1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * regmap based generic GPIO driver
4 *
5 * Copyright 2020 Michael Walle <michael@walle.cc>
6 */
7
8 #include <linux/bits.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/module.h>
13 #include <linux/regmap.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16
17 #include <linux/gpio/driver.h>
18 #include <linux/gpio/regmap.h>
19
20 #include "gpiolib.h"
21
22 struct gpio_regmap {
23 struct device *parent;
24 struct regmap *regmap;
25 struct gpio_chip gpio_chip;
26
27 int reg_stride;
28 int ngpio_per_reg;
29 unsigned int reg_dat_base;
30 unsigned int reg_set_base;
31 unsigned int reg_clr_base;
32 unsigned int reg_dir_in_base;
33 unsigned int reg_dir_out_base;
34 unsigned long *fixed_direction_output;
35
36 #ifdef CONFIG_REGMAP_IRQ
37 int regmap_irq_line;
38 struct regmap_irq_chip_data *irq_chip_data;
39 #endif
40
41 int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
42 unsigned int offset, unsigned int *reg,
43 unsigned int *mask);
44
45 void *driver_data;
46 };
47
gpio_regmap_addr(unsigned int addr)48 static unsigned int gpio_regmap_addr(unsigned int addr)
49 {
50 if (addr == GPIO_REGMAP_ADDR_ZERO)
51 return 0;
52
53 return addr;
54 }
55
gpio_regmap_simple_xlate(struct gpio_regmap * gpio,unsigned int base,unsigned int offset,unsigned int * reg,unsigned int * mask)56 static int gpio_regmap_simple_xlate(struct gpio_regmap *gpio,
57 unsigned int base, unsigned int offset,
58 unsigned int *reg, unsigned int *mask)
59 {
60 unsigned int line = offset % gpio->ngpio_per_reg;
61 unsigned int stride = offset / gpio->ngpio_per_reg;
62
63 *reg = base + stride * gpio->reg_stride;
64 *mask = BIT(line);
65
66 return 0;
67 }
68
gpio_regmap_get(struct gpio_chip * chip,unsigned int offset)69 static int gpio_regmap_get(struct gpio_chip *chip, unsigned int offset)
70 {
71 struct gpio_regmap *gpio = gpiochip_get_data(chip);
72 unsigned int base, val, reg, mask;
73 int ret;
74
75 /* we might not have an output register if we are input only */
76 if (gpio->reg_dat_base)
77 base = gpio_regmap_addr(gpio->reg_dat_base);
78 else
79 base = gpio_regmap_addr(gpio->reg_set_base);
80
81 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
82 if (ret)
83 return ret;
84
85 /* ensure we don't spoil any register cache with pin input values */
86 if (gpio->reg_dat_base == gpio->reg_set_base)
87 ret = regmap_read_bypassed(gpio->regmap, reg, &val);
88 else
89 ret = regmap_read(gpio->regmap, reg, &val);
90 if (ret)
91 return ret;
92
93 return !!(val & mask);
94 }
95
gpio_regmap_set(struct gpio_chip * chip,unsigned int offset,int val)96 static int gpio_regmap_set(struct gpio_chip *chip, unsigned int offset,
97 int val)
98 {
99 struct gpio_regmap *gpio = gpiochip_get_data(chip);
100 unsigned int base = gpio_regmap_addr(gpio->reg_set_base);
101 unsigned int reg, mask, mask_val;
102 int ret;
103
104 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
105 if (ret)
106 return ret;
107
108 if (val)
109 mask_val = mask;
110 else
111 mask_val = 0;
112
113 /* ignore input values which shadow the old output value */
114 if (gpio->reg_dat_base == gpio->reg_set_base)
115 ret = regmap_write_bits(gpio->regmap, reg, mask, mask_val);
116 else
117 ret = regmap_update_bits(gpio->regmap, reg, mask, mask_val);
118
119 return ret;
120 }
121
gpio_regmap_set_with_clear(struct gpio_chip * chip,unsigned int offset,int val)122 static int gpio_regmap_set_with_clear(struct gpio_chip *chip,
123 unsigned int offset, int val)
124 {
125 struct gpio_regmap *gpio = gpiochip_get_data(chip);
126 unsigned int base, reg, mask;
127 int ret;
128
129 if (val)
130 base = gpio_regmap_addr(gpio->reg_set_base);
131 else
132 base = gpio_regmap_addr(gpio->reg_clr_base);
133
134 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
135 if (ret)
136 return ret;
137
138 return regmap_write(gpio->regmap, reg, mask);
139 }
140
gpio_regmap_get_direction(struct gpio_chip * chip,unsigned int offset)141 static int gpio_regmap_get_direction(struct gpio_chip *chip,
142 unsigned int offset)
143 {
144 struct gpio_regmap *gpio = gpiochip_get_data(chip);
145 unsigned int base, val, reg, mask;
146 int invert, ret;
147
148 if (gpio->fixed_direction_output) {
149 if (test_bit(offset, gpio->fixed_direction_output))
