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1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Raspberry Pi 3 expander GPIO driver | |
4 | * | |
5 | * Uses the firmware mailbox service to communicate with the | |
6 | * GPIO expander on the VPU. | |
7 | * | |
8 | * Copyright (C) 2017 Raspberry Pi Trading Ltd. | |
9 | */ | |
10 | ||
11 | #include <linux/err.h> | |
12 | #include <linux/gpio/driver.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <soc/bcm2835/raspberrypi-firmware.h> | |
16 | ||
17 | #define MODULE_NAME "raspberrypi-exp-gpio" | |
18 | #define NUM_GPIO 8 | |
19 | ||
20 | #define RPI_EXP_GPIO_BASE 128 | |
21 | ||
22 | #define RPI_EXP_GPIO_DIR_IN 0 | |
23 | #define RPI_EXP_GPIO_DIR_OUT 1 | |
24 | ||
25 | struct rpi_exp_gpio { | |
26 | struct gpio_chip gc; | |
27 | struct rpi_firmware *fw; | |
28 | }; | |
29 | ||
30 | /* VC4 firmware mailbox interface data structures */ | |
31 | ||
32 | struct gpio_set_config { | |
33 | u32 gpio; | |
34 | u32 direction; | |
35 | u32 polarity; | |
36 | u32 term_en; | |
37 | u32 term_pull_up; | |
38 | u32 state; | |
39 | }; | |
40 | ||
41 | struct gpio_get_config { | |
42 | u32 gpio; | |
43 | u32 direction; | |
44 | u32 polarity; | |
45 | u32 term_en; | |
46 | u32 term_pull_up; | |
47 | }; | |
48 | ||
49 | struct gpio_get_set_state { | |
50 | u32 gpio; | |
51 | u32 state; | |
52 | }; | |
53 | ||
54 | static int rpi_exp_gpio_get_polarity(struct gpio_chip *gc, unsigned int off) | |
55 | { | |
56 | struct rpi_exp_gpio *gpio; | |
57 | struct gpio_get_config get; | |
58 | int ret; | |
59 | ||
60 | gpio = gpiochip_get_data(gc); | |
61 | ||
62 | get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
63 | ||
64 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, | |
65 | &get, sizeof(get)); | |
66 | if (ret || get.gpio != 0) { | |
67 | dev_err(gc->parent, "Failed to get GPIO %u config (%d %x)\n", | |
68 | off, ret, get.gpio); | |
69 | return ret ? ret : -EIO; | |
70 | } | |
71 | return get.polarity; | |
72 | } | |
73 | ||
74 | static int rpi_exp_gpio_dir_in(struct gpio_chip *gc, unsigned int off) | |
75 | { | |
76 | struct rpi_exp_gpio *gpio; | |
77 | struct gpio_set_config set_in; | |
78 | int ret; | |
79 | ||
80 | gpio = gpiochip_get_data(gc); | |
81 | ||
82 | set_in.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
83 | set_in.direction = RPI_EXP_GPIO_DIR_IN; | |
84 | set_in.term_en = 0; /* termination disabled */ | |
85 | set_in.term_pull_up = 0; /* n/a as termination disabled */ | |
86 | set_in.state = 0; /* n/a as configured as an input */ | |
87 | ||
88 | ret = rpi_exp_gpio_get_polarity(gc, off); | |
89 | if (ret < 0) | |
90 | return ret; | |
91 | set_in.polarity = ret; /* Retain existing setting */ | |
92 | ||
93 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, | |
94 | &set_in, sizeof(set_in)); | |
95 | if (ret || set_in.gpio != 0) { | |
96 | dev_err(gc->parent, "Failed to set GPIO %u to input (%d %x)\n", | |
97 | off, ret, set_in.gpio); | |
98 | return ret ? ret : -EIO; | |
99 | } | |
100 | return 0; | |
101 | } | |
102 | ||
103 | static int rpi_exp_gpio_dir_out(struct gpio_chip *gc, unsigned int off, int val) | |
104 | { | |
105 | struct rpi_exp_gpio *gpio; | |
106 | struct gpio_set_config set_out; | |
107 | int ret; | |
108 | ||
109 | gpio = gpiochip_get_data(gc); | |
110 | ||
111 | set_out.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
112 | set_out.direction = RPI_EXP_GPIO_DIR_OUT; | |
113 | set_out.term_en = 0; /* n/a as an output */ | |
114 | set_out.term_pull_up = 0; /* n/a as termination disabled */ | |
115 | set_out.state = val; /* Output state */ | |
116 | ||
117 | ret = rpi_exp_gpio_get_polarity(gc, off); | |
118 | if (ret < 0) | |
119 | return ret; | |
120 | set_out.polarity = ret; /* Retain existing setting */ | |
121 | ||
122 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_CONFIG, | |
123 | &set_out, sizeof(set_out)); | |
124 | if (ret || set_out.gpio != 0) { | |
125 | dev_err(gc->parent, "Failed to set GPIO %u to output (%d %x)\n", | |
126 | off, ret, set_out.gpio); | |
127 | return ret ? ret : -EIO; | |
128 | } | |
129 | return 0; | |
130 | } | |
131 | ||
132 | static int rpi_exp_gpio_get_direction(struct gpio_chip *gc, unsigned int off) | |
133 | { | |
134 | struct rpi_exp_gpio *gpio; | |
