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9d2cb8e8 SG |
1 | /* |
2 | * Copyright (c) 2011 The Chromium OS Authors. | |
5f533aeb | 3 | * Copyright (c) 2011, NVIDIA Corp. All rights reserved. |
1a459660 | 4 | * SPDX-License-Identifier: GPL-2.0+ |
9d2cb8e8 SG |
5 | */ |
6 | ||
5f533aeb JH |
7 | #ifndef _ASM_GENERIC_GPIO_H_ |
8 | #define _ASM_GENERIC_GPIO_H_ | |
9 | ||
9d2cb8e8 SG |
10 | /* |
11 | * Generic GPIO API for U-Boot | |
12 | * | |
13 | * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined | |
14 | * by the SOC/architecture. | |
15 | * | |
16 | * Each GPIO can be an input or output. If an input then its value can | |
17 | * be read as 0 or 1. If an output then its value can be set to 0 or 1. | |
18 | * If you try to write an input then the value is undefined. If you try | |
19 | * to read an output, barring something very unusual, you will get | |
20 | * back the value of the output that you previously set. | |
21 | * | |
22 | * In some cases the operation may fail, for example if the GPIO number | |
23 | * is out of range, or the GPIO is not available because its pin is | |
24 | * being used by another function. In that case, functions may return | |
25 | * an error value of -1. | |
26 | */ | |
27 | ||
5f533aeb | 28 | /** |
94740e47 NK |
29 | * Request a gpio. This should be called before any of the other functions |
30 | * are used on this gpio. | |
5f533aeb | 31 | * |
94740e47 NK |
32 | * @param gp GPIO number |
33 | * @param label User label for this GPIO | |
5f533aeb JH |
34 | * @return 0 if ok, -1 on error |
35 | */ | |
36 | int gpio_request(unsigned gpio, const char *label); | |
37 | ||
38 | /** | |
39 | * Stop using the GPIO. This function should not alter pin configuration. | |
40 | * | |
41 | * @param gpio GPIO number | |
42 | * @return 0 if ok, -1 on error | |
43 | */ | |
44 | int gpio_free(unsigned gpio); | |
45 | ||
9d2cb8e8 SG |
46 | /** |
47 | * Make a GPIO an input. | |
48 | * | |
5f533aeb | 49 | * @param gpio GPIO number |
9d2cb8e8 SG |
50 | * @return 0 if ok, -1 on error |
51 | */ | |
5f533aeb | 52 | int gpio_direction_input(unsigned gpio); |
9d2cb8e8 SG |
53 | |
54 | /** | |
55 | * Make a GPIO an output, and set its value. | |
56 | * | |
5f533aeb | 57 | * @param gpio GPIO number |
9d2cb8e8 SG |
58 | * @param value GPIO value (0 for low or 1 for high) |
59 | * @return 0 if ok, -1 on error | |
60 | */ | |
5f533aeb | 61 | int gpio_direction_output(unsigned gpio, int value); |
9d2cb8e8 SG |
62 | |
63 | /** | |
64 | * Get a GPIO's value. This will work whether the GPIO is an input | |
65 | * or an output. | |
66 | * | |
5f533aeb | 67 | * @param gpio GPIO number |
9d2cb8e8 SG |
68 | * @return 0 if low, 1 if high, -1 on error |
69 | */ | |
5f533aeb | 70 | int gpio_get_value(unsigned gpio); |
9d2cb8e8 SG |
71 | |
72 | /** | |
5f533aeb | 73 | * Set an output GPIO's value. The GPIO must already be an output or |
9d2cb8e8 SG |
74 | * this function may have no effect. |
75 | * | |
5f533aeb | 76 | * @param gpio GPIO number |
9d2cb8e8 SG |
77 | * @param value GPIO value (0 for low or 1 for high) |
78 | * @return 0 if ok, -1 on error | |
79 | */ | |
5f533aeb | 80 | int gpio_set_value(unsigned gpio, int value); |
96495d90 SG |
81 | |
82 | /* State of a GPIO, as reported by get_state() */ | |
83 | enum { | |
84 | GPIOF_INPUT = 0, | |
85 | GPIOF_OUTPUT, | |
86 | GPIOF_UNKNOWN, | |
87 | }; | |
88 | ||
54c5d08a | 89 | struct udevice; |
96495d90 SG |
90 | |
91 | /** | |
92 | * struct struct dm_gpio_ops - Driver model GPIO operations | |
93 | * | |
94 | * Refer to functions above for description. These function largely copy | |
95 | * the old API. | |
96 | * | |
97 | * This is trying to be close to Linux GPIO API. Once the U-Boot uses the | |
98 | * new DM GPIO API, this should be really easy to flip over to the Linux | |
99 | * GPIO API-alike interface. | |
100 | * | |
101 | * Akso it would be useful to standardise additional functions like | |
102 | * pullup, slew rate and drive strength. | |
103 | * | |
