1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Janz MODULbus VMOD-TTL GPIO Driver |
4 | * |
5 | * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu> |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/module.h> |
10 | #include <linux/init.h> |
11 | #include <linux/interrupt.h> |
12 | #include <linux/delay.h> |
13 | #include <linux/platform_device.h> |
14 | #include <linux/io.h> |
15 | #include <linux/gpio/driver.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/bitops.h> |
18 | |
19 | #include <linux/mfd/janz.h> |
20 | |
21 | #define DRV_NAME "janz-ttl" |
22 | |
23 | #define PORTA_DIRECTION 0x23 |
24 | #define PORTB_DIRECTION 0x2B |
25 | #define PORTC_DIRECTION 0x06 |
26 | #define PORTA_IOCTL 0x24 |
27 | #define PORTB_IOCTL 0x2C |
28 | #define PORTC_IOCTL 0x07 |
29 | |
30 | #define MASTER_INT_CTL 0x00 |
31 | #define MASTER_CONF_CTL 0x01 |
32 | |
33 | #define CONF_PAE BIT(2) |
34 | #define CONF_PBE BIT(7) |
35 | #define CONF_PCE BIT(4) |
36 | |
37 | struct ttl_control_regs { |
38 | __be16 portc; |
39 | __be16 portb; |
40 | __be16 porta; |
41 | __be16 control; |
42 | }; |
43 | |
44 | struct ttl_module { |
45 | struct gpio_chip gpio; |
46 | |
47 | /* base address of registers */ |
48 | struct ttl_control_regs __iomem *regs; |
49 | |
50 | u8 portc_shadow; |
51 | u8 portb_shadow; |
52 | u8 porta_shadow; |
53 | |
54 | spinlock_t lock; |
55 | }; |
56 | |
57 | static int ttl_get_value(struct gpio_chip *gpio, unsigned offset) |
58 | { |
59 | struct ttl_module *mod = dev_get_drvdata(dev: gpio->parent); |
60 | u8 *shadow; |
61 | int ret; |
62 | |
63 | if (offset < 8) { |
64 | shadow = &mod->porta_shadow; |
65 | } else if (offset < 16) { |
66 | shadow = &mod->portb_shadow; |
67 | offset -= 8; |
68 | } else { |
69 | shadow = &mod->portc_shadow; |
70 | offset -= 16; |
71 | } |
72 | |
73 | spin_lock(lock: &mod->lock); |
74 | ret = *shadow & BIT(offset); |
75 | spin_unlock(lock: &mod->lock); |
76 | return !!ret; |
77 | } |
78 | |
79 | static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value) |
80 | { |
81 | struct ttl_module *mod = dev_get_drvdata(dev: gpio->parent); |
82 | void __iomem *port; |
83 | u8 *shadow; |
84 | |
85 | if (offset < 8) { |
86 | port = &mod->regs->porta; |
87 | shadow = &mod->porta_shadow; |
88 | } else if (offset < 16) { |
89 | port = &mod->regs->portb; |
90 | shadow = &mod->portb_shadow; |
91 | offset -= 8; |
92 | } else { |
93 | port = &mod->regs->portc; |
94 | shadow = &mod->portc_shadow; |
95 | offset -= 16; |
96 | } |
97 | |
98 | spin_lock(lock: &mod->lock); |
99 | if (value) |
100 | *shadow |= BIT(offset); |
101 | else |
102 | *shadow &= ~BIT(offset); |
103 | |
104 | iowrite16be(*shadow, port); |
105 | spin_unlock(lock: &mod->lock); |
106 | } |
107 | |
108 | static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val) |
109 | { |
110 | iowrite16be(reg, &mod->regs->control); |
111 | iowrite16be(val, &mod->regs->control); |
112 | } |
113 | |
114 | static void ttl_setup_device(struct ttl_module *mod) |
115 | { |
116 | /* reset the device to a known state */ |
117 | iowrite16be(0x0000, &mod->regs->control); |
118 | iowrite16be(0x0001, &mod->regs->control); |
119 | iowrite16be(0x0000, &mod->regs->control); |
120 | |
121 | /* put all ports in open-drain mode */ |
122 | ttl_write_reg(mod, PORTA_IOCTL, val: 0x00ff); |
123 | ttl_write_reg(mod, PORTB_IOCTL, val: 0x00ff); |
124 | ttl_write_reg(mod, PORTC_IOCTL, val: 0x000f); |
125 | |
126 | /* set all ports as outputs */ |
127 | ttl_write_reg(mod, PORTA_DIRECTION, val: 0x0000); |
128 | ttl_write_reg(mod, PORTB_DIRECTION, val: 0x0000); |
129 | ttl_write_reg(mod, PORTC_DIRECTION, val: 0x0000); |
130 | |
131 | /* set all ports to drive zeroes */ |
132 | iowrite16be(0x0000, &mod->regs->porta); |
133 | iowrite16be(0x0000, &mod->regs->portb); |
134 | iowrite16be(0x0000, &mod->regs->portc); |
135 | |
136 | /* enable all ports */ |
137 | ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE); |
138 | } |
139 | |
140 | static int ttl_probe(struct platform_device *pdev) |
141 | { |
142 | struct janz_platform_data *pdata; |
143 | struct ttl_module *mod; |
144 | struct gpio_chip *gpio; |
145 | int ret; |
146 | |
147 | pdata = dev_get_platdata(dev: &pdev->dev); |
148 | if (!pdata) { |
149 | dev_err(&pdev->dev, "no platform data\n" ); |
150 | return -ENXIO; |
151 | } |
152 | |
153 | mod = devm_kzalloc(dev: &pdev->dev, size: sizeof(*mod), GFP_KERNEL); |
154 | if (!mod) |
155 | return -ENOMEM; |
156 | |
157 | platform_set_drvdata(pdev, data: mod); |
158 | spin_lock_init(&mod->lock); |
159 | |
160 | /* get access to the MODULbus registers for this module */ |
161 | mod->regs = devm_platform_ioremap_resource(pdev, index: 0); |
162 | if (IS_ERR(ptr: mod->regs)) |
163 | return PTR_ERR(ptr: mod->regs); |
164 | |
165 | ttl_setup_device(mod); |
166 | |
167 | /* Initialize the GPIO data structures */ |
168 | gpio = &mod->gpio; |
169 | gpio->parent = &pdev->dev; |
170 | gpio->label = pdev->name; |
171 | gpio->get = ttl_get_value; |
172 | gpio->set = ttl_set_value; |
173 | gpio->owner = THIS_MODULE; |
174 | |
175 | /* request dynamic allocation */ |
176 | gpio->base = -1; |
177 | gpio->ngpio = 20; |
178 | |
179 | ret = devm_gpiochip_add_data(&pdev->dev, gpio, NULL); |
180 | if (ret) { |
181 | dev_err(&pdev->dev, "unable to add GPIO chip\n" ); |
182 | return ret; |
183 | } |
184 | |
185 | return 0; |
186 | } |
187 | |
188 | static struct platform_driver ttl_driver = { |
189 | .driver = { |
190 | .name = DRV_NAME, |
191 | }, |
192 | .probe = ttl_probe, |
193 | }; |
194 | |
195 | module_platform_driver(ttl_driver); |
196 | |
197 | MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>" ); |
198 | MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver" ); |
199 | MODULE_LICENSE("GPL" ); |
200 | MODULE_ALIAS("platform:janz-ttl" ); |
201 | |