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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, &reg);
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