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.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 = container_of(chip, struct rdc321x_gpio, 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 = container_of(chip, struct rdc321x_gpio, 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 = container_of(chip, struct rdc321x_gpio, 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 = container_of(chip, struct rdc321x_gpio, 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 gpiochip_add(&rdc321x_gpio_dev->chip);
198}
199
200static int rdc321x_gpio_remove(struct platform_device *pdev)
201{
202	struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
203
204	gpiochip_remove(&rdc321x_gpio_dev->chip);
205
206	return 0;
207}
208
209static struct platform_driver rdc321x_gpio_driver = {
210	.driver.name	= "rdc321x-gpio",
211	.driver.owner	= THIS_MODULE,
212	.probe		= rdc321x_gpio_probe,
213	.remove		= rdc321x_gpio_remove,
214};
215
216module_platform_driver(rdc321x_gpio_driver);
217
218MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
219MODULE_DESCRIPTION("RDC321x GPIO driver");
220MODULE_LICENSE("GPL");
221MODULE_ALIAS("platform:rdc321x-gpio");
222