1/*
2 *  i2c_pca_platform.c
3 *
4 *  Platform driver for the PCA9564 I2C controller.
5 *
6 *  Copyright (C) 2008 Pengutronix
7 *
8 *  This program is free software; you can redistribute it and/or modify
9 *  it under the terms of the GNU General Public License version 2 as
10 *  published by the Free Software Foundation.
11
12 */
13#include <linux/kernel.h>
14#include <linux/module.h>
15#include <linux/slab.h>
16#include <linux/delay.h>
17#include <linux/jiffies.h>
18#include <linux/errno.h>
19#include <linux/i2c.h>
20#include <linux/interrupt.h>
21#include <linux/platform_device.h>
22#include <linux/i2c-algo-pca.h>
23#include <linux/i2c-pca-platform.h>
24#include <linux/gpio.h>
25#include <linux/io.h>
26
27#include <asm/irq.h>
28
29struct i2c_pca_pf_data {
30	void __iomem			*reg_base;
31	int				irq;	/* if 0, use polling */
32	int				gpio;
33	wait_queue_head_t		wait;
34	struct i2c_adapter		adap;
35	struct i2c_algo_pca_data	algo_data;
36	unsigned long			io_base;
37	unsigned long			io_size;
38};
39
40/* Read/Write functions for different register alignments */
41
42static int i2c_pca_pf_readbyte8(void *pd, int reg)
43{
44	struct i2c_pca_pf_data *i2c = pd;
45	return ioread8(i2c->reg_base + reg);
46}
47
48static int i2c_pca_pf_readbyte16(void *pd, int reg)
49{
50	struct i2c_pca_pf_data *i2c = pd;
51	return ioread8(i2c->reg_base + reg * 2);
52}
53
54static int i2c_pca_pf_readbyte32(void *pd, int reg)
55{
56	struct i2c_pca_pf_data *i2c = pd;
57	return ioread8(i2c->reg_base + reg * 4);
58}
59
60static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
61{
62	struct i2c_pca_pf_data *i2c = pd;
63	iowrite8(val, i2c->reg_base + reg);
64}
65
66static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
67{
68	struct i2c_pca_pf_data *i2c = pd;
69	iowrite8(val, i2c->reg_base + reg * 2);
70}
71
72static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
73{
74	struct i2c_pca_pf_data *i2c = pd;
75	iowrite8(val, i2c->reg_base + reg * 4);
76}
77
78
79static int i2c_pca_pf_waitforcompletion(void *pd)
80{
81	struct i2c_pca_pf_data *i2c = pd;
82	unsigned long timeout;
83	long ret;
84
85	if (i2c->irq) {
86		ret = wait_event_timeout(i2c->wait,
87			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
88			& I2C_PCA_CON_SI, i2c->adap.timeout);
89	} else {
90		/* Do polling */
91		timeout = jiffies + i2c->adap.timeout;
92		do {
93			ret = time_before(jiffies, timeout);
94			if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
95					& I2C_PCA_CON_SI)
96				break;
97			udelay(100);
98		} while (ret);
99	}
100
101	return ret > 0;
102}
103
104static void i2c_pca_pf_dummyreset(void *pd)
105{
106	struct i2c_pca_pf_data *i2c = pd;
107	printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!\n",
108		i2c->adap.name);
109}
110
111static void i2c_pca_pf_resetchip(void *pd)
112{
113	struct i2c_pca_pf_data *i2c = pd;
114
115	gpio_set_value(i2c->gpio, 0);
116	ndelay(100);
117	gpio_set_value(i2c->gpio, 1);
118}
119
120static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
121{
122	struct i2c_pca_pf_data *i2c = dev_id;
123
124	if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
125		return IRQ_NONE;
126
127	wake_up(&i2c->wait);
128
129	return IRQ_HANDLED;
130}
131
132
133static int i2c_pca_pf_probe(struct platform_device *pdev)
134{
135	struct i2c_pca_pf_data *i2c;
136	struct resource *res;
137	struct i2c_pca9564_pf_platform_data *platform_data =
138				dev_get_platdata(&pdev->dev);
139	int ret = 0;
140	int irq;
141
142	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
143	irq = platform_get_irq(pdev, 0);
144	/* If irq is 0, we do polling. */
145
146	if (res == NULL) {
147		ret = -ENODEV;
148		goto e_print;
149	}
150
