1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * LPC32xxGPIO driver
4 *
5 * (C) Copyright 2014 DENX Software Engineering GmbH
6 * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
7 */
8
9 #include <common.h>
10 #include <asm/io.h>
11 #include <asm/arch-lpc32xx/cpu.h>
12 #include <asm/arch-lpc32xx/gpio.h>
13 #include <asm-generic/gpio.h>
14 #include <dm.h>
15
16 /**
17 * LPC32xx GPIOs work in banks but are non-homogeneous:
18 * - each bank holds a different number of GPIOs
19 * - some GPIOs are input/ouput, some input only, some output only;
20 * - some GPIOs have different meanings as an input and as an output;
21 * - some GPIOs are controlled on a given port and bit index, but
22 * read on another one.
23 *
24 * In order to keep this code simple, GPIOS are considered here as
25 * homogeneous and linear, from 0 to 159.
26 *
27 * ** WARNING #1 **
28 *
29 * Client code is responsible for properly using valid GPIO numbers,
30 * including cases where a single physical GPIO has differing numbers
31 * for setting its direction, reading it and/or writing to it.
32 *
33 * ** WARNING #2 **
34 *
35 * Please read NOTE in description of lpc32xx_gpio_get_function().
36 */
37
38 #define LPC32XX_GPIOS 160
39
40 struct lpc32xx_gpio_priv {
41 struct gpio_regs *regs;
42 /* GPIO FUNCTION: SEE WARNING #2 */
43 signed char function[LPC32XX_GPIOS];
44 };
45
46 /**
47 * We have 4 GPIO ports of 32 bits each
48 *
49 * Port mapping offset (32 bits each):
50 * - Port 0: 0
51 * - Port 1: 32
52 * - Port 2: 64
53 * - Port 3: GPO / GPIO (output): 96
54 * - Port 3: GPI: 128
55 */
56
57 #define MAX_GPIO 160
58
59 #define GPIO_TO_PORT(gpio) ((gpio / 32) & 7)
60 #define GPIO_TO_RANK(gpio) (gpio % 32)
61 #define GPIO_TO_MASK(gpio) (1 << (gpio % 32))
62
63 /**
64 * Configure a GPIO number 'offset' as input
65 */
66
lpc32xx_gpio_direction_input(struct udevice * dev,unsigned offset)67 static int lpc32xx_gpio_direction_input(struct udevice *dev, unsigned offset)
68 {
69 int port, mask;
70 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
71 struct gpio_regs *regs = gpio_priv->regs;
72
73 port = GPIO_TO_PORT(offset);
74 mask = GPIO_TO_MASK(offset);
75
76 switch (port) {
77 case 0:
78 writel(mask, ®s->p0_dir_clr);
79 break;
80 case 1:
81 writel(mask, ®s->p1_dir_clr);
82 break;
83 case 2:
84 /* ports 2 and 3 share a common direction */
85 writel(mask, ®s->p2_p3_dir_clr);
86 break;
87 case 3:
88 /* Setup direction only for GPIO_xx. */
89 if ((mask >= 25) && (mask <= 30))
90 writel(mask, ®s->p2_p3_dir_clr);
91 break;
92 case 4:
93 /* GPI_xx; nothing to do. */
94 break;
95 default:
96 return -1;
97 }
98
99 /* GPIO FUNCTION: SEE WARNING #2 */
100 gpio_priv->function[offset] = GPIOF_INPUT;
101
102 return 0;
103 }
104
105 /**
106 * Get the value of a GPIO
107 */
108
lpc32xx_gpio_get_value(struct udevice * dev,unsigned offset)109 static int lpc32xx_gpio_get_value(struct udevice *dev, unsigned offset)
110 {
111 int port, rank, mask, value;
112 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
113 struct gpio_regs *regs = gpio_priv->regs;
114
115 port = GPIO_TO_PORT(offset);
116
117 switch (port) {
118 case 0:
119 value = readl(®s->p0_inp_state);
120 break;
121 case 1:
122 value = readl(®s->p1_inp_state);
123 break;
124 case 2:
125 value = readl(®s->p2_inp_state);
126 break;
127 case 3:
128 /* Read GPO_xx and GPIO_xx (as output) using p3_outp_state. */
129 value = readl(®s->p3_outp_state);
130 break;
131 case 4:
132 /* Read GPI_xx and GPIO_xx (as input) using p3_inp_state. */
133 value = readl(®s->p3_inp_state);
134 break;
135 default:
136 return -1;
137 }
138
139 rank = GPIO_TO_RANK(offset);
140 mask = GPIO_TO_MASK(offset);
141
142 return (value & mask) >> rank;
143 }
144
145 /**
146 * Set a GPIO
147 */
148
gpio_set(struct udevice * dev,unsigned gpio)149 static int gpio_set(struct udevice *dev, unsigned gpio)
150 {
151 int port, mask;
152 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
153 struct gpio_regs *regs = gpio_priv->regs;
154
155 port = GPIO_TO_PORT(gpio);
156 mask = GPIO_TO_MASK(gpio);
157
158 switch (port) {
159 case 0:
160 writel(mask, ®s->p0_outp_set);
161 break;
162 case 1:
163 writel(mask, ®s->p1_outp_set);
164 break;
165 case 2:
166 writel(mask, ®s->p2_outp_set);
167 break;
168 case 3:
169 writel(mask, ®s->p3_outp_set);
170 break;
171 case 4:
172 /* GPI_xx; invalid. */
173 default:
174 return -1;
175 }
176 return 0;
177 }
178
179 /**
180 * Clear a GPIO
181 */
182
gpio_clr(struct udevice * dev,unsigned gpio)183 static int gpio_clr(struct udevice *dev, unsigned gpio)
184 {
185 int port, mask;
186 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
187 struct gpio_regs *regs = gpio_priv->regs;
188
189 port = GPIO_TO_PORT(gpio);
190 mask = GPIO_TO_MASK(gpio);
191
192 switch (port) {
193 case 0:
194 writel(mask, ®s->p0_outp_clr);
195 break;
196 case 1:
197 writel(mask, ®s->p1_outp_clr);
198 break;
199 case 2:
200 writel(mask, ®s->p2_outp_clr);
201 break;
202 case 3:
203 writel(mask, ®s->p3_outp_clr);
204 break;
205 case 4:
206 /* GPI_xx; invalid. */
207 default:
208 return -1;
209 }
210 return 0;
211 }
212
213 /**
214 * Set the value of a GPIO
215 */
216
lpc32xx_gpio_set_value(struct udevice * dev,unsigned offset,int value)217 static int lpc32xx_gpio_set_value(struct udevice *dev, unsigned offset,
218 int value)
219 {
220 if (value)
221 return gpio_set(dev, offset);
222 else
223 return gpio_clr(dev, offset);
224 }
225
226 /**
227 * Configure a GPIO number 'offset' as output with given initial value.
228 */
229
lpc32xx_gpio_direction_output(struct udevice * dev,unsigned offset,int value)230 static int lpc32xx_gpio_direction_output(struct udevice *dev, unsigned offset,
231 int value)
232 {
233 int port, mask;
234 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
235 struct gpio_regs *regs = gpio_priv->regs;
236
237 port = GPIO_TO_PORT(offset);
238 mask = GPIO_TO_MASK(offset);
239
240 switch (port) {
241 case 0:
242 writel(mask, ®s->p0_dir_set);
243 break;
244 case 1:
245 writel(mask, ®s->p1_dir_set);
246 break;
247 case 2:
248 /* ports 2 and 3 share a common direction */
249 writel(mask, ®s->p2_p3_dir_set);
250 break;
251 case 3:
252 /* Setup direction only for GPIO_xx. */
253 if ((mask >= 25) && (mask <= 30))
254 writel(mask, ®s->p2_p3_dir_set);
255 break;
256 case 4:
257 /* GPI_xx; invalid. */
258 default:
259 return -1;
260 }
261
262 /* GPIO FUNCTION: SEE WARNING #2 */
263 gpio_priv->function[offset] = GPIOF_OUTPUT;
264
265 return lpc32xx_gpio_set_value(dev, offset, value);
266 }
267
268 /**
269 * GPIO functions are supposed to be computed from their current
270 * configuration, but that's way too complicated in LPC32XX. A simpler
271 * approach is used, where the GPIO functions are cached in an array.
272 * When the GPIO is in use, its function is either "input" or "output"
273 * depending on its direction, otherwise its function is "unknown".
274 *
275 * ** NOTE **
276 *
277 * THIS APPROACH WAS CHOSEN DU TO THE COMPLEX NATURE OF THE LPC32XX
278 * GPIOS; DO NOT TAKE THIS AS AN EXAMPLE FOR NEW CODE.
279 */
280
lpc32xx_gpio_get_function(struct udevice * dev,unsigned offset)281 static int lpc32xx_gpio_get_function(struct udevice *dev, unsigned offset)
282 {
283 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
284 return gpio_priv->function[offset];
285 }
286
287 static const struct dm_gpio_ops gpio_lpc32xx_ops = {
288 .direction_input = lpc32xx_gpio_direction_input,
289 .direction_output = lpc32xx_gpio_direction_output,
290 .get_value = lpc32xx_gpio_get_value,
291 .set_value = lpc32xx_gpio_set_value,
292 .get_function = lpc32xx_gpio_get_function,
293 };
294
lpc32xx_gpio_probe(struct udevice * dev)295 static int lpc32xx_gpio_probe(struct udevice *dev)
296 {
297 struct lpc32xx_gpio_priv *gpio_priv = dev_get_priv(dev);
298 struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
299
300 if (dev_of_offset(dev) == -1) {
301 /* Tell the uclass how many GPIOs we have */
302 uc_priv->gpio_count = LPC32XX_GPIOS;
303 }
304
305 /* set base address for GPIO registers */
306 gpio_priv->regs = (struct gpio_regs *)GPIO_BASE;
307
308 /* all GPIO functions are unknown until requested */
309 /* GPIO FUNCTION: SEE WARNING #2 */
310 memset(gpio_priv->function, GPIOF_UNKNOWN, sizeof(gpio_priv->function));
311
312 return 0;
313 }
314
315 U_BOOT_DRIVER(gpio_lpc32xx) = {
316 .name = "gpio_lpc32xx",
317 .id = UCLASS_GPIO,
318 .ops = &gpio_lpc32xx_ops,
319 .probe = lpc32xx_gpio_probe,
320 .priv_auto = sizeof(struct lpc32xx_gpio_priv),
321 };
322