[go: nahoru, domu]
1/*
2 * Janz MODULbus VMOD-TTL GPIO Driver
3 *
4 * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/interrupt.h>
16#include <linux/delay.h>
17#include <linux/platform_device.h>
18#include <linux/io.h>
19#include <linux/gpio.h>
20#include <linux/slab.h>
21
22#include <linux/mfd/janz.h>
23
24#define DRV_NAME "janz-ttl"
25
26#define PORTA_DIRECTION		0x23
27#define PORTB_DIRECTION		0x2B
28#define PORTC_DIRECTION		0x06
29#define PORTA_IOCTL		0x24
30#define PORTB_IOCTL		0x2C
31#define PORTC_IOCTL		0x07
32
33#define MASTER_INT_CTL		0x00
34#define MASTER_CONF_CTL		0x01
35
36#define CONF_PAE		(1 << 2)
37#define CONF_PBE		(1 << 7)
38#define CONF_PCE		(1 << 4)
39
40struct ttl_control_regs {
41	__be16 portc;
42	__be16 portb;
43	__be16 porta;
44	__be16 control;
45};
46
47struct ttl_module {
48	struct gpio_chip gpio;
49
50	/* base address of registers */
51	struct ttl_control_regs __iomem *regs;
52
53	u8 portc_shadow;
54	u8 portb_shadow;
55	u8 porta_shadow;
56
57	spinlock_t lock;
58};
59
60static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
61{
62	struct ttl_module *mod = dev_get_drvdata(gpio->dev);
63	u8 *shadow;
64	int ret;
65
66	if (offset < 8) {
67		shadow = &mod->porta_shadow;
68	} else if (offset < 16) {
69		shadow = &mod->portb_shadow;
70		offset -= 8;
71	} else {
72		shadow = &mod->portc_shadow;
73		offset -= 16;
74	}
75
76	spin_lock(&mod->lock);
77	ret = *shadow & (1 << offset);
78	spin_unlock(&mod->lock);
79	return ret;
80}
81
82static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
83{
84	struct ttl_module *mod = dev_get_drvdata(gpio->dev);
85	void __iomem *port;
86	u8 *shadow;
87
88	if (offset < 8) {
89		port = &mod->regs->porta;
90		shadow = &mod->porta_shadow;
91	} else if (offset < 16) {
92		port = &mod->regs->portb;
93		shadow = &mod->portb_shadow;
94		offset -= 8;
95	} else {
96		port = &mod->regs->portc;
97		shadow = &mod->portc_shadow;
98		offset -= 16;
99	}
100
101	spin_lock(&mod->lock);
102	if (value)
103		*shadow |= (1 << offset);
104	else
105		*shadow &= ~(1 << offset);
106
107	iowrite16be(*shadow, port);
108	spin_unlock(&mod->lock);
109}
110
111static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
112{
113	iowrite16be(reg, &mod->regs->control);
114	iowrite16be(val, &mod->regs->control);
115}
116
117static void ttl_setup_device(struct ttl_module *mod)
118{
119	/* reset the device to a known state */
120	iowrite16be(0x0000, &mod->regs->control);
121	iowrite16be(0x0001, &mod->regs->control);
122	iowrite16be(0x0000, &mod->regs->control);
123
124	/* put all ports in open-drain mode */
125	ttl_write_reg(mod, PORTA_IOCTL, 0x00ff);
126	ttl_write_reg(mod, PORTB_IOCTL, 0x00ff);
127	ttl_write_reg(mod, PORTC_IOCTL, 0x000f);
128
129	/* set all ports as outputs */
130	ttl_write_reg(mod, PORTA_DIRECTION, 0x0000);
131	ttl_write_reg(mod, PORTB_DIRECTION, 0x0000);
132	ttl_write_reg(mod, PORTC_DIRECTION, 0x0000);
133
134	/* set all ports to drive zeroes */
135	iowrite16be(0x0000, &mod->regs->porta);
136	iowrite16be(0x0000, &mod->regs->portb);
137	iowrite16be(0x0000, &mod->regs->portc);
138
139	/* enable all ports */
140	ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE);
141}
142
143static int ttl_probe(struct platform_device *pdev)
144{
145	struct janz_platform_data *pdata;
146	struct device *dev = &pdev->dev;
147	struct ttl_module *mod;
148	struct gpio_chip *gpio;
149	struct resource *res;
150	int ret;
151
152	pdata = dev_get_platdata(&pdev->dev);
153	if (!pdata) {
154		dev_err(dev, "no platform data\n");
155		return -ENXIO;
156	}
157
158	mod = devm_kzalloc(dev, sizeof(*mod), GFP_KERNEL);
159	if (!mod)
160		return -ENOMEM;
161
162	platform_set_drvdata(pdev, mod);
163	spin_lock_init(&mod->lock);
164
165	/* get access to the MODULbus registers for this module */
166	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
167	mod->regs = devm_ioremap_resource(dev, res);
168	if (IS_ERR(mod->regs))
169		return PTR_ERR(mod->regs);
170
171	ttl_setup_device(mod);
172
173	/* Initialize the GPIO data structures */
174	gpio = &mod->gpio;
175	gpio->dev = &pdev->dev;
176	gpio->label = pdev->name;
177	gpio->get = ttl_get_value;
178	gpio->set = ttl_set_value;
179	gpio->owner = THIS_MODULE;
180
181	/* request dynamic allocation */
182	gpio->base = -1;
183	gpio->ngpio = 20;
184
185	ret = gpiochip_add(gpio);
186	if (ret) {
187		dev_err(dev, "unable to add GPIO chip\n");
188		return ret;
189	}
190
191	return 0;
192}
193
194static int ttl_remove(struct platform_device *pdev)
195{
196	struct ttl_module *mod = platform_get_drvdata(pdev);
197
198	gpiochip_remove(&mod->gpio);
199
200	return 0;
201}
202
203static struct platform_driver ttl_driver = {
204	.driver		= {
205		.name	= DRV_NAME,
206		.owner	= THIS_MODULE,
207	},
208	.probe		= ttl_probe,
209	.remove		= ttl_remove,
210};
211
212module_platform_driver(ttl_driver);
213
214MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
215MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
216MODULE_LICENSE("GPL");
217MODULE_ALIAS("platform:janz-ttl");
218