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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 | /** |
25ca385d MZ |
29 | * Request a GPIO. This should be called before any of the other functions |
30 | * are used on this GPIO. | |
5f533aeb | 31 | * |
b892d127 SG |
32 | * Note: With driver model, the label is allocated so there is no need for |
33 | * the caller to preserve it. | |
34 | * | |
94740e47 NK |
35 | * @param gp GPIO number |
36 | * @param label User label for this GPIO | |
5f533aeb JH |
37 | * @return 0 if ok, -1 on error |
38 | */ | |
39 | int gpio_request(unsigned gpio, const char *label); | |
40 | ||
41 | /** | |
42 | * Stop using the GPIO. This function should not alter pin configuration. | |
43 | * | |
44 | * @param gpio GPIO number | |
45 | * @return 0 if ok, -1 on error | |
46 | */ | |
47 | int gpio_free(unsigned gpio); | |
48 | ||
9d2cb8e8 SG |
49 | /** |
50 | * Make a GPIO an input. | |
51 | * | |
5f533aeb | 52 | * @param gpio GPIO number |
9d2cb8e8 SG |
53 | * @return 0 if ok, -1 on error |
54 | */ | |
5f533aeb | 55 | int gpio_direction_input(unsigned gpio); |
9d2cb8e8 SG |
56 | |
57 | /** | |
58 | * Make a GPIO an output, and set its value. | |
59 | * | |
5f533aeb | 60 | * @param gpio GPIO number |
9d2cb8e8 SG |
61 | * @param value GPIO value (0 for low or 1 for high) |
62 | * @return 0 if ok, -1 on error | |
63 | */ | |
5f533aeb | 64 | int gpio_direction_output(unsigned gpio, int value); |
9d2cb8e8 SG |
65 | |
66 | /** | |
67 | * Get a GPIO's value. This will work whether the GPIO is an input | |
68 | * or an output. | |
69 | * | |
5f533aeb | 70 | * @param gpio GPIO number |
9d2cb8e8 SG |
71 | * @return 0 if low, 1 if high, -1 on error |
72 | */ | |
5f533aeb | 73 | int gpio_get_value(unsigned gpio); |
9d2cb8e8 SG |
74 | |
75 | /** | |
5f533aeb | 76 | * Set an output GPIO's value. The GPIO must already be an output or |
9d2cb8e8 SG |
77 | * this function may have no effect. |
78 | * | |
5f533aeb | 79 | * @param gpio GPIO number |
9d2cb8e8 SG |
80 | * @param value GPIO value (0 for low or 1 for high) |
81 | * @return 0 if ok, -1 on error | |
82 | */ | |
5f533aeb | 83 | int gpio_set_value(unsigned gpio, int value); |
96495d90 | 84 | |
89e64054 | 85 | /* State of a GPIO, as reported by get_function() */ |
96495d90 SG |
86 | enum { |
87 | GPIOF_INPUT = 0, | |
88 | GPIOF_OUTPUT, | |
89e64054 SG |
89 | GPIOF_UNUSED, /* Not claimed */ |
90 | GPIOF_UNKNOWN, /* Not known */ | |
91 | GPIOF_FUNC, /* Not used as a GPIO */ | |
92 | ||
93 | GPIOF_COUNT, | |
96495d90 SG |
94 | }; |
95 | ||
54c5d08a | 96 | struct udevice; |
96495d90 SG |
97 | |
98 | /** | |
99 | * struct struct dm_gpio_ops - Driver model GPIO operations | |
100 | * | |
101 | * Refer to functions above for description. These function largely copy | |
102 | * the old API. | |
103 | * | |
104 | * This is trying to be close to Linux GPIO API. Once the U-Boot uses the | |
105 | * new DM GPIO API, this should be really easy to flip over to the Linux | |
106 | * GPIO API-alike interface. | |
107 | * | |
25ca385d | 108 | * Also it would be useful to standardise additional functions like |
96495d90 SG |
109 | * pullup, slew rate and drive strength. |
110 | * | |
111 | * gpio_request)( and gpio_free() are optional - if NULL then they will | |
112 | * not be called. | |
113 | * | |
114 | * Note that @offset is the offset from the base GPIO of the device. So | |
115 | * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, | |
116 | * where o is the number of GPIO lines controlled by the device. A device | |
117 | * is typically used to control a single bank of GPIOs. Within complex | |
118 | * SoCs there may be many banks and therefore many devices all referring | |
119 | * to the different IO addresses within the SoC. | |
120 | * | |
25ca385d | 121 | * The uclass combines all GPIO devices together to provide a consistent |
96495d90 SG |
