aboutsummaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-pca-platform.c
blob: 9d75f51e8f0efe648a22ff3ec33d231b42888167 (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
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
/*
 *  i2c_pca_platform.c
 *
 *  Platform driver for the PCA9564 I2C controller.
 *
 *  Copyright (C) 2008 Pengutronix
 *
 *  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/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/i2c-algo-pca.h>
#include <linux/i2c-pca-platform.h>
#include <linux/gpio.h>

#include <asm/irq.h>
#include <asm/io.h>

#define res_len(r)		((r)->end - (r)->start + 1)

struct i2c_pca_pf_data {
	void __iomem			*reg_base;
	int				irq;	/* if 0, use polling */
	int				gpio;
	wait_queue_head_t		wait;
	struct i2c_adapter		adap;
	struct i2c_algo_pca_data	algo_data;
	unsigned long			io_base;
	unsigned long			io_size;
};

/* Read/Write functions for different register alignments */

static int i2c_pca_pf_readbyte8(void *pd, int reg)
{
	struct i2c_pca_pf_data *i2c = pd;
	return ioread8(i2c->reg_base + reg);
}

static int i2c_pca_pf_readbyte16(void *pd, int reg)
{
	struct i2c_pca_pf_data *i2c = pd;
	return ioread8(i2c->reg_base + reg * 2);
}

static int i2c_pca_pf_readbyte32(void *pd, int reg)
{
	struct i2c_pca_pf_data *i2c = pd;
	return ioread8(i2c->reg_base + reg * 4);
}

static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
{
	struct i2c_pca_pf_data *i2c = pd;
	iowrite8(val, i2c->reg_base + reg);
}

static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
{
	struct i2c_pca_pf_data *i2c = pd;
	iowrite8(val, i2c->reg_base + reg * 2);
}

static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
{
	struct i2c_pca_pf_data *i2c = pd;
	iowrite8(val, i2c->reg_base + reg * 4);
}


static int i2c_pca_pf_waitforcompletion(void *pd)
{
	struct i2c_pca_pf_data *i2c = pd;
	int ret = 0;

	if (i2c->irq) {
		ret = wait_event_interruptible(i2c->wait,
			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
			& I2C_PCA_CON_SI);
	} else {
		/*
		 * Do polling...
		 * XXX: Could get stuck in extreme cases!
		 *      Maybe add timeout, but using irqs is preferred anyhow.
		 */
		while ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
				& I2C_PCA_CON_SI) == 0)
			udelay(100);
	}

	return ret;
}

static void i2c_pca_pf_dummyreset(void *pd)
{
	struct i2c_pca_pf_data *i2c = pd;
	printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n",
		i2c->adap.name);
}

static void i2c_pca_pf_resetchip(void *pd)
{
	struct i2c_pca_pf_data *i2c = pd;

	gpio_set_value(i2c->gpio, 0);
	ndelay(100);
	gpio_set_value(i2c->gpio, 1);
}

static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
{
	struct i2c_pca_pf_data *i2c = dev_id;

	if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
		return IRQ_NONE;

	wake_up_interruptible(&i2c->wait);

	return IRQ_HANDLED;
}


static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
{
	struct i2c_pca_pf_data *i2c;
	struct resource *res;
	struct i2c_pca9564_pf_platform_data *platform_data =
				pdev->dev.platform_data;
	int ret = 0;
	int irq;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irq = platform_get_irq(pdev, 0);
	/* If irq is 0, we do polling. */

	if (res == NULL) {
		ret = -ENODEV;
		goto e_print;
	}

	if (!request_mem_region(res->start, res_len(res), res->name)) {
		ret = -ENOMEM;
		goto e_print;
	}

	i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
	if (!i2c) {
		ret = -ENOMEM;
		goto e_alloc;
	}

	init_waitqueue_head(&i2c->wait);

	i2c->reg_base = ioremap(res->start, res_len(res));
	if (!i2c->reg_base) {
		ret = -EIO;
		goto e_remap;
	}
	i2c->io_base = res->start;
	i2c->io_size = res_len(res);
	i2c->irq = irq;

	i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
	i2c->adap.owner = THIS_MODULE;
	snprintf(i2c->adap.name, sizeof(i2c->adap.name), "PCA9564 at 0x%08lx",
		(unsigned long) res->start);
	i2c->adap.algo_data = &i2c->algo_data;
	i2c->adap.dev.parent = &pdev->dev;
	i2c->adap.timeout = platform_data->timeout;

	i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
	i2c->algo_data.data = i2c;

	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
	case IORESOURCE_MEM_32BIT:
		i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
		i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
		break;
	case IORESOURCE_MEM_16BIT:
		i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
		i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
		break;
	case IORESOURCE_MEM_8BIT:
	default:
		i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
		i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
		break;
	}

	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;

	i2c->gpio = platform_data->gpio;
	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;

	/* Use gpio_is_valid() when in mainline */
	if (i2c->gpio > -1) {
		ret = gpio_request(i2c->gpio, i2c->adap.name);
		if (ret == 0) {
			gpio_direction_output(i2c->gpio, 1);
			i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
		} else {
			printk(KERN_WARNING "%s: Registering gpio failed!\n",
				i2c->adap.name);
			i2c->gpio = ret;
		}
	}

	if (irq) {
		ret = request_irq(irq, i2c_pca_pf_handler,
			IRQF_TRIGGER_FALLING, i2c->adap.name, i2c);
		if (ret)
			goto e_reqirq;
	}

	if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
		ret = -ENODEV;
		goto e_adapt;
	}

	platform_set_drvdata(pdev, i2c);

	printk(KERN_INFO "%s registered.\n", i2c->adap.name);

	return 0;

e_adapt:
	if (irq)
		free_irq(irq, i2c);
e_reqirq:
	if (i2c->gpio > -1)
		gpio_free(i2c->gpio);

	iounmap(i2c->reg_base);
e_remap:
	kfree(i2c);
e_alloc:
	release_mem_region(res->start, res_len(res));
e_print:
	printk(KERN_ERR "Registering PCA9564 FAILED! (%d)\n", ret);
	return ret;
}

static int __devexit i2c_pca_pf_remove(struct platform_device *pdev)
{
	struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
	platform_set_drvdata(pdev, NULL);

	i2c_del_adapter(&i2c->adap);

	if (i2c->irq)
		free_irq(i2c->irq, i2c);

	if (i2c->gpio > -1)
		gpio_free(i2c->gpio);

	iounmap(i2c->reg_base);
	release_mem_region(i2c->io_base, i2c->io_size);
	kfree(i2c);

	return 0;
}

static struct platform_driver i2c_pca_pf_driver = {
	.probe = i2c_pca_pf_probe,
	.remove = __devexit_p(i2c_pca_pf_remove),
	.driver = {
		.name = "i2c-pca-platform",
		.owner = THIS_MODULE,
	},
};

static int __init i2c_pca_pf_init(void)
{
	return platform_driver_register(&i2c_pca_pf_driver);
}

static void __exit i2c_pca_pf_exit(void)
{
	platform_driver_unregister(&i2c_pca_pf_driver);
}

MODULE_AUTHOR("Wolfram Sang <w.sang@pengutronix.de>");
MODULE_DESCRIPTION("I2C-PCA9564 platform driver");
MODULE_LICENSE("GPL");

module_init(i2c_pca_pf_init);
module_exit(i2c_pca_pf_exit);