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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> | |
1c947b7f | 19 | #include <linux/gpio/driver.h> |
800e69fb | 20 | #include <linux/slab.h> |
96d0d03d | 21 | #include <linux/bitops.h> |
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22 | |
23 | #include <linux/mfd/janz.h> | |
24 | ||
25 | #define DRV_NAME "janz-ttl" | |
26 | ||
27 | #define PORTA_DIRECTION 0x23 | |
28 | #define PORTB_DIRECTION 0x2B | |
29 | #define PORTC_DIRECTION 0x06 | |
30 | #define PORTA_IOCTL 0x24 | |
31 | #define PORTB_IOCTL 0x2C | |
32 | #define PORTC_IOCTL 0x07 | |
33 | ||
34 | #define MASTER_INT_CTL 0x00 | |
35 | #define MASTER_CONF_CTL 0x01 | |
36 | ||
96d0d03d LW |
37 | #define CONF_PAE BIT(2) |
38 | #define CONF_PBE BIT(7) | |
39 | #define CONF_PCE BIT(4) | |
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40 | |
41 | struct ttl_control_regs { | |
42 | __be16 portc; | |
43 | __be16 portb; | |
44 | __be16 porta; | |
45 | __be16 control; | |
46 | }; | |
47 | ||
48 | struct ttl_module { | |
49 | struct gpio_chip gpio; | |
50 | ||
51 | /* base address of registers */ | |
52 | struct ttl_control_regs __iomem *regs; | |
53 | ||
54 | u8 portc_shadow; | |
55 | u8 portb_shadow; | |
56 | u8 porta_shadow; | |
57 | ||
58 | spinlock_t lock; | |
59 | }; | |
60 | ||
61 | static int ttl_get_value(struct gpio_chip *gpio, unsigned offset) | |
62 | { | |
58383c78 | 63 | struct ttl_module *mod = dev_get_drvdata(gpio->parent); |
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64 | u8 *shadow; |
65 | int ret; | |
66 | ||
67 | if (offset < 8) { | |
68 | shadow = &mod->porta_shadow; | |
69 | } else if (offset < 16) { | |
70 | shadow = &mod->portb_shadow; | |
71 | offset -= 8; | |
72 | } else { | |
73 | shadow = &mod->portc_shadow; | |
74 | offset -= 16; | |
75 | } | |
76 | ||
77 | spin_lock(&mod->lock); | |
96d0d03d | 78 | ret = *shadow & BIT(offset); |
800e69fb | 79 | spin_unlock(&mod->lock); |
828240c2 | 80 | return !!ret; |
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81 | } |
82 | ||
83 | static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value) | |
84 | { | |
58383c78 | 85 | struct ttl_module *mod = dev_get_drvdata(gpio->parent); |
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86 | void __iomem *port; |
87 | u8 *shadow; | |
88 | ||
89 | if (offset < 8) { | |
90 | port = &mod->regs->porta; | |
91 | shadow = &mod->porta_shadow; | |
92 | } else if (offset < 16) { | |
93 | port = &mod->regs->portb; | |
94 | shadow = &mod->portb_shadow; | |
95 | offset -= 8; | |
96 | } else { | |
97 | port = &mod->regs->portc; | |
98 | shadow = &mod->portc_shadow; | |
99 | offset -= 16; | |
100 | } | |
101 | ||
102 | spin_lock(&mod->lock); | |
103 | if (value) | |
96d0d03d | 104 | *shadow |= BIT(offset); |
800e69fb | 105 | else |
96d0d03d | 106 | *shadow &= ~BIT(offset); |
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107 | |
108 | iowrite16be(*shadow, port); | |
109 | spin_unlock(&mod->lock); | |
110 | } | |
111 | ||
3836309d | 112 | static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val) |
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113 | { |
114 | iowrite16be(reg, &mod->regs->control); | |
115 | iowrite16be(val, &mod->regs->control); | |
116 | } | |
117 | ||
3836309d | 118 | static void ttl_setup_device(struct ttl_module *mod) |
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119 | { |
120 | /* reset the device to a known state */ | |
121 | iowrite16be(0x0000, &mod->regs->control); | |
122 | iowrite16be(0x0001, &mod->regs->control); | |