151	if (!request_mem_region(res->start, resource_size(res), res->name)) {
152		ret = -ENOMEM;
153		goto e_print;
154	}
155
156	i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
157	if (!i2c) {
158		ret = -ENOMEM;
159		goto e_alloc;
160	}
161
162	init_waitqueue_head(&i2c->wait);
163
164	i2c->reg_base = ioremap(res->start, resource_size(res));
165	if (!i2c->reg_base) {
166		ret = -ENOMEM;
167		goto e_remap;
168	}
169	i2c->io_base = res->start;
170	i2c->io_size = resource_size(res);
171	i2c->irq = irq;
172
173	i2c->adap.nr = pdev->id;
174	i2c->adap.owner = THIS_MODULE;
175	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
176		 "PCA9564/PCA9665 at 0x%08lx",
177		 (unsigned long) res->start);
178	i2c->adap.algo_data = &i2c->algo_data;
179	i2c->adap.dev.parent = &pdev->dev;
180
181	if (platform_data) {
182		i2c->adap.timeout = platform_data->timeout;
183		i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
184		i2c->gpio = platform_data->gpio;
185	} else {
186		i2c->adap.timeout = HZ;
187		i2c->algo_data.i2c_clock = 59000;
188		i2c->gpio = -1;
189	}
190
191	i2c->algo_data.data = i2c;
192	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
193	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
194
195	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
196	case IORESOURCE_MEM_32BIT:
197		i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
198		i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
199		break;
200	case IORESOURCE_MEM_16BIT:
201		i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
202		i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
203		break;
204	case IORESOURCE_MEM_8BIT:
205	default:
206		i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
207		i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
208		break;
209	}
210
211	/* Use gpio_is_valid() when in mainline */
212	if (i2c->gpio > -1) {
213		ret = gpio_request(i2c->gpio, i2c->adap.name);
214		if (ret == 0) {
215			gpio_direction_output(i2c->gpio, 1);
216			i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
217		} else {
218			printk(KERN_WARNING "%s: Registering gpio failed!\n",
219				i2c->adap.name);
220			i2c->gpio = ret;
221		}
222	}
223
224	if (irq) {
225		ret = request_irq(irq, i2c_pca_pf_handler,
226			IRQF_TRIGGER_FALLING, pdev->name, i2c);
227		if (ret)
228			goto e_reqirq;
229	}
230
231	if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
232		ret = -ENODEV;
233		goto e_adapt;
234	}
235
236	platform_set_drvdata(pdev, i2c);
237
238	printk(KERN_INFO "%s registered.\n", i2c->adap.name);
239
240	return 0;
241
242e_adapt:
243	if (irq)
244		free_irq(irq, i2c);
245e_reqirq:
246	if (i2c->gpio > -1)
247		gpio_free(i2c->gpio);
248
249	iounmap(i2c->reg_base);
250e_remap:
251	kfree(i2c);
252e_alloc:
253	release_mem_region(res->start, resource_size(res));
254e_print:
255	printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
256	return ret;
257}
258
259static int i2c_pca_pf_remove(struct platform_device *pdev)
260{
261	struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
262
263	i2c_del_adapter(&i2c->adap);
264
265	if (i2c->irq)
266		free_irq(i2c->irq, i2c);
267
268	if (i2c->gpio > -1)
269		gpio_free(i2c->gpio);
270
271	iounmap(i2c->reg_base);
272	release_mem_region(i2c->io_base, i2c->io_size);
273	kfree(i2c);
274
275	return 0;
276}
277
278static struct platform_driver i2c_pca_pf_driver = {
279	.probe = i2c_pca_pf_probe,
280	.remove = i2c_pca_pf_remove,
281	.driver = {
282		.name = "i2c-pca-platform",
283	},
284};
285
286module_platform_driver(i2c_pca_pf_driver);
287
288MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
289MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
290MODULE_LICENSE("GPL");
291