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Ira W. Snyder800e69f2010-04-07 10:08:01 +02001/*
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
Bill Pemberton38363092012-11-19 13:22:34 -0500111static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200112{
113 iowrite16be(reg, &mod->regs->control);
114 iowrite16be(val, &mod->regs->control);
115}
116
Bill Pemberton38363092012-11-19 13:22:34 -0500117static void ttl_setup_device(struct ttl_module *mod)
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200118{
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
Bill Pemberton38363092012-11-19 13:22:34 -0500143static int ttl_probe(struct platform_device *pdev)
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200144{
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
Samuel Ortiz3d2bdf72011-04-06 16:02:25 +0200152 pdata = pdev->dev.platform_data;
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200153 if (!pdata) {
154 dev_err(dev, "no platform data\n");
155 ret = -ENXIO;
156 goto out_return;
157 }
158
159 mod = kzalloc(sizeof(*mod), GFP_KERNEL);
160 if (!mod) {
161 dev_err(dev, "unable to allocate private data\n");
162 ret = -ENOMEM;
163 goto out_return;
164 }
165
166 platform_set_drvdata(pdev, mod);
167 spin_lock_init(&mod->lock);
168
169 /* get access to the MODULbus registers for this module */
170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171 if (!res) {
172 dev_err(dev, "MODULbus registers not found\n");
173 ret = -ENODEV;
174 goto out_free_mod;
175 }
176
177 mod->regs = ioremap(res->start, resource_size(res));
178 if (!mod->regs) {
179 dev_err(dev, "MODULbus registers not ioremap\n");
180 ret = -ENOMEM;
181 goto out_free_mod;
182 }
183
184 ttl_setup_device(mod);
185
186 /* Initialize the GPIO data structures */
187 gpio = &mod->gpio;
188 gpio->dev = &pdev->dev;
189 gpio->label = pdev->name;
190 gpio->get = ttl_get_value;
191 gpio->set = ttl_set_value;
192 gpio->owner = THIS_MODULE;
193
194 /* request dynamic allocation */
195 gpio->base = -1;
196 gpio->ngpio = 20;
197
198 ret = gpiochip_add(gpio);
199 if (ret) {
200 dev_err(dev, "unable to add GPIO chip\n");
201 goto out_iounmap_regs;
202 }
203
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200204 return 0;
205
206out_iounmap_regs:
207 iounmap(mod->regs);
208out_free_mod:
209 kfree(mod);
210out_return:
211 return ret;
212}
213
Bill Pemberton206210c2012-11-19 13:25:50 -0500214static int ttl_remove(struct platform_device *pdev)
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200215{
216 struct ttl_module *mod = platform_get_drvdata(pdev);
217 struct device *dev = &pdev->dev;
218 int ret;
219
220 ret = gpiochip_remove(&mod->gpio);
221 if (ret) {
222 dev_err(dev, "unable to remove GPIO chip\n");
223 return ret;
224 }
225
226 iounmap(mod->regs);
227 kfree(mod);
228 return 0;
229}
230
231static struct platform_driver ttl_driver = {
232 .driver = {
233 .name = DRV_NAME,
234 .owner = THIS_MODULE,
235 },
236 .probe = ttl_probe,
Bill Pemberton8283c4f2012-11-19 13:20:08 -0500237 .remove = ttl_remove,
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200238};
239
Mark Brown6f614152011-12-08 00:24:00 +0800240module_platform_driver(ttl_driver);
Ira W. Snyder800e69f2010-04-07 10:08:01 +0200241
242MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
243MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
244MODULE_LICENSE("GPL");
245MODULE_ALIAS("platform:janz-ttl");