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(fw: gpio->fw, tag: RPI_FIRMWARE_GET_GPIO_CONFIG, |
65 | data: &get, len: 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(fw: gpio->fw, tag: RPI_FIRMWARE_SET_GPIO_CONFIG, |
94 | data: &set_in, len: 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(fw: gpio->fw, tag: RPI_FIRMWARE_SET_GPIO_CONFIG, |
123 | data: &set_out, len: 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(fw: gpio->fw, tag: RPI_FIRMWARE_GET_GPIO_CONFIG, |
143 | data: &get, len: 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 | } |
150 | if (get.direction) |
151 | return GPIO_LINE_DIRECTION_OUT; |
152 | |
153 | return GPIO_LINE_DIRECTION_IN; |
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(fw: gpio->fw, tag: RPI_FIRMWARE_GET_GPIO_STATE, |
168 | data: &get, len: 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(fw: gpio->fw, tag: RPI_FIRMWARE_SET_GPIO_STATE, |
190 | data: &set, len: 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(node: np); |
206 | if (!fw_node) { |
207 | dev_err(dev, "Missing firmware node\n" ); |
208 | return -ENOENT; |
209 | } |
210 | |
211 | fw = devm_rpi_firmware_get(dev: &pdev->dev, firmware_node: fw_node); |
212 | of_node_put(node: fw_node); |
213 | if (!fw) |
214 | return -EPROBE_DEFER; |
215 | |
216 | rpi_gpio = devm_kzalloc(dev, size: 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.base = -1; |
225 | rpi_gpio->gc.ngpio = NUM_GPIO; |
226 | |
227 | rpi_gpio->gc.direction_input = rpi_exp_gpio_dir_in; |
228 | rpi_gpio->gc.direction_output = rpi_exp_gpio_dir_out; |
229 | rpi_gpio->gc.get_direction = rpi_exp_gpio_get_direction; |
230 | rpi_gpio->gc.get = rpi_exp_gpio_get; |
231 | rpi_gpio->gc.set = rpi_exp_gpio_set; |
232 | rpi_gpio->gc.can_sleep = true; |
233 | |
234 | return devm_gpiochip_add_data(dev, &rpi_gpio->gc, rpi_gpio); |
235 | } |
236 | |
237 | static const struct of_device_id rpi_exp_gpio_ids[] = { |
238 | { .compatible = "raspberrypi,firmware-gpio" }, |
239 | { } |
240 | }; |
241 | MODULE_DEVICE_TABLE(of, rpi_exp_gpio_ids); |
242 | |
243 | static struct platform_driver rpi_exp_gpio_driver = { |
244 | .driver = { |
245 | .name = MODULE_NAME, |
246 | .of_match_table = rpi_exp_gpio_ids, |
247 | }, |
248 | .probe = rpi_exp_gpio_probe, |
249 | }; |
250 | module_platform_driver(rpi_exp_gpio_driver); |
251 | |
252 | MODULE_LICENSE("GPL" ); |
253 | MODULE_AUTHOR("Dave Stevenson <dave.stevenson@raspberrypi.org>" ); |
254 | MODULE_DESCRIPTION("Raspberry Pi 3 expander GPIO driver" ); |
255 | MODULE_ALIAS("platform:rpi-exp-gpio" ); |
256 | |