summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-janz-ttl.c
blob: 365dd040445bdd4a83a3db7263a2936e2542eda3 (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
/*
 * Janz MODULbus VMOD-TTL GPIO Driver
 *
 * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
 *
 * 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include <linux/mfd/janz.h>

#define DRV_NAME "janz-ttl"

#define PORTA_DIRECTION		0x23
#define PORTB_DIRECTION		0x2B
#define PORTC_DIRECTION		0x06
#define PORTA_IOCTL		0x24
#define PORTB_IOCTL		0x2C
#define PORTC_IOCTL		0x07

#define MASTER_INT_CTL		0x00
#define MASTER_CONF_CTL		0x01

#define CONF_PAE		(1 << 2)
#define CONF_PBE		(1 << 7)
#define CONF_PCE		(1 << 4)

struct ttl_control_regs {
	__be16 portc;
	__be16 portb;
	__be16 porta;
	__be16 control;
};

struct ttl_module {
	struct gpio_chip gpio;

	/* base address of registers */
	struct ttl_control_regs __iomem *regs;

	u8 portc_shadow;
	u8 portb_shadow;
	u8 porta_shadow;

	spinlock_t lock;
};

static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
{
	struct ttl_module *mod = dev_get_drvdata(gpio->dev);
	u8 *shadow;
	int ret;

	if (offset < 8) {
		shadow = &mod->porta_shadow;
	} else if (offset < 16) {
		shadow = &mod->portb_shadow;
		offset -= 8;
	} else {
		shadow = &mod->portc_shadow;
		offset -= 16;
	}

	spin_lock(&mod->lock);
	ret = *shadow & (1 << offset);
	spin_unlock(&mod->lock);
	return ret;
}

static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
{
	struct ttl_module *mod = dev_get_drvdata(gpio->dev);
	void __iomem *port;
	u8 *shadow;

	if (offset < 8) {
		port = &mod->regs->porta;
		shadow = &mod->porta_shadow;
	} else if (offset < 16) {
		port = &mod->regs->portb;
		shadow = &mod->portb_shadow;
		offset -= 8;
	} else {
		port = &mod->regs->portc;
		shadow = &mod->portc_shadow;
		offset -= 16;
	}

	spin_lock(&mod->lock);
	if (value)
		*shadow |= (1 << offset);
	else
		*shadow &= ~(1 << offset);

	iowrite16be(*shadow, port);
	spin_unlock(&mod->lock);
}

static void __devinit ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
{
	iowrite16be(reg, &mod->regs->control);
	iowrite16be(val, &mod->regs->control);
}

static void __devinit ttl_setup_device(struct ttl_module *mod)
{
	/* reset the device to a known state */
	iowrite16be(0x0000, &mod->regs->control);
	iowrite16be(0x0001, &mod->regs->control);
	iowrite16be(0x0000, &mod->regs->control);

	/* put all ports in open-drain mode */
	ttl_write_reg(mod, PORTA_IOCTL, 0x00ff);
	ttl_write_reg(mod, PORTB_IOCTL, 0x00ff);
	ttl_write_reg(mod, PORTC_IOCTL, 0x000f);

	/* set all ports as outputs */
	ttl_write_reg(mod, PORTA_DIRECTION, 0x0000);
	ttl_write_reg(mod, PORTB_DIRECTION, 0x0000);
	ttl_write_reg(mod, PORTC_DIRECTION, 0x0000);

	/* set all ports to drive zeroes */
	iowrite16be(0x0000, &mod->regs->porta);
	iowrite16be(0x0000, &mod->regs->portb);
	iowrite16be(0x0000, &mod->regs->portc);

	/* enable all ports */
	ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE);
}

static int __devinit ttl_probe(struct platform_device *pdev)
{
	struct janz_platform_data *pdata;
	struct device *dev = &pdev->dev;
	struct ttl_module *mod;
	struct gpio_chip *gpio;
	struct resource *res;
	int ret;

	pdata = pdev->dev.platform_data;
	if (!pdata) {
		dev_err(dev, "no platform data\n");
		ret = -ENXIO;
		goto out_return;
	}

	mod = kzalloc(sizeof(*mod), GFP_KERNEL);
	if (!mod) {
		dev_err(dev, "unable to allocate private data\n");
		ret = -ENOMEM;
		goto out_return;
	}

	platform_set_drvdata(pdev, mod);
	spin_lock_init(&mod->lock);

	/* get access to the MODULbus registers for this module */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "MODULbus registers not found\n");
		ret = -ENODEV;
		goto out_free_mod;
	}

	mod->regs = ioremap(res->start, resource_size(res));
	if (!mod->regs) {
		dev_err(dev, "MODULbus registers not ioremap\n");
		ret = -ENOMEM;
		goto out_free_mod;
	}

	ttl_setup_device(mod);

	/* Initialize the GPIO data structures */
	gpio = &mod->gpio;
	gpio->dev = &pdev->dev;
	gpio->label = pdev->name;
	gpio->get = ttl_get_value;
	gpio->set = ttl_set_value;
	gpio->owner = THIS_MODULE;

	/* request dynamic allocation */
	gpio->base = -1;
	gpio->ngpio = 20;

	ret = gpiochip_add(gpio);
	if (ret) {
		dev_err(dev, "unable to add GPIO chip\n");
		goto out_iounmap_regs;
	}

	return 0;

out_iounmap_regs:
	iounmap(mod->regs);
out_free_mod:
	kfree(mod);
out_return:
	return ret;
}

static int __devexit ttl_remove(struct platform_device *pdev)
{
	struct ttl_module *mod = platform_get_drvdata(pdev);
	struct device *dev = &pdev->dev;
	int ret;

	ret = gpiochip_remove(&mod->gpio);
	if (ret) {
		dev_err(dev, "unable to remove GPIO chip\n");
		return ret;
	}

	iounmap(mod->regs);
	kfree(mod);
	return 0;
}

static struct platform_driver ttl_driver = {
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},
	.probe		= ttl_probe,
	.remove		= ttl_remove,
};

module_platform_driver(ttl_driver);

MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:janz-ttl");