xref: /openbmc/linux/drivers/gpio/gpio-vx855.c (revision 872982ce)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
4  *
5  * Copyright (C) 2009 VIA Technologies, Inc.
6  * Copyright (C) 2010 One Laptop per Child
7  * Author: Harald Welte <HaraldWelte@viatech.com>
8  * All rights reserved.
9  */
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/gpio/driver.h>
13 #include <linux/slab.h>
14 #include <linux/device.h>
15 #include <linux/platform_device.h>
16 #include <linux/pci.h>
17 #include <linux/io.h>
18 
19 #define MODULE_NAME "vx855_gpio"
20 
21 /* The VX855 south bridge has the following GPIO pins:
22  *	GPI 0...13	General Purpose Input
23  *	GPO 0...12	General Purpose Output
24  *	GPIO 0...14	General Purpose I/O (Open-Drain)
25  */
26 
27 #define NR_VX855_GPI	14
28 #define NR_VX855_GPO	13
29 #define NR_VX855_GPIO	15
30 
31 #define NR_VX855_GPInO	(NR_VX855_GPI + NR_VX855_GPO)
32 #define NR_VX855_GP	(NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
33 
34 struct vx855_gpio {
35 	struct gpio_chip gpio;
36 	spinlock_t lock;
37 	u32 io_gpi;
38 	u32 io_gpo;
39 };
40 
41 /* resolve a GPIx into the corresponding bit position */
gpi_i_bit(int i)42 static inline u_int32_t gpi_i_bit(int i)
43 {
44 	if (i < 10)
45 		return 1 << i;
46 	else
47 		return 1 << (i + 14);
48 }
49 
gpo_o_bit(int i)50 static inline u_int32_t gpo_o_bit(int i)
51 {
52 	if (i < 11)
53 		return 1 << i;
54 	else
55 		return 1 << (i + 14);
56 }
57 
gpio_i_bit(int i)58 static inline u_int32_t gpio_i_bit(int i)
59 {
60 	if (i < 14)
61 		return 1 << (i + 10);
62 	else
63 		return 1 << (i + 14);
64 }
65 
gpio_o_bit(int i)66 static inline u_int32_t gpio_o_bit(int i)
67 {
68 	if (i < 14)
69 		return 1 << (i + 11);
70 	else
71 		return 1 << (i + 13);
72 }
73 
74 /* Mapping between numeric GPIO ID and the actual GPIO hardware numbering:
75  * 0..13	GPI 0..13
76  * 14..26	GPO 0..12
77  * 27..41	GPIO 0..14
78  */
79 
vx855gpio_direction_input(struct gpio_chip * gpio,unsigned int nr)80 static int vx855gpio_direction_input(struct gpio_chip *gpio,
81 				     unsigned int nr)
82 {
83 	struct vx855_gpio *vg = gpiochip_get_data(gpio);
84 	unsigned long flags;
85 	u_int32_t reg_out;
86 
87 	/* Real GPI bits are always in input direction */
88 	if (nr < NR_VX855_GPI)
89 		return 0;
90 
91 	/* Real GPO bits cannot be put in output direction */
92 	if (nr < NR_VX855_GPInO)
93 		return -EINVAL;
94 
95 	/* Open Drain GPIO have to be set to one */
96 	spin_lock_irqsave(&vg->lock, flags);
97 	reg_out = inl(vg->io_gpo);
98 	reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
99 	outl(reg_out, vg->io_gpo);
100 	spin_unlock_irqrestore(&vg->lock, flags);
101 
102 	return 0;
103 }
104 
vx855gpio_get(struct gpio_chip * gpio,unsigned int nr)105 static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
106 {
107 	struct vx855_gpio *vg = gpiochip_get_data(gpio);
108 	u_int32_t reg_in;
109 	int ret = 0;
110 
111 	if (nr < NR_VX855_GPI) {
112 		reg_in = inl(vg->io_gpi);
113 		if (reg_in & gpi_i_bit(nr))
114 			ret = 1;
115 	} else if (nr < NR_VX855_GPInO) {
116 		/* GPO don't have an input bit, we need to read it
117 		 * back from the output register */
118 		reg_in = inl(vg->io_gpo);
119 		if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
120 			ret = 1;
121 	} else {
122 		reg_in = inl(vg->io_gpi);
123 		if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
124 			ret = 1;
125 	}
126 
127 	return ret;
128 }
129 
vx855gpio_set(struct gpio_chip * gpio,unsigned int nr,int val)130 static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
131 			  int val)
132 {
133 	struct vx855_gpio *vg = gpiochip_get_data(gpio);
134 	unsigned long flags;
135 	u_int32_t reg_out;
136 
137 	/* True GPI cannot be switched to output mode */
138 	if (nr < NR_VX855_GPI)
139 		return;
140 
141 	spin_lock_irqsave(&vg->lock, flags);
142 	reg_out = inl(vg->io_gpo);
143 	if (nr < NR_VX855_GPInO) {
144 		if (val)
145 			reg_out |= gpo_o_bit(nr - NR_VX855_GPI);
146 		else
147 			reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
148 	} else {
149 		if (val)
150 			reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
151 		else
152 			reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
153 	}
154 	outl(reg_out, vg->io_gpo);
155 	spin_unlock_irqrestore(&vg->lock, flags);
156 }
157 
vx855gpio_direction_output(struct gpio_chip * gpio,unsigned int nr,int val)158 static int vx855gpio_direction_output(struct gpio_chip *gpio,