135 | struct gpio_get_config get; | |
136 | int ret; | |
137 | ||
138 | gpio = gpiochip_get_data(gc); | |
139 | ||
140 | get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
141 | ||
142 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_CONFIG, | |
143 | &get, sizeof(get)); | |
144 | if (ret || get.gpio != 0) { | |
145 | dev_err(gc->parent, | |
146 | "Failed to get GPIO %u config (%d %x)\n", off, ret, | |
147 | get.gpio); | |
148 | return ret ? ret : -EIO; | |
149 | } | |
e42615ec MV |
150 | if (get.direction) |
151 | return GPIO_LINE_DIRECTION_OUT; | |
152 | ||
153 | return GPIO_LINE_DIRECTION_IN; | |
a98d90e7 DS |
154 | } |
155 | ||
156 | static int rpi_exp_gpio_get(struct gpio_chip *gc, unsigned int off) | |
157 | { | |
158 | struct rpi_exp_gpio *gpio; | |
159 | struct gpio_get_set_state get; | |
160 | int ret; | |
161 | ||
162 | gpio = gpiochip_get_data(gc); | |
163 | ||
164 | get.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
165 | get.state = 0; /* storage for returned value */ | |
166 | ||
167 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_GET_GPIO_STATE, | |
168 | &get, sizeof(get)); | |
169 | if (ret || get.gpio != 0) { | |
170 | dev_err(gc->parent, | |
171 | "Failed to get GPIO %u state (%d %x)\n", off, ret, | |
172 | get.gpio); | |
173 | return ret ? ret : -EIO; | |
174 | } | |
175 | return !!get.state; | |
176 | } | |
177 | ||
178 | static void rpi_exp_gpio_set(struct gpio_chip *gc, unsigned int off, int val) | |
179 | { | |
180 | struct rpi_exp_gpio *gpio; | |
181 | struct gpio_get_set_state set; | |
182 | int ret; | |
183 | ||
184 | gpio = gpiochip_get_data(gc); | |
185 | ||
186 | set.gpio = off + RPI_EXP_GPIO_BASE; /* GPIO to update */ | |
187 | set.state = val; /* Output state */ | |
188 | ||
189 | ret = rpi_firmware_property(gpio->fw, RPI_FIRMWARE_SET_GPIO_STATE, | |
190 | &set, sizeof(set)); | |
191 | if (ret || set.gpio != 0) | |
192 | dev_err(gc->parent, | |
193 | "Failed to set GPIO %u state (%d %x)\n", off, ret, | |
194 | set.gpio); | |
195 | } | |
196 | ||
197 | static int rpi_exp_gpio_probe(struct platform_device *pdev) | |
198 | { | |
199 | struct device *dev = &pdev->dev; | |
200 | struct device_node *np = dev->of_node; | |
201 | struct device_node *fw_node; | |
202 | struct rpi_firmware *fw; | |
203 | struct rpi_exp_gpio *rpi_gpio; | |
204 | ||
205 | fw_node = of_get_parent(np); | |
206 | if (!fw_node) { | |
207 | dev_err(dev, "Missing firmware node\n"); | |
208 | return -ENOENT; | |
209 | } | |
210 | ||
211 | fw = rpi_firmware_get(fw_node); | |
85af74c4 | 212 | of_node_put(fw_node); |
a98d90e7 DS |
213 | if (!fw) |
214 | return -EPROBE_DEFER; | |
215 | ||
216 | rpi_gpio = devm_kzalloc(dev, sizeof(*rpi_gpio), GFP_KERNEL); | |
217 | if (!rpi_gpio) | |
218 | return -ENOMEM; | |
219 | ||
220 | rpi_gpio->fw = fw; | |
221 | rpi_gpio->gc.parent = dev; | |
222 | rpi_gpio->gc.label = MODULE_NAME; | |
223 | rpi_gpio->gc.owner = THIS_MODULE; | |
224 | rpi_gpio->gc.of_node = np; | |
225 | rpi_gpio->gc.base = -1; | |
226 | rpi_gpio->gc.ngpio = NUM_GPIO; | |
227 | ||
228 | rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in; | |
229 | rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out; | |
230 | rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction; | |
231 | rpi_gpio->gc.get = rpi_exp_gpio_get; | |
232 | rpi_gpio->gc.set = rpi_exp_gpio_set; | |
233 | rpi_gpio->gc.can_sleep = true; | |
234 | ||
235 | return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio); | |
236 | } | |
237 | ||
238 | static const struct of_device_id rpi_exp_gpio_ids[] = { | |
239 | { .compatible = "raspberrypi,firmware-gpio" }, | |
240 | { } | |
241 | }; | |
242 | MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids); | |
243 | ||
244 | static struct platform_driver rpi_exp_gpio_driver = { | |
245 | .driver = { | |
246 | .name = MODULE_NAME, | |
247 | .of_match_table = of_match_ptr(rpi_exp_gpio_ids), | |
248 | }, | |
249 | .probe = rpi_exp_gpio_probe, | |
250 | }; | |
251 | module_platform_driver(rpi_exp_gpio_driver); | |
252 | ||
253 | MODULE_LICENSE("GPL"); | |
254 | MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>"); | |
255 | MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver"); | |
256 | MODULE_ALIAS("platform:rpi-exp-gpio"); |