104 | * gpio_request)( and gpio_free() are optional - if NULL then they will | |
105 | * not be called. | |
106 | * | |
107 | * Note that @offset is the offset from the base GPIO of the device. So | |
108 | * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, | |
109 | * where o is the number of GPIO lines controlled by the device. A device | |
110 | * is typically used to control a single bank of GPIOs. Within complex | |
111 | * SoCs there may be many banks and therefore many devices all referring | |
112 | * to the different IO addresses within the SoC. | |
113 | * | |
114 | * The uclass combines all GPIO devices togther to provide a consistent | |
115 | * numbering from 0 to n-1, where n is the number of GPIOs in total across | |
116 | * all devices. Be careful not to confuse offset with gpio in the parameters. | |
117 | */ | |
118 | struct dm_gpio_ops { | |
54c5d08a HS |
119 | int (*request)(struct udevice *dev, unsigned offset, const char *label); |
120 | int (*free)(struct udevice *dev, unsigned offset); | |
121 | int (*direction_input)(struct udevice *dev, unsigned offset); | |
122 | int (*direction_output)(struct udevice *dev, unsigned offset, | |
96495d90 | 123 | int value); |
54c5d08a HS |
124 | int (*get_value)(struct udevice *dev, unsigned offset); |
125 | int (*set_value)(struct udevice *dev, unsigned offset, int value); | |
126 | int (*get_function)(struct udevice *dev, unsigned offset); | |
127 | int (*get_state)(struct udevice *dev, unsigned offset, char *state, | |
96495d90 SG |
128 | int maxlen); |
129 | }; | |
130 | ||
131 | /** | |
132 | * struct gpio_dev_priv - information about a device used by the uclass | |
133 | * | |
134 | * The uclass combines all active GPIO devices into a unified numbering | |
135 | * scheme. To do this it maintains some private information aobut each | |
136 | * device. | |
137 | * | |
138 | * To implement driver model support in your GPIO driver, add a probe | |
139 | * handler, and set @gpio_count and @bank_name correctly in that handler. | |
140 | * This tells the uclass the name of the GPIO bank and the number of GPIOs | |
141 | * it contains. | |
142 | * | |
143 | * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called | |
144 | * 'A0', 'A1', etc. | |
145 | * @gpio_count: Number of GPIOs in this device | |
146 | * @gpio_base: Base GPIO number for this device. For the first active device | |
147 | * this will be 0; the numbering for others will follow sequentially so that | |
148 | * @gpio_base for device 1 will equal the number of GPIOs in device 0. | |
149 | */ | |
150 | struct gpio_dev_priv { | |
151 | const char *bank_name; | |
152 | unsigned gpio_count; | |
153 | unsigned gpio_base; | |
154 | }; | |
155 | ||
156 | /* Access the GPIO operations for a device */ | |
157 | #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) | |
158 | ||
159 | /** | |
160 | * gpio_get_bank_info - Return information about a GPIO bank/device | |
161 | * | |
162 | * This looks up a device and returns both its GPIO base name and the number | |
163 | * of GPIOs it controls. | |
164 | * | |
165 | * @dev: Device to look up | |
166 | * @offset_count: Returns number of GPIOs within this bank | |
167 | * @return bank name of this device | |
168 | */ | |
54c5d08a | 169 | const char *gpio_get_bank_info(struct udevice *dev, int *offset_count); |
96495d90 SG |
170 | |
171 | /** | |
172 | * gpio_lookup_name - Look up a GPIO name and return its details | |
173 | * | |
174 | * This is used to convert a named GPIO into a device, offset and GPIO | |
175 | * number. | |
176 | * | |
177 | * @name: GPIO name to look up | |
178 | * @devp: Returns pointer to device which contains this GPIO | |
179 | * @offsetp: Returns the offset number within this device | |
180 | * @gpiop: Returns the absolute GPIO number, numbered from 0 | |
181 | */ | |
54c5d08a | 182 | int gpio_lookup_name(const char *name, struct udevice **devp, |
96495d90 SG |
183 | unsigned int *offsetp, unsigned int *gpiop); |
184 | ||
5f533aeb | 185 | #endif /* _ASM_GENERIC_GPIO_H_ */ |