1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * RDC321x GPIO driver
4 *
5 * Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
6 * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
7 */
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/spinlock.h>
12 #include <linux/platform_device.h>
13 #include <linux/pci.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/mfd/rdc321x.h>
16 #include <linux/slab.h>
17
18 struct rdc321x_gpio {
19 spinlock_t lock;
20 struct pci_dev *sb_pdev;
21 u32 data_reg[2];
22 int reg1_ctrl_base;
23 int reg1_data_base;
24 int reg2_ctrl_base;
25 int reg2_data_base;
26 struct gpio_chip chip;
27 };
28
29 /* read GPIO pin */
rdc_gpio_get_value(struct gpio_chip * chip,unsigned gpio)30 static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
31 {
32 struct rdc321x_gpio *gpch;
33 u32 value = 0;
34 int reg;
35
36 gpch = gpiochip_get_data(chip);
37 reg = gpio < 32 ? gpch->reg1_data_base : gpch->reg2_data_base;
38
39 spin_lock(&gpch->lock);
40 pci_write_config_dword(gpch->sb_pdev, reg,
41 gpch->data_reg[gpio < 32 ? 0 : 1]);
42 pci_read_config_dword(gpch->sb_pdev, reg, &value);
43 spin_unlock(&gpch->lock);
44
45 return (1 << (gpio & 0x1f)) & value ? 1 : 0;
46 }
47
rdc_gpio_set_value_impl(struct gpio_chip * chip,unsigned gpio,int value)48 static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
49 unsigned gpio, int value)
50 {
51 struct rdc321x_gpio *gpch;
52 int reg = (gpio < 32) ? 0 : 1;
53
54 gpch = gpiochip_get_data(chip);
55
56 if (value)
57 gpch->data_reg[reg] |= 1 << (gpio & 0x1f);
58 else
59 gpch->data_reg[reg] &= ~(1 << (gpio & 0x1f));
60
61 pci_write_config_dword(gpch->sb_pdev,
62 reg ? gpch->reg2_data_base : gpch->reg1_data_base,
63 gpch->data_reg[reg]);
64 }
65
66 /* set GPIO pin to value */
rdc_gpio_set_value(struct gpio_chip * chip,unsigned gpio,int value)67 static void rdc_gpio_set_value(struct gpio_chip *chip,
68 unsigned gpio, int value)
69 {
70 struct rdc321x_gpio *gpch;
71
72 gpch = gpiochip_get_data(chip);
73 spin_lock(&gpch->lock);
74 rdc_gpio_set_value_impl(chip, gpio, value);
75 spin_unlock(&gpch->lock);
76 }
77
rdc_gpio_config(struct gpio_chip * chip,unsigned gpio,int value)78 static int rdc_gpio_config(struct gpio_chip *chip,
79 unsigned gpio, int value)
80 {
81 struct rdc321x_gpio *gpch;
82 int err;
83 u32 reg;
84
85 gpch = gpiochip_get_data(chip);
86
87 spin_lock(&gpch->lock);
88 err = pci_read_config_dword(gpch->sb_pdev, gpio < 32 ?
89 gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, ®);
90 if (err)
91 goto unlock;
92
93 reg |= 1 << (gpio & 0x1f);
94
95 err = pci_write_config_dword(gpch->sb_pdev, gpio < 32 ?
96 gpch->reg1_ctrl_base : gpch->reg2_ctrl_base, reg);
97 if (err)
98 goto unlock;
99
100 rdc_gpio_set_value_impl(chip, gpio, value);
101
102 unlock:
103 spin_unlock(&gpch->lock);
104
105 return err;
106 }
107
108 /* configure GPIO pin as input */
rdc_gpio_direction_input(struct gpio_chip * chip,unsigned gpio)109 static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
110 {
111 return rdc_gpio_config(chip, gpio, 1);
112 }
113
114 /*
115 * Cache the initial value of both GPIO data registers
116 */
rdc321x_gpio_probe(struct platform_device * pdev)117 static int rdc321x_gpio_probe(struct platform_device *pdev)
118 {
119 int err;
120 struct resource *r;
121 struct rdc321x_gpio *rdc321x_gpio_dev;
122 struct rdc321x_gpio_pdata *pdata;
123
124 pdata = dev_get_platdata(&pdev->dev);
125 if (!pdata) {
126 dev_err(&pdev->dev, "no platform data supplied\n");
127 return -ENODEV;
128 }
129
130 rdc321x_gpio_dev = devm_kzalloc(&pdev->dev, sizeof(struct rdc321x_gpio),
131 GFP_KERNEL);
132 if (!rdc321x_gpio_dev)
133 return -ENOMEM;
134
135 r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg1");
136 if (!r) {
137 dev_err(&pdev->dev, "failed to get gpio-reg1 resource\n");
138 return -ENODEV;
139 }
140
141 spin_lock_init(&rdc321x_gpio_dev->lock);
142 rdc321x_gpio_dev->sb_pdev = pdata->sb_pdev;
143 rdc321x_gpio_dev->reg1_ctrl_base = r->start;
144 rdc321x_gpio_dev->reg1_data_base = r->start + 0x4;
145
146 r = platform_get_resource_byname(pdev, IORESOURCE_IO, "gpio-reg2");
147 if (!r) {
148 dev_err(&pdev->dev, "failed to get gpio-reg2 resource\n");
149 return -ENODEV;
150 }
151
152 rdc321x_gpio_dev->reg2_ctrl_base = r->start;
153 rdc321x_gpio_dev->reg2_data_base = r->start + 0x4;
154
155 rdc321x_gpio_dev->chip.label = "rdc321x-gpio";
156 rdc321x_gpio_dev->chip.owner = THIS_MODULE;
157 rdc321x_gpio_dev->chip.direction_input = rdc_gpio_direction_input;
158 rdc321x_gpio_dev->chip.direction_output = rdc_gpio_config;
159 rdc321x_gpio_dev->chip.get = rdc_gpio_get_value;
160 rdc321x_gpio_dev->chip.set = rdc_gpio_set_value;
161 rdc321x_gpio_dev->chip.base = 0;
162 rdc321x_gpio_dev->chip.ngpio = pdata->max_gpios;
163
164 platform_set_drvdata(pdev, rdc321x_gpio_dev);
165
166 /* This might not be, what others (BIOS, bootloader, etc.)
167 wrote to these registers before, but it's a good guess. Still
168 better than just using 0xffffffff. */
169 err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
170 rdc321x_gpio_dev->reg1_data_base,
171 &rdc321x_gpio_dev->data_reg[0]);
172 if (err)
173 return err;
174
175 err = pci_read_config_dword(rdc321x_gpio_dev->sb_pdev,
176 rdc321x_gpio_dev->reg2_data_base,
177 &rdc321x_gpio_dev->data_reg[1]);
178 if (err)
179 return err;
180
181 dev_info(&pdev->dev, "registering %d GPIOs\n",
182 rdc321x_gpio_dev->chip.ngpio);
183 return devm_gpiochip_add_data(&pdev->dev, &rdc321x_gpio_dev->chip,
184 rdc321x_gpio_dev);
185 }
186
187 static struct platform_driver rdc321x_gpio_driver = {
188 .driver.name = "rdc321x-gpio",
189 .probe = rdc321x_gpio_probe,
190 };
191
192 module_platform_driver(rdc321x_gpio_driver);
193
194 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
195 MODULE_DESCRIPTION("RDC321x GPIO driver");
196 MODULE_LICENSE("GPL");
197 MODULE_ALIAS("platform:rdc321x-gpio");
198