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
18struct 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 */
30static 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
48static 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 */
67static 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
78static 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
102unlock:
103	spin_unlock(&gpch->lock);
104
105	return err;
106}
107
108/* configure GPIO pin as input */
109static 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 */
117static 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
187static struct platform_driver rdc321x_gpio_driver = {
188	.driver.name	= "rdc321x-gpio",
189	.probe		= rdc321x_gpio_probe,
190};
191
192module_platform_driver(rdc321x_gpio_driver);
193
194MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
195MODULE_DESCRIPTION("RDC321x GPIO driver");
196MODULE_LICENSE("GPL");
197MODULE_ALIAS("platform:rdc321x-gpio");
198