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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
37struct ttl_control_regs {
38 __be16 portc;
39 __be16 portb;
40 __be16 porta;
41 __be16 control;
42};
43
44struct 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
57static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
58{
59 struct ttl_module *mod = dev_get_drvdata(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(&mod->lock);
74 ret = *shadow & BIT(offset);
75 spin_unlock(&mod->lock);
76 return !!ret;
77}
78
79static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
80{
81 struct ttl_module *mod = dev_get_drvdata(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(&mod->lock);
99 if (value)
100 *shadow |= BIT(offset);
101 else
102 *shadow &= ~BIT(offset);
103
104 iowrite16be(*shadow, port);
105 spin_unlock(&mod->lock);
106}
107
108static 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
114static 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, 0x00ff);
123 ttl_write_reg(mod, PORTB_IOCTL, 0x00ff);
124 ttl_write_reg(mod, PORTC_IOCTL, 0x000f);
125
126 /* set all ports as outputs */
127 ttl_write_reg(mod, PORTA_DIRECTION, 0x0000);
128 ttl_write_reg(mod, PORTB_DIRECTION, 0x0000);
129 ttl_write_reg(mod, PORTC_DIRECTION, 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
140static 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(&pdev->dev);
148 if (!pdata) {
149 dev_err(&pdev->dev, "no platform data\n");
150 return -ENXIO;
151 }
152
153 mod = devm_kzalloc(&pdev->dev, sizeof(*mod), GFP_KERNEL);
154 if (!mod)
155 return -ENOMEM;
156
157 platform_set_drvdata(pdev, 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, 0);
162 if (IS_ERR(mod->regs))
163 return PTR_ERR(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
188static struct platform_driver ttl_driver = {
189 .driver = {
190 .name = DRV_NAME,
191 },
192 .probe = ttl_probe,
193};
194
195module_platform_driver(ttl_driver);
196
197MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
198MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
199MODULE_LICENSE("GPL");
200MODULE_ALIAS("platform:janz-ttl");
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->parent);
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->parent);
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->parent = &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 = devm_gpiochip_add_data(dev, gpio, NULL);
186 if (ret) {
187 dev_err(dev, "unable to add GPIO chip\n");
188 return ret;
189 }
190
191 return 0;
192}
193
194static struct platform_driver ttl_driver = {
195 .driver = {
196 .name = DRV_NAME,
197 },
198 .probe = ttl_probe,
199};
200
201module_platform_driver(ttl_driver);
202
203MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
204MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
205MODULE_LICENSE("GPL");
206MODULE_ALIAS("platform:janz-ttl");