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gpio-rdc321x.c
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1 /*
2  * RDC321x GPIO driver
3  *
4  * Copyright (C) 2008, Volker Weiss <[email protected]>
5  * Copyright (C) 2007-2010 Florian Fainelli <[email protected]>
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 {
34  struct pci_dev *sb_pdev;
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 __devinit 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 = pdev->dev.platform_data;
139  if (!pdata) {
140  dev_err(&pdev->dev, "no platform data supplied\n");
141  return -ENODEV;
142  }
143 
144  rdc321x_gpio_dev = kzalloc(sizeof(struct rdc321x_gpio), GFP_KERNEL);
145  if (!rdc321x_gpio_dev) {
146  dev_err(&pdev->dev, "failed to allocate private data\n");
147  return -ENOMEM;
148  }
149 
150  r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg1");
151  if (!r) {
152  dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
153  err = -ENODEV;
154  goto out_free;
155  }
156 
157  spin_lock_init(&rdc321x_gpio_dev->lock);
158  rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
159  rdc321x_gpio_dev->reg1_ctrl_base = r->start;
160  rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
161 
162  r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg2");
163  if (!r) {
164  dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
165  err = -ENODEV;
166  goto out_free;
167  }
168 
169  rdc321x_gpio_dev->reg2_ctrl_base = r->start;
170  rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
171 
172  rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
173  rdc321x_gpio_dev->chip.owner = THIS_MODULE;
174  rdc321x_gpio_dev->chip.direction_input = rdc_gpio_direction_input;
175  rdc321x_gpio_dev->chip.direction_output = rdc_gpio_config;
176  rdc321x_gpio_dev->chip.get = rdc_gpio_get_value;
177  rdc321x_gpio_dev->chip.set = rdc_gpio_set_value;
178  rdc321x_gpio_dev->chip.base = 0;
179  rdc321x_gpio_dev->chip.ngpio = pdata->max_gpios;
180 
181  platform_set_drvdata(pdev, rdc321x_gpio_dev);
182 
183  /* This might not be, what others (BIOS, bootloader, etc.)
184  wrote to these registers before, but it's a good guess. Still
185  better than just using 0xffffffff. */
186  err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
187  rdc321x_gpio_dev->reg1_data_base,
188  &rdc321x_gpio_dev->data_reg[0]);
189  if (err)
190  goto out_drvdata;
191 
192  err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
193  rdc321x_gpio_dev->reg2_data_base,
194  &rdc321x_gpio_dev->data_reg[1]);
195  if (err)
196  goto out_drvdata;
197 
198  dev_info(&pdev->dev, "registering %d GPIOs\n",
199  rdc321x_gpio_dev->chip.ngpio);
200  return gpiochip_add(&rdc321x_gpio_dev->chip);
201 
202 out_drvdata:
203  platform_set_drvdata(pdev, NULL);
204 out_free:
205  kfree(rdc321x_gpio_dev);
206  return err;
207 }
208 
209 static int __devexit rdc321x_gpio_remove(struct platform_device *pdev)
210 {
211  int ret;
212  struct rdc321x_gpio *rdc321x_gpio_dev = platform_get_drvdata(pdev);
213 
214  ret = gpiochip_remove(&rdc321x_gpio_dev->chip);
215  if (ret)
216  dev_err(&pdev->dev, "failed to unregister chip\n");
217 
218  kfree(rdc321x_gpio_dev);
219  platform_set_drvdata(pdev, NULL);
220 
221  return ret;
222 }
223 
224 static struct platform_driver rdc321x_gpio_driver = {
225  .driver.name = "rdc321x-gpio",
226  .driver.owner = THIS_MODULE,
227  .probe = rdc321x_gpio_probe,
228  .remove = __devexit_p(rdc321x_gpio_remove),
229 };
230 
231 module_platform_driver(rdc321x_gpio_driver);
232 
233 MODULE_AUTHOR("Florian Fainelli <[email protected]>");
234 MODULE_DESCRIPTION("RDC321x GPIO driver");
235 MODULE_LICENSE("GPL");
236 MODULE_ALIAS("platform:rdc321x-gpio");