150 return GPIO_LINE_DIRECTION_OUT;
151 else
152 return GPIO_LINE_DIRECTION_IN;
153 }
154
155 if (gpio->reg_dat_base && !gpio->reg_set_base)
156 return GPIO_LINE_DIRECTION_IN;
157 if (gpio->reg_set_base && !gpio->reg_dat_base)
158 return GPIO_LINE_DIRECTION_OUT;
159
160 if (gpio->reg_dir_out_base) {
161 base = gpio_regmap_addr(gpio->reg_dir_out_base);
162 invert = 0;
163 } else if (gpio->reg_dir_in_base) {
164 base = gpio_regmap_addr(gpio->reg_dir_in_base);
165 invert = 1;
166 } else {
167 return -ENOTSUPP;
168 }
169
170 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
171 if (ret)
172 return ret;
173
174 ret = regmap_read(gpio->regmap, reg, &val);
175 if (ret)
176 return ret;
177
178 if (!!(val & mask) ^ invert)
179 return GPIO_LINE_DIRECTION_OUT;
180 else
181 return GPIO_LINE_DIRECTION_IN;
182 }
183
gpio_regmap_set_direction(struct gpio_chip * chip,unsigned int offset,bool output)184 static int gpio_regmap_set_direction(struct gpio_chip *chip,
185 unsigned int offset, bool output)
186 {
187 struct gpio_regmap *gpio = gpiochip_get_data(chip);
188 unsigned int base, val, reg, mask;
189 int invert, ret;
190
191 if (gpio->reg_dir_out_base) {
192 base = gpio_regmap_addr(gpio->reg_dir_out_base);
193 invert = 0;
194 } else if (gpio->reg_dir_in_base) {
195 base = gpio_regmap_addr(gpio->reg_dir_in_base);
196 invert = 1;
197 } else {
198 return -ENOTSUPP;
199 }
200
201 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
202 if (ret)
203 return ret;
204
205 if (invert)
206 val = output ? 0 : mask;
207 else
208 val = output ? mask : 0;
209
210 return regmap_update_bits(gpio->regmap, reg, mask, val);
211 }
212
gpio_regmap_direction_input(struct gpio_chip * chip,unsigned int offset)213 static int gpio_regmap_direction_input(struct gpio_chip *chip,
214 unsigned int offset)
215 {
216 return gpio_regmap_set_direction(chip, offset, false);
217 }
218
gpio_regmap_direction_output(struct gpio_chip * chip,unsigned int offset,int value)219 static int gpio_regmap_direction_output(struct gpio_chip *chip,
220 unsigned int offset, int value)
221 {
222 gpio_regmap_set(chip, offset, value);
223
224 return gpio_regmap_set_direction(chip, offset, true);
225 }
226
gpio_regmap_get_drvdata(struct gpio_regmap * gpio)227 void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
228 {
229 return gpio->driver_data;
230 }
231 EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
232
233 /**
234 * gpio_regmap_register() - Register a generic regmap GPIO controller
235 * @config: configuration for gpio_regmap
236 *
237 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
238 */
gpio_regmap_register(const struct gpio_regmap_config * config)239 struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
240 {
241 struct irq_domain *irq_domain;
242 struct gpio_regmap *gpio;
243 struct gpio_chip *chip;
244 int ret;
245
246 if (!config->parent)
247 return ERR_PTR(-EINVAL);
248
249 /* we need at least one */
250 if (!config->reg_dat_base && !config->reg_set_base)
251 return ERR_PTR(-EINVAL);
252
253 /* if we have a direction register we need both input and output */
254 if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
255 (!config->reg_dat_base || !config->reg_set_base))
256 return ERR_PTR(-EINVAL);
257
258 /* we don't support having both registers simultaneously for now */
259 if (config->reg_dir_out_base && config->reg_dir_in_base)
260 return ERR_PTR(-EINVAL);
261
262 gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
263 if (!gpio)
264 return ERR_PTR(-ENOMEM);
265
266 gpio->parent = config->parent;
267 gpio->driver_data = config->drvdata;
268 gpio->regmap = config->regmap;
269 gpio->reg_dat_base = config->reg_dat_base;
270 gpio->reg_set_base = config->reg_set_base;
271 gpio->reg_clr_base = config->reg_clr_base;
272 gpio->reg_dir_in_base = config->reg_dir_in_base;
273 gpio->reg_dir_out_base = config->reg_dir_out_base;
274
275 chip = &gpio->gpio_chip;
276 chip->parent = config->parent;
277 chip->fwnode = config->fwnode;
278 chip->base = -1;
279 chip->names = config->names;
280 chip->label = config->label ?: dev_name(config->parent);
281 chip->can_sleep = regmap_might_sleep(config->regmap);
282 chip->init_valid_mask = config->init_valid_mask;
283
284 chip->request = gpiochip_generic_request;