122 | * numbering from 0 to n-1, where n is the number of GPIOs in total across |
123 | * all devices. Be careful not to confuse offset with gpio in the parameters. | |
124 | */ | |
125 | struct dm_gpio_ops { | |
54c5d08a HS |
126 | int (*request)(struct udevice *dev, unsigned offset, const char *label); |
127 | int (*free)(struct udevice *dev, unsigned offset); | |
128 | int (*direction_input)(struct udevice *dev, unsigned offset); | |
129 | int (*direction_output)(struct udevice *dev, unsigned offset, | |
96495d90 | 130 | int value); |
54c5d08a HS |
131 | int (*get_value)(struct udevice *dev, unsigned offset); |
132 | int (*set_value)(struct udevice *dev, unsigned offset, int value); | |
89e64054 SG |
133 | /** |
134 | * get_function() Get the GPIO function | |
135 | * | |
136 | * @dev: Device to check | |
137 | * @offset: GPIO offset within that device | |
138 | * @return current function - GPIOF_... | |
139 | */ | |
54c5d08a HS |
140 | int (*get_function)(struct udevice *dev, unsigned offset); |
141 | int (*get_state)(struct udevice *dev, unsigned offset, char *state, | |
96495d90 SG |
142 | int maxlen); |
143 | }; | |
144 | ||
145 | /** | |
146 | * struct gpio_dev_priv - information about a device used by the uclass | |
147 | * | |
148 | * The uclass combines all active GPIO devices into a unified numbering | |
25ca385d | 149 | * scheme. To do this it maintains some private information about each |
96495d90 SG |
150 | * device. |
151 | * | |
152 | * To implement driver model support in your GPIO driver, add a probe | |
153 | * handler, and set @gpio_count and @bank_name correctly in that handler. | |
154 | * This tells the uclass the name of the GPIO bank and the number of GPIOs | |
155 | * it contains. | |
156 | * | |
157 | * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called | |
158 | * 'A0', 'A1', etc. | |
159 | * @gpio_count: Number of GPIOs in this device | |
160 | * @gpio_base: Base GPIO number for this device. For the first active device | |
161 | * this will be 0; the numbering for others will follow sequentially so that | |
162 | * @gpio_base for device 1 will equal the number of GPIOs in device 0. | |
b892d127 SG |
163 | * @name: Array of pointers to the name for each GPIO in this bank. The |
164 | * value of the pointer will be NULL if the GPIO has not been claimed. | |
96495d90 SG |
165 | */ |
166 | struct gpio_dev_priv { | |
167 | const char *bank_name; | |
168 | unsigned gpio_count; | |
169 | unsigned gpio_base; | |
b892d127 | 170 | char **name; |
96495d90 SG |
171 | }; |
172 | ||
173 | /* Access the GPIO operations for a device */ | |
174 | #define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) | |
175 | ||
176 | /** | |
177 | * gpio_get_bank_info - Return information about a GPIO bank/device | |
178 | * | |
179 | * This looks up a device and returns both its GPIO base name and the number | |
180 | * of GPIOs it controls. | |
181 | * | |
182 | * @dev: Device to look up | |
183 | * @offset_count: Returns number of GPIOs within this bank | |
184 | * @return bank name of this device | |
185 | */ | |
54c5d08a | 186 | const char *gpio_get_bank_info(struct udevice *dev, int *offset_count); |
96495d90 SG |
187 | |
188 | /** | |
189 | * gpio_lookup_name - Look up a GPIO name and return its details | |
190 | * | |
191 | * This is used to convert a named GPIO into a device, offset and GPIO | |
192 | * number. | |
193 | * | |
194 | * @name: GPIO name to look up | |
195 | * @devp: Returns pointer to device which contains this GPIO | |
196 | * @offsetp: Returns the offset number within this device | |
197 | * @gpiop: Returns the absolute GPIO number, numbered from 0 | |
198 | */ | |
54c5d08a | 199 | int gpio_lookup_name(const char *name, struct udevice **devp, |
96495d90 SG |
200 | unsigned int *offsetp, unsigned int *gpiop); |
201 | ||
5f533aeb | 202 | #endif /* _ASM_GENERIC_GPIO_H_ */ |