123 | iowrite16be(0x0000, &mod->regs->control); | |
124 | ||
125 | /* put all ports in open-drain mode */ | |
126 | ttl_write_reg(mod, PORTA_IOCTL, 0x00ff); | |
127 | ttl_write_reg(mod, PORTB_IOCTL, 0x00ff); | |
128 | ttl_write_reg(mod, PORTC_IOCTL, 0x000f); | |
129 | ||
130 | /* set all ports as outputs */ | |
131 | ttl_write_reg(mod, PORTA_DIRECTION, 0x0000); | |
132 | ttl_write_reg(mod, PORTB_DIRECTION, 0x0000); | |
133 | ttl_write_reg(mod, PORTC_DIRECTION, 0x0000); | |
134 | ||
135 | /* set all ports to drive zeroes */ | |
136 | iowrite16be(0x0000, &mod->regs->porta); | |
137 | iowrite16be(0x0000, &mod->regs->portb); | |
138 | iowrite16be(0x0000, &mod->regs->portc); | |
139 | ||
140 | /* enable all ports */ | |
141 | ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE); | |
142 | } | |
143 | ||
3836309d | 144 | static int ttl_probe(struct platform_device *pdev) |
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145 | { |
146 | struct janz_platform_data *pdata; | |
147 | struct device *dev = &pdev->dev; | |
148 | struct ttl_module *mod; | |
149 | struct gpio_chip *gpio; | |
150 | struct resource *res; | |
151 | int ret; | |
152 | ||
e56aee18 | 153 | pdata = dev_get_platdata(&pdev->dev); |
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154 | if (!pdata) { |
155 | dev_err(dev, "no platform data\n"); | |
ae28193e | 156 | return -ENXIO; |
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157 | } |
158 | ||
ae28193e | 159 | mod = devm_kzalloc(dev, sizeof(*mod), GFP_KERNEL); |
160 | if (!mod) | |
161 | return -ENOMEM; | |
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162 | |
163 | platform_set_drvdata(pdev, mod); | |
164 | spin_lock_init(&mod->lock); | |
165 | ||
166 | /* get access to the MODULbus registers for this module */ | |
167 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
ae28193e | 168 | mod->regs = devm_ioremap_resource(dev, res); |
169 | if (IS_ERR(mod->regs)) | |
170 | return PTR_ERR(mod->regs); | |
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171 | |
172 | ttl_setup_device(mod); | |
173 | ||
174 | /* Initialize the GPIO data structures */ | |
175 | gpio = &mod->gpio; | |
58383c78 | 176 | gpio->parent = &pdev->dev; |
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177 | gpio->label = pdev->name; |
178 | gpio->get = ttl_get_value; | |
179 | gpio->set = ttl_set_value; | |
180 | gpio->owner = THIS_MODULE; | |
181 | ||
182 | /* request dynamic allocation */ | |
183 | gpio->base = -1; | |
184 | gpio->ngpio = 20; | |
185 | ||
abeb3f40 | 186 | ret = devm_gpiochip_add_data(dev, gpio, NULL); |
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187 | if (ret) { |
188 | dev_err(dev, "unable to add GPIO chip\n"); | |
ae28193e | 189 | return ret; |
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190 | } |
191 | ||
800e69fb | 192 | return 0; |
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193 | } |
194 | ||
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195 | static struct platform_driver ttl_driver = { |
196 | .driver = { | |
197 | .name = DRV_NAME, | |
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198 | }, |
199 | .probe = ttl_probe, | |
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200 | }; |
201 | ||
6f61415e | 202 | module_platform_driver(ttl_driver); |
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203 | |
204 | MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>"); | |
205 | MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver"); | |
206 | MODULE_LICENSE("GPL"); | |
207 | MODULE_ALIAS("platform:janz-ttl"); |