285 chip->free = gpiochip_generic_free;
286 chip->get = gpio_regmap_get;
287 if (gpio->reg_set_base && gpio->reg_clr_base)
288 chip->set = gpio_regmap_set_with_clear;
289 else if (gpio->reg_set_base)
290 chip->set = gpio_regmap_set;
291
292 chip->get_direction = gpio_regmap_get_direction;
293 if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
294 chip->direction_input = gpio_regmap_direction_input;
295 chip->direction_output = gpio_regmap_direction_output;
296 }
297
298 chip->ngpio = config->ngpio;
299 if (!chip->ngpio) {
300 ret = gpiochip_get_ngpios(chip, chip->parent);
301 if (ret)
302 goto err_free_gpio;
303 }
304
305 if (config->fixed_direction_output) {
306 gpio->fixed_direction_output = bitmap_alloc(chip->ngpio,
307 GFP_KERNEL);
308 if (!gpio->fixed_direction_output) {
309 ret = -ENOMEM;
310 goto err_free_gpio;
311 }
312 bitmap_copy(gpio->fixed_direction_output,
313 config->fixed_direction_output, chip->ngpio);
314 }
315
316 /* if not set, assume there is only one register */
317 gpio->ngpio_per_reg = config->ngpio_per_reg;
318 if (!gpio->ngpio_per_reg)
319 gpio->ngpio_per_reg = config->ngpio;
320
321 /* if not set, assume they are consecutive */
322 gpio->reg_stride = config->reg_stride;
323 if (!gpio->reg_stride)
324 gpio->reg_stride = 1;
325
326 gpio->reg_mask_xlate = config->reg_mask_xlate;
327 if (!gpio->reg_mask_xlate)
328 gpio->reg_mask_xlate = gpio_regmap_simple_xlate;
329
330 ret = gpiochip_add_data(chip, gpio);
331 if (ret < 0)
332 goto err_free_bitmap;
333
334 #ifdef CONFIG_REGMAP_IRQ
335 if (config->regmap_irq_chip) {
336 gpio->regmap_irq_line = config->regmap_irq_line;
337 ret = regmap_add_irq_chip_fwnode(dev_fwnode(config->parent), config->regmap,
338 config->regmap_irq_line, config->regmap_irq_flags,
339 0, config->regmap_irq_chip, &gpio->irq_chip_data);
340 if (ret)
341 goto err_free_bitmap;
342
343 irq_domain = regmap_irq_get_domain(gpio->irq_chip_data);
344 } else
345 #endif
346 irq_domain = config->irq_domain;
347
348 if (irq_domain) {
349 ret = gpiochip_irqchip_add_domain(chip, irq_domain);
350 if (ret)
351 goto err_remove_gpiochip;
352 }
353
354 return gpio;
355
356 err_remove_gpiochip:
357 gpiochip_remove(chip);
358 err_free_bitmap:
359 bitmap_free(gpio->fixed_direction_output);
360 err_free_gpio:
361 kfree(gpio);
362 return ERR_PTR(ret);
363 }
364 EXPORT_SYMBOL_GPL(gpio_regmap_register);
365
366 /**
367 * gpio_regmap_unregister() - Unregister a generic regmap GPIO controller
368 * @gpio: gpio_regmap device to unregister
369 */
gpio_regmap_unregister(struct gpio_regmap * gpio)370 void gpio_regmap_unregister(struct gpio_regmap *gpio)
371 {
372 #ifdef CONFIG_REGMAP_IRQ
373 if (gpio->irq_chip_data)
374 regmap_del_irq_chip(gpio->regmap_irq_line, gpio->irq_chip_data);
375 #endif
376
377 gpiochip_remove(&gpio->gpio_chip);
378 bitmap_free(gpio->fixed_direction_output);
379 kfree(gpio);
380 }
381 EXPORT_SYMBOL_GPL(gpio_regmap_unregister);
382
devm_gpio_regmap_unregister(void * res)383 static void devm_gpio_regmap_unregister(void *res)
384 {
385 gpio_regmap_unregister(res);
386 }
387
388 /**
389 * devm_gpio_regmap_register() - resource managed gpio_regmap_register()
390 * @dev: device that is registering this GPIO device
391 * @config: configuration for gpio_regmap
392 *
393 * Managed gpio_regmap_register(). For generic regmap GPIO device registered by
394 * this function, gpio_regmap_unregister() is automatically called on driver
395 * detach. See gpio_regmap_register() for more information.
396 *
397 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
398 */
devm_gpio_regmap_register(struct device * dev,const struct gpio_regmap_config * config)399 struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
400 const struct gpio_regmap_config *config)
401 {
402 struct gpio_regmap *gpio;
403 int ret;
404
405 gpio = gpio_regmap_register(config);
406
407 if (IS_ERR(gpio))
408 return gpio;
409
410 ret = devm_add_action_or_reset(dev, devm_gpio_regmap_unregister, gpio);
411 if (ret)
412 return ERR_PTR(ret);
413
414 return gpio;
415 }
416 EXPORT_SYMBOL_GPL(devm_gpio_regmap_register);
417
418 MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
419 MODULE_DESCRIPTION("GPIO generic regmap driver core");
420 MODULE_LICENSE("GPL");
421