159 				      unsigned int nr, int val)
160 {
161 	/* True GPI cannot be switched to output mode */
162 	if (nr < NR_VX855_GPI)
163 		return -EINVAL;
164 
165 	/* True GPO don't need to be switched to output mode,
166 	 * and GPIO are open-drain, i.e. also need no switching,
167 	 * so all we do is set the level */
168 	vx855gpio_set(gpio, nr, val);
169 
170 	return 0;
171 }
172 
vx855gpio_set_config(struct gpio_chip * gpio,unsigned int nr,unsigned long config)173 static int vx855gpio_set_config(struct gpio_chip *gpio, unsigned int nr,
174 				unsigned long config)
175 {
176 	enum pin_config_param param = pinconf_to_config_param(config);
177 
178 	/* The GPI cannot be single-ended */
179 	if (nr < NR_VX855_GPI)
180 		return -EINVAL;
181 
182 	/* The GPO's are push-pull */
183 	if (nr < NR_VX855_GPInO) {
184 		if (param != PIN_CONFIG_DRIVE_PUSH_PULL)
185 			return -ENOTSUPP;
186 		return 0;
187 	}
188 
189 	/* The GPIO's are open drain */
190 	if (param != PIN_CONFIG_DRIVE_OPEN_DRAIN)
191 		return -ENOTSUPP;
192 
193 	return 0;
194 }
195 
196 static const char *vx855gpio_names[NR_VX855_GP] = {
197 	"VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
198 	"VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
199 	"VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
200 	"VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
201 	"VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
202 	"VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
203 	"VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
204 	"VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
205 	"VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
206 	"VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
207 };
208 
vx855gpio_gpio_setup(struct vx855_gpio * vg)209 static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
210 {
211 	struct gpio_chip *c = &vg->gpio;
212 
213 	c->label = "VX855 South Bridge";
214 	c->owner = THIS_MODULE;
215 	c->direction_input = vx855gpio_direction_input;
216 	c->direction_output = vx855gpio_direction_output;
217 	c->get = vx855gpio_get;
218 	c->set = vx855gpio_set;
219 	c->set_config = vx855gpio_set_config;
220 	c->dbg_show = NULL;
221 	c->base = 0;
222 	c->ngpio = NR_VX855_GP;
223 	c->can_sleep = false;
224 	c->names = vx855gpio_names;
225 }
226 
227 /* This platform device is ordinarily registered by the vx855 mfd driver */
vx855gpio_probe(struct platform_device * pdev)228 static int vx855gpio_probe(struct platform_device *pdev)
229 {
230 	struct resource *res_gpi;
231 	struct resource *res_gpo;
232 	struct vx855_gpio *vg;
233 
234 	res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
235 	res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
236 	if (!res_gpi || !res_gpo)
237 		return -EBUSY;
238 
239 	vg = devm_kzalloc(&pdev->dev, sizeof(*vg), GFP_KERNEL);
240 	if (!vg)
241 		return -ENOMEM;
242 
243 	dev_info(&pdev->dev, "found VX855 GPIO controller\n");
244 	vg->io_gpi = res_gpi->start;
245 	vg->io_gpo = res_gpo->start;
246 	spin_lock_init(&vg->lock);
247 
248 	/*
249 	 * A single byte is used to control various GPIO ports on the VX855,
250 	 * and in the case of the OLPC XO-1.5, some of those ports are used
251 	 * for switches that are interpreted and exposed through ACPI. ACPI
252 	 * will have reserved the region, so our own reservation will not
253 	 * succeed. Ignore and continue.
254 	 */
255 
256 	if (!devm_request_region(&pdev->dev, res_gpi->start,
257 				 resource_size(res_gpi), MODULE_NAME "_gpi"))
258 		dev_warn(&pdev->dev,
259 			"GPI I/O resource busy, probably claimed by ACPI\n");
260 
261 	if (!devm_request_region(&pdev->dev, res_gpo->start,
262 				 resource_size(res_gpo), MODULE_NAME "_gpo"))
263 		dev_warn(&pdev->dev,
264 			"GPO I/O resource busy, probably claimed by ACPI\n");
265 
266 	vx855gpio_gpio_setup(vg);
267 
268 	return devm_gpiochip_add_data(&pdev->dev, &vg->gpio, vg);
269 }
270 
271 static struct platform_driver vx855gpio_driver = {
272 	.driver = {
273 		.name	= MODULE_NAME,
274 	},
275 	.probe		= vx855gpio_probe,
276 };
277 
278 module_platform_driver(vx855gpio_driver);
279 
280 MODULE_LICENSE("GPL");
281 MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
282 MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
283 MODULE_ALIAS("platform:vx855_gpio");
284