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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/gpio/driver.h>
9#include <linux/gpio/regmap.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/regmap.h>
13
14struct gpio_regmap {
15 struct device *parent;
16 struct regmap *regmap;
17 struct gpio_chip gpio_chip;
18
19 int reg_stride;
20 int ngpio_per_reg;
21 unsigned int reg_dat_base;
22 unsigned int reg_set_base;
23 unsigned int reg_clr_base;
24 unsigned int reg_dir_in_base;
25 unsigned int reg_dir_out_base;
26
27 int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
28 unsigned int offset, unsigned int *reg,
29 unsigned int *mask);
30
31 void *driver_data;
32};
33
34static unsigned int gpio_regmap_addr(unsigned int addr)
35{
36 if (addr == GPIO_REGMAP_ADDR_ZERO)
37 return 0;
38
39 return addr;
40}
41
42static int gpio_regmap_simple_xlate(struct gpio_regmap *gpio,
43 unsigned int base, unsigned int offset,
44 unsigned int *reg, unsigned int *mask)
45{
46 unsigned int line = offset % gpio->ngpio_per_reg;
47 unsigned int stride = offset / gpio->ngpio_per_reg;
48
49 *reg = base + stride * gpio->reg_stride;
50 *mask = BIT(line);
51
52 return 0;
53}
54
55static int gpio_regmap_get(struct gpio_chip *chip, unsigned int offset)
56{
57 struct gpio_regmap *gpio = gpiochip_get_data(chip);
58 unsigned int base, val, reg, mask;
59 int ret;
60
61 /* we might not have an output register if we are input only */
62 if (gpio->reg_dat_base)
63 base = gpio_regmap_addr(gpio->reg_dat_base);
64 else
65 base = gpio_regmap_addr(gpio->reg_set_base);
66
67 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
68 if (ret)
69 return ret;
70
71 ret = regmap_read(gpio->regmap, reg, &val);
72 if (ret)
73 return ret;
74
75 return !!(val & mask);
76}
77
78static void gpio_regmap_set(struct gpio_chip *chip, unsigned int offset,
79 int val)
80{
81 struct gpio_regmap *gpio = gpiochip_get_data(chip);
82 unsigned int base = gpio_regmap_addr(gpio->reg_set_base);
83 unsigned int reg, mask;
84
85 gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
86 if (val)
87 regmap_update_bits(gpio->regmap, reg, mask, mask);
88 else
89 regmap_update_bits(gpio->regmap, reg, mask, 0);
90}
91
92static void gpio_regmap_set_with_clear(struct gpio_chip *chip,
93 unsigned int offset, int val)
94{
95 struct gpio_regmap *gpio = gpiochip_get_data(chip);
96 unsigned int base, reg, mask;
97
98 if (val)
99 base = gpio_regmap_addr(gpio->reg_set_base);
100 else
101 base = gpio_regmap_addr(gpio->reg_clr_base);
102
103 gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
104 regmap_write(gpio->regmap, reg, mask);
105}
106
107static int gpio_regmap_get_direction(struct gpio_chip *chip,
108 unsigned int offset)
109{
110 struct gpio_regmap *gpio = gpiochip_get_data(chip);
111 unsigned int base, val, reg, mask;
112 int invert, ret;
113
114 if (gpio->reg_dir_out_base) {
115 base = gpio_regmap_addr(gpio->reg_dir_out_base);
116 invert = 0;
117 } else if (gpio->reg_dir_in_base) {
118 base = gpio_regmap_addr(gpio->reg_dir_in_base);
119 invert = 1;
120 } else {
121 return -EOPNOTSUPP;
122 }
123
124 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
125 if (ret)
126 return ret;
127
128 ret = regmap_read(gpio->regmap, reg, &val);
129 if (ret)
130 return ret;
131
132 if (!!(val & mask) ^ invert)
133 return GPIO_LINE_DIRECTION_OUT;
134 else
135 return GPIO_LINE_DIRECTION_IN;
136}
137
138static int gpio_regmap_set_direction(struct gpio_chip *chip,
139 unsigned int offset, bool output)
140{
141 struct gpio_regmap *gpio = gpiochip_get_data(chip);
142 unsigned int base, val, reg, mask;
143 int invert, ret;
144
145 if (gpio->reg_dir_out_base) {
146 base = gpio_regmap_addr(gpio->reg_dir_out_base);
147 invert = 0;
148 } else if (gpio->reg_dir_in_base) {
149 base = gpio_regmap_addr(gpio->reg_dir_in_base);
150 invert = 1;
151 } else {
152 return -EOPNOTSUPP;
153 }
154
155 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
156 if (ret)
157 return ret;
158
159 if (invert)
160 val = output ? 0 : mask;
161 else
162 val = output ? mask : 0;
163
164 return regmap_update_bits(gpio->regmap, reg, mask, val);
165}
166
167static int gpio_regmap_direction_input(struct gpio_chip *chip,
168 unsigned int offset)
169{
170 return gpio_regmap_set_direction(chip, offset, false);
171}
172
173static int gpio_regmap_direction_output(struct gpio_chip *chip,
174 unsigned int offset, int value)
175{
176 gpio_regmap_set(chip, offset, value);
177
178 return gpio_regmap_set_direction(chip, offset, true);
179}
180
181void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
182{
183 return gpio->driver_data;
184}
185EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
186
187/**
188 * gpio_regmap_register() - Register a generic regmap GPIO controller
189 * @config: configuration for gpio_regmap
190 *
191 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
192 */
193struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
194{
195 struct gpio_regmap *gpio;
196 struct gpio_chip *chip;
197 int ret;
198
199 if (!config->parent)
200 return ERR_PTR(-EINVAL);
201
202 if (!config->ngpio)
203 return ERR_PTR(-EINVAL);
204
205 /* we need at least one */
206 if (!config->reg_dat_base && !config->reg_set_base)
207 return ERR_PTR(-EINVAL);
208
209 /* if we have a direction register we need both input and output */
210 if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
211 (!config->reg_dat_base || !config->reg_set_base))
212 return ERR_PTR(-EINVAL);
213
214 /* we don't support having both registers simultaneously for now */
215 if (config->reg_dir_out_base && config->reg_dir_in_base)
216 return ERR_PTR(-EINVAL);
217
218 gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
219 if (!gpio)
220 return ERR_PTR(-ENOMEM);
221
222 gpio->parent = config->parent;
223 gpio->driver_data = config->drvdata;
224 gpio->regmap = config->regmap;
225 gpio->ngpio_per_reg = config->ngpio_per_reg;
226 gpio->reg_stride = config->reg_stride;
227 gpio->reg_mask_xlate = config->reg_mask_xlate;
228 gpio->reg_dat_base = config->reg_dat_base;
229 gpio->reg_set_base = config->reg_set_base;
230 gpio->reg_clr_base = config->reg_clr_base;
231 gpio->reg_dir_in_base = config->reg_dir_in_base;
232 gpio->reg_dir_out_base = config->reg_dir_out_base;
233
234 /* if not set, assume there is only one register */
235 if (!gpio->ngpio_per_reg)
236 gpio->ngpio_per_reg = config->ngpio;
237
238 /* if not set, assume they are consecutive */
239 if (!gpio->reg_stride)
240 gpio->reg_stride = 1;
241
242 if (!gpio->reg_mask_xlate)
243 gpio->reg_mask_xlate = gpio_regmap_simple_xlate;
244
245 chip = &gpio->gpio_chip;
246 chip->parent = config->parent;
247 chip->fwnode = config->fwnode;
