1/*
2 * RDC321x GPIO driver
3 *
4 * Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
5 * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 *
21 */
22#include <linux/module.h>
23#include <linux/kernel.h>
24#include <linux/init.h>
25#include <linux/spinlock.h>
26#include <linux/platform_device.h>
27#include <linux/pci.h>
28#include <linux/gpio/driver.h>
29#include <linux/mfd/rdc321x.h>
30#include <linux/slab.h>
31
32struct rdc321x_gpio {
33 spinlock_t lock;
34 struct pci_dev *sb_pdev;
35 u32 data_reg[2];
36 int reg1_ctrl_base;
37 int reg1_data_base;
38 int reg2_ctrl_base;
39 int reg2_data_base;
40 struct gpio_chip chip;
41};
42
43/* read GPIO pin */
44static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
45{
46 struct rdc321x_gpio *gpch;
47 u32 value = 0;
48 int reg;
49
50 gpch = gpiochip_get_data(chip);
51 reg = gpio < 32 ? gpch->reg1_data_base : gpch->reg2_data_base;
52
53 spin_lock(&gpch->lock);
54 pci_write_config_dword(gpch->sb_pdev, reg,
55 gpch->data_reg[gpio < 32 ? 0 : 1]);
56 pci_read_config_dword(gpch->sb_pdev, reg, &value);
57 spin_unlock(&gpch->lock);
58
59 return (1 << (gpio & 0x1f)) & value ? 1 : 0;
60}
61
62static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
63 unsigned gpio, int value)
64{
65 struct rdc321x_gpio *gpch;
66 int reg = (gpio < 32) ? 0 : 1;
67
68 gpch = gpiochip_get_data(chip);
69
70 if (value)
71 gpch->data_reg[reg] |= 1 << (gpio & 0x1f);
72 else
73 gpch->data_reg[reg] &= ~(1 << (gpio & 0x1f));
74
75 pci_write_config_dword(gpch->sb_pdev,
76 reg ? gpch->reg2_data_base : gpch->reg1_data_base,
77 gpch->data_reg[reg]);
78}
79
80/* set GPIO pin to value */
81static void rdc_gpio_set_value(struct gpio_chip *chip,
82 unsigned gpio, int value)
83{
84 struct rdc321x_gpio *gpch;
85
86 gpch = gpiochip_get_data(chip);
87 spin_lock(&gpch->lock);
88 rdc_gpio_set_value_impl(chip, gpio, value);
89 spin_unlock(&gpch->lock);
90}
91
92static int rdc_gpio_config(struct gpio_chip *chip,
93 unsigned gpio, int value)
94{
95 struct rdc321x_gpio *gpch;
96 int err;
97 u32 reg;
98
99 gpch = gpiochip_get_data(chip);
100
101 spin_lock(&gpch->lock);
102 err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ?
103 gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, &reg);
104 if (err)
105 goto unlock;
106
107 reg |= 1 << (gpio & 0x1f);
108
109 err = pci_write_config_dword(gpch->sb_pdev, gpio < 32 ?
110 gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, reg);
111 if (err)
112 goto unlock;
113
114 rdc_gpio_set_value_impl(chip, gpio, value);
115
116unlock:
117 spin_unlock(&gpch->lock);
118
119 return err;
120}
121
122/* configure GPIO pin as input */
123static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
124{
125 return rdc_gpio_config(chip, gpio, 1);
126}
127
128/*
129 * Cache the initial value of both GPIO data registers
130 */
131static int rdc321x_gpio_probe(struct platform_device *pdev)
132{
133 int err;
134 struct resource *r;
135 struct rdc321x_gpio *rdc321x_gpio_dev;
136 struct rdc321x_gpio_pdata *pdata;
137
138 pdata = dev_get_platdata(&pdev->dev);
139 if (!pdata) {
140 dev_err(&pdev->dev, "no platform data supplied\n");
141 return -ENODEV;
142 }
143
144 rdc321x_gpio_dev = devm_kzalloc(&pdev->dev, sizeof(struct rdc321x_gpio),
145 GFP_KERNEL);
146 if (!rdc321x_gpio_dev)
147 return -ENOMEM;
148
149 r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg1");
150 if (!r) {
151 dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
152 return -ENODEV;
153 }
154
155 spin_lock_init(&rdc321x_gpio_dev->lock);
156 rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
157 rdc321x_gpio_dev->reg1_ctrl_base = r->start;
158 rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
159
160 r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg2");
161 if (!r) {
162 dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
163 return -ENODEV;
164 }
165
166 rdc321x_gpio_dev->reg2_ctrl_base = r->start;
167 rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
168
169 rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
170 rdc321x_gpio_dev->chip.owner = THIS_MODULE;
171 rdc321x_gpio_dev->chip.direction_input = rdc_gpio_direction_input;
172 rdc321x_gpio_dev->chip.direction_output = rdc_gpio_config;
173 rdc321x_gpio_dev->chip.get = rdc_gpio_get_value;
174 rdc321x_gpio_dev->chip.set = rdc_gpio_set_value;
175 rdc321x_gpio_dev->chip.base = 0;
176 rdc321x_gpio_dev->chip.ngpio = pdata->max_gpios;
177
178 platform_set_drvdata(pdev, rdc321x_gpio_dev);
179
180 /* This might not be, what others (BIOS, bootloader, etc.)
181 wrote to these registers before, but it's a good guess. Still
182 better than just using 0xffffffff. */
183 err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
184 rdc321x_gpio_dev->reg1_data_base,
185 &rdc321x_gpio_dev->data_reg[0]);
186 if (err)
187 return err;
188
189 err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
190 rdc321x_gpio_dev->reg2_data_base,
191 &rdc321x_gpio_dev->data_reg[1]);
192 if (err)
193 return err;
194
195 dev_info(&pdev->dev, "registering %d GPIOs\n",
196 rdc321x_gpio_dev->chip.ngpio);
197 return devm_gpiochip_add_data(&pdev->dev, &rdc321x_gpio_dev->chip,
198 rdc321x_gpio_dev);
199}
200
201static struct platform_driver rdc321x_gpio_driver = {
202 .driver.name = "rdc321x-gpio",
203 .probe = rdc321x_gpio_probe,
204};
205
206module_platform_driver(rdc321x_gpio_driver);
207
208MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
209MODULE_DESCRIPTION("RDC321x GPIO driver");
210MODULE_LICENSE("GPL");
211MODULE_ALIAS("platform:rdc321x-gpio");
212