xref: /openbmc/linux/drivers/gpio/gpio-rdc321x.c (revision d2999e1b)
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 
32 struct 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 */
44 static 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 
62 static 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 */
81 static 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 
92 static 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 
116 unlock:
117 	spin_unlock(&gpch->lock);
118 
119 	return err;
120 }
121 
122 /* configure GPIO pin as input */
123 static 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  */
131 static 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 
200 static int rdc321x_gpio_remove(struct platform_device *pdev)
201 {
202 	int ret;
203 	struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
204 
205 	ret = gpiochip_remove(&rdc321x_gpio_dev->chip);
206 	if (ret)
207 		dev_err(&pdev->dev, "failed to unregister chip\n");
208 
209 	return ret;
210 }
211 
212 static struct platform_driver rdc321x_gpio_driver = {
213 	.driver.name	= "rdc321x-gpio",
214 	.driver.owner	= THIS_MODULE,
215 	.probe		= rdc321x_gpio_probe,
216 	.remove		= rdc321x_gpio_remove,
217 };
218 
219 module_platform_driver(rdc321x_gpio_driver);
220 
221 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
222 MODULE_DESCRIPTION("RDC321x GPIO driver");
223 MODULE_LICENSE("GPL");
224 MODULE_ALIAS("platform:rdc321x-gpio");
225