct mxc_w1_device), GFP_KERNEL);
	if (!mdev)
		return -ENOMEM;

	mdev->clk = clk_get(&pdev->dev, "owire");
	if (!mdev->clk) {
		err = -ENODEV;
		goto failed_clk;
	}

	mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1;

	res = request_mem_region(res->start, resource_size(res),
				"mxc_w1");
	if (!res) {
		err = -EBUSY;
		goto failed_req;
	}

	mdev->regs = ioremap(res->start, resource_size(res));
	if (!mdev->regs) {
		printk(KERN_ERR "Cannot map frame buffer registers\n");
		goto failed_ioremap;
	}

	clk_enable(mdev->clk);
	__raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER);

	mdev->bus_master.data = mdev;
	mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus;
	mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit;

	err = w1_add_master_device(&mdev->bus_master);

	if (err)
		goto failed_add;

	platform_set_drvdata(pdev, mdev);
	return 0;

failed_add:
	iounmap(mdev->regs);
failed_ioremap:
	release_mem_region(res->start, resource_size(res));
failed_req:
	clk_put(mdev->clk);
failed_clk:
	kfree(mdev);
	return err;
}

/*
 * disassociate the w1 device from the driver
 */
static int __devexit mxc_w1_remove(struct platform_device *pdev)
{
	struct mxc_w1_device *mdev = platform_get_drvdata(pdev);
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	w1_remove_master_device(&mdev->bus_master);

	iounmap(mdev->regs);
	release_mem_region(res->start, resource_size(res));
	clk_disable(mdev->clk);
	clk_put(mdev->clk);

	platform_set_drvdata(pdev, NULL);

	return 0;
}

static struct platform_driver mxc_w1_driver = {
	.driver = {
		   .name = "mxc_w1",
	},
	.probe = mxc_w1_probe,
	.remove = mxc_w1_remove,
};

static int __init mxc_w1_init(void)
{
	return platform_driver_register(&mxc_w1_driver);
}

static void mxc_w1_exit(void)
{
	platform_driver_unregister(&mxc_w1_driver);
}

module_init(mxc_w1_init);
module_exit(mxc_w1_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Freescale Semiconductors Inc");
MODULE_DESCRIPTION("Driver for One-Wire on MXC");
Commit	Line	Data
a5fd9139 SH	1	/*
	2	* Copyright 2005-2008 Freescale Semiconductor, Inc. All Rights Reserved.
	3	* Copyright 2008 Luotao Fu, kernel@pengutronix.de
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version 2
	8	* of the License, or (at your option) any later version.
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write to the Free Software
	16	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
	17	*
	18	*/
	19
	20	#include <linux/module.h>
	21	#include <linux/interrupt.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/clk.h>
	24	#include <linux/delay.h>
	25	#include <linux/io.h>
	26
	27	#include "../w1.h"
	28	#include "../w1_int.h"
	29	#include "../w1_log.h"
	30
	31	/* According to the mx27 Datasheet the reset procedure should take up to about
	32	* 1350us. We set the timeout to 500100us = 50ms for sure /
	33	#define MXC_W1_RESET_TIMEOUT 500
	34
	35	/*
	36	* MXC W1 Register offsets
	37	*/
	38	#define MXC_W1_CONTROL 0x00
	39	#define MXC_W1_TIME_DIVIDER 0x02
	40	#define MXC_W1_RESET 0x04
	41	#define MXC_W1_COMMAND 0x06
	42	#define MXC_W1_TXRX 0x08
	43	#define MXC_W1_INTERRUPT 0x0A
	44	#define MXC_W1_INTERRUPT_EN 0x0C
	45
	46	struct mxc_w1_device {
	47	void __iomem *regs;
	48	unsigned int clkdiv;
	49	struct clk *clk;
	50	struct w1_bus_master bus_master;
	51	};
	52
	53	/*
	54	* this is the low level routine to
	55	* reset the device on the One Wire interface
	56	* on the hardware
	57	*/
	58	static u8 mxc_w1_ds2_reset_bus(void *data)
	59	{
	60	u8 reg_val;
	61	unsigned int timeout_cnt = 0;
	62	struct mxc_w1_device *dev = data;
	63
	64	__raw_writeb(0x80, (dev->regs + MXC_W1_CONTROL));
65
66	while (1) {
67	reg_val = __raw_readb(dev->regs + MXC_W1_CONTROL);
68
69	if (((reg_val >> 7) & 0x1) == 0 \|\|
70	timeout_cnt > MXC_W1_RESET_TIMEOUT)
71	break;
72	else
73	timeout_cnt++;
74
75	udelay(100);
76	}
77	return (reg_val >> 7) & 0x1;
78	}
79
80	/*
81	* this is the low level routine to read/write a bit on the One Wire
82	* interface on the hardware. It does write 0 if parameter bit is set
83	* to 0, otherwise a write 1/read.
84	*/
85	static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
86	{
87	struct mxc_w1_device *mdev = data;
88	void __iomem *ctrl_addr = mdev->regs + MXC_W1_CONTROL;
89	unsigned int timeout_cnt = 400; /* Takes max. 120us according to
90	* datasheet.
91	*/
92
93	__raw_writeb((1 << (5 - bit)), ctrl_addr);
94
95	while (timeout_cnt--) {
96	if (!((__raw_readb(ctrl_addr) >> (5 - bit)) & 0x1))
97	break;
98
99	udelay(1);
100	}
101
102	return ((__raw_readb(ctrl_addr)) >> 3) & 0x1;
103	}
104
582ef52a	105	static int __devinit mxc_w1_probe(struct platform_device *pdev)
a5fd9139 SH	106	{
	107	struct mxc_w1_device *mdev;
	108	struct resource *res;
	109	int err = 0;
	110
	111	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	112	if (!res)
	113	return -ENODEV;
	114
	115	mdev = kzalloc(sizeof(struct mxc_w1_device), GFP_KERNEL);
	116	if (!mdev)
	117	return -ENOMEM;
	118
e65fb009	119	mdev->clk = clk_get(&pdev->dev, "owire");
a5fd9139 SH	120	if (!mdev->clk) {
	121	err = -ENODEV;
	122	goto failed_clk;
	123	}
	124
	125	mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1;
	126
	127	res = request_mem_region(res->start, resource_size(res),
	128	"mxc_w1");
	129	if (!res) {
	130	err = -EBUSY;
	131	goto failed_req;
	132	}
	133
	134	mdev->regs = ioremap(res->start, resource_size(res));
	135	if (!mdev->regs) {
	136	printk(KERN_ERR "Cannot map frame buffer registers\n");
	137	goto failed_ioremap;
	138	}
	139
	140	clk_enable(mdev->clk);
	141	__raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER);
	142
	143	mdev->bus_master.data = mdev;
	144	mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus;
	145	mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit;
	146
	147	err = w1_add_master_device(&mdev->bus_master);
	148
	149	if (err)
	150	goto failed_add;
	151
	152	platform_set_drvdata(pdev, mdev);
	153	return 0;
	154
	155	failed_add:
	156	iounmap(mdev->regs);
	157	failed_ioremap:
	158	release_mem_region(res->start, resource_size(res));
	159	failed_req:
	160	clk_put(mdev->clk);
	161	failed_clk:
	162	kfree(mdev);
	163	return err;
	164	}
	165
	166	/*
	167	* disassociate the w1 device from the driver
	168	*/
582ef52a	169	static int __devexit mxc_w1_remove(struct platform_device *pdev)
a5fd9139 SH	170	{
	171	struct mxc_w1_device *mdev = platform_get_drvdata(pdev);
	172	struct resource *res;
	173
	174	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	175
	176	w1_remove_master_device(&mdev->bus_master);
	177
	178	iounmap(mdev->regs);
	179	release_mem_region(res->start, resource_size(res));
	180	clk_disable(mdev->clk);
	181	clk_put(mdev->clk);
	182
	183	platform_set_drvdata(pdev, NULL);
	184
	185	return 0;
	186	}
	187
	188	static struct platform_driver mxc_w1_driver = {
	189	.driver = {
	190	.name = "mxc_w1",
	191	},
	192	.probe = mxc_w1_probe,
	193	.remove = mxc_w1_remove,
	194	};
	195
	196	static int __init mxc_w1_init(void)
	197	{
	198	return platform_driver_register(&mxc_w1_driver);
	199	}
	200
	201	static void mxc_w1_exit(void)
	202	{
	203	platform_driver_unregister(&mxc_w1_driver);
	204	}
	205
	206	module_init(mxc_w1_init);
	207	module_exit(mxc_w1_exit);
	208
	209	MODULE_LICENSE("GPL");
	210	MODULE_AUTHOR("Freescale Semiconductors Inc");
	211	MODULE_DESCRIPTION("Driver for One-Wire on MXC");