summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-puv3.c
blob: 287088b8c4c834734a0d6b43924f225c8e4a751e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
/*
 * I2C driver for PKUnity-v3 SoC
 * Code specific to PKUnity SoC and UniCore ISA
 *
 *	Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
 *	Copyright (C) 2001-2010 Guan Xuetao
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <mach/hardware.h>

/*
 * Poll the i2c status register until the specified bit is set.
 * Returns 0 if timed out (100 msec).
 */
static short poll_status(unsigned long bit)
{
	int loop_cntr = 1000;

	if (bit & I2C_STATUS_TFNF) {
		do {
			udelay(10);
		} while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
	} else {
		/* RXRDY handler */
		do {
			if (readl(I2C_TAR) == I2C_TAR_EEPROM)
				msleep(20);
			else
				udelay(10);
		} while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
	}

	return (loop_cntr > 0);
}

static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
{
	int i2c_reg = *buf;

	/* Read data */
	while (length--) {
		if (!poll_status(I2C_STATUS_TFNF)) {
			dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
			return -ETIMEDOUT;
		}

		/* send addr */
		writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);

		/* get ready to next write */
		i2c_reg++;

		/* send read CMD */
		writel(I2C_DATACMD_READ, I2C_DATACMD);

		/* wait until the Rx FIFO have available */
		if (!poll_status(I2C_STATUS_RFNE)) {
			dev_dbg(&adap->dev, "RXRDY timeout\n");
			return -ETIMEDOUT;
		}

		/* read the data to buf */
		*buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
		buf++;
	}

	return 0;
}

static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
{
	int i2c_reg = *buf;

	/* Do nothing but storing the reg_num to a static variable */
	if (i2c_reg == -1) {
		printk(KERN_WARNING "Error i2c reg\n");
		return -ETIMEDOUT;
	}

	if (length == 1)
		return 0;

	buf++;
	length--;
	while (length--) {
		/* send addr */
		writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);

		/* send write CMD */
		writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);

		/* wait until the Rx FIFO have available */
		msleep(20);

		/* read the data to buf */
		i2c_reg++;
		buf++;
	}

	return 0;
}

/*
 * Generic i2c master transfer entrypoint.
 *
 */
static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
		int num)
{
	int i, ret;
	unsigned char swap;

	/* Disable i2c */
	writel(I2C_ENABLE_DISABLE, I2C_ENABLE);

	/* Set the work mode and speed*/
	writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);

	writel(pmsg->addr, I2C_TAR);

	/* Enable i2c */
	writel(I2C_ENABLE_ENABLE, I2C_ENABLE);

	dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);

	for (i = 0; i < num; i++) {
		dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
			pmsg->flags & I2C_M_RD ? "read" : "writ",
			pmsg->len, pmsg->len > 1 ? "s" : "",
			pmsg->flags & I2C_M_RD ? "from" : "to",	pmsg->addr);

		if (pmsg->len && pmsg->buf) {	/* sanity check */
			if (pmsg->flags & I2C_M_RD)
				ret = xfer_read(adap, pmsg->buf, pmsg->len);
			else
				ret = xfer_write(adap, pmsg->buf, pmsg->len);

			if (ret)
				return ret;

		}
		dev_dbg(&adap->dev, "transfer complete\n");
		pmsg++;		/* next message */
	}

	/* XXX: fixup be16_to_cpu in bq27x00_battery.c */
	if (pmsg->addr == I2C_TAR_PWIC) {
		swap = pmsg->buf[0];
		pmsg->buf[0] = pmsg->buf[1];
		pmsg->buf[1] = swap;
	}

	return i;
}

/*
 * Return list of supported functionality.
 */
static u32 puv3_i2c_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

static const struct i2c_algorithm puv3_i2c_algorithm = {
	.master_xfer	= puv3_i2c_xfer,
	.functionality	= puv3_i2c_func,
};

/*
 * Main initialization routine.
 */
static int puv3_i2c_probe(struct platform_device *pdev)
{
	struct i2c_adapter *adapter;
	struct resource *mem;
	int rc;

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

	if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
		return -EBUSY;

	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
	if (adapter == NULL) {
		dev_err(&pdev->dev, "can't allocate interface!\n");
		rc = -ENOMEM;
		goto fail_nomem;
	}
	snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
			mem->start);
	adapter->algo = &puv3_i2c_algorithm;
	adapter->class = I2C_CLASS_HWMON;
	adapter->dev.parent = &pdev->dev;

	platform_set_drvdata(pdev, adapter);

	adapter->nr = pdev->id;
	rc = i2c_add_numbered_adapter(adapter);
	if (rc)
		goto fail_add_adapter;

	dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
	return 0;

fail_add_adapter:
	kfree(adapter);
fail_nomem:
	release_mem_region(mem->start, resource_size(mem));

	return rc;
}

static int puv3_i2c_remove(struct platform_device *pdev)
{
	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
	struct resource *mem;

	i2c_del_adapter(adapter);

	put_device(&pdev->dev);

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(mem->start, resource_size(mem));

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int puv3_i2c_suspend(struct device *dev)
{
	int poll_count;
	/* Disable the IIC */
	writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
	for (poll_count = 0; poll_count < 50; poll_count++) {
		if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
			udelay(25);
	}

	return 0;
}

static SIMPLE_DEV_PM_OPS(puv3_i2c_pm, puv3_i2c_suspend, NULL);
#define PUV3_I2C_PM	(&puv3_i2c_pm)

#else
#define PUV3_I2C_PM	NULL
#endif

static struct platform_driver puv3_i2c_driver = {
	.probe		= puv3_i2c_probe,
	.remove		= puv3_i2c_remove,
	.driver		= {
		.name	= "PKUnity-v3-I2C",
		.pm	= PUV3_I2C_PM,
	}
};

module_platform_driver(puv3_i2c_driver);

MODULE_DESCRIPTION("PKUnity v3 I2C driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:puv3_i2c");
OpenPOWER on IntegriCloud