2 * Janz MODULbus VMOD-TTL GPIO Driver
4 * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
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.
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>
19 #include <linux/gpio.h>
20 #include <linux/slab.h>
22 #include <linux/mfd/janz.h>
24 #define DRV_NAME "janz-ttl"
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
33 #define MASTER_INT_CTL 0x00
34 #define MASTER_CONF_CTL 0x01
36 #define CONF_PAE (1 << 2)
37 #define CONF_PBE (1 << 7)
38 #define CONF_PCE (1 << 4)
40 struct ttl_control_regs {
48 struct gpio_chip gpio;
50 /* base address of registers */
51 struct ttl_control_regs __iomem *regs;
60 static int ttl_get_value(struct gpio_chip *gpio, unsigned offset)
62 struct ttl_module *mod = dev_get_drvdata(gpio->dev);
67 shadow = &mod->porta_shadow;
68 } else if (offset < 16) {
69 shadow = &mod->portb_shadow;
72 shadow = &mod->portc_shadow;
76 spin_lock(&mod->lock);
77 ret = *shadow & (1 << offset);
78 spin_unlock(&mod->lock);
82 static void ttl_set_value(struct gpio_chip *gpio, unsigned offset, int value)
84 struct ttl_module *mod = dev_get_drvdata(gpio->dev);
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;
96 port = &mod->regs->portc;
97 shadow = &mod->portc_shadow;
101 spin_lock(&mod->lock);
103 *shadow |= (1 << offset);
105 *shadow &= ~(1 << offset);
107 iowrite16be(*shadow, port);
108 spin_unlock(&mod->lock);
111 static void ttl_write_reg(struct ttl_module *mod, u8 reg, u16 val)
113 iowrite16be(reg, &mod->regs->control);
114 iowrite16be(val, &mod->regs->control);
117 static void ttl_setup_device(struct ttl_module *mod)
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);
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);
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);
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);
139 /* enable all ports */
140 ttl_write_reg(mod, MASTER_CONF_CTL, CONF_PAE | CONF_PBE | CONF_PCE);
143 static int ttl_probe(struct platform_device *pdev)
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;
152 pdata = dev_get_platdata(&pdev->dev);
154 dev_err(dev, "no platform data\n");
158 mod = devm_kzalloc(dev, sizeof(*mod), GFP_KERNEL);
162 platform_set_drvdata(pdev, mod);
163 spin_lock_init(&mod->lock);
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);
171 ttl_setup_device(mod);
173 /* Initialize the GPIO data structures */
175 gpio->dev = &pdev->dev;
176 gpio->label = pdev->name;
177 gpio->get = ttl_get_value;
178 gpio->set = ttl_set_value;
179 gpio->owner = THIS_MODULE;
181 /* request dynamic allocation */
185 ret = gpiochip_add(gpio);
187 dev_err(dev, "unable to add GPIO chip\n");
194 static int ttl_remove(struct platform_device *pdev)
196 struct ttl_module *mod = platform_get_drvdata(pdev);
198 gpiochip_remove(&mod->gpio);
203 static struct platform_driver ttl_driver = {
208 .remove = ttl_remove,
211 module_platform_driver(ttl_driver);
213 MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
214 MODULE_DESCRIPTION("Janz MODULbus VMOD-TTL Driver");
215 MODULE_LICENSE("GPL");
216 MODULE_ALIAS("platform:janz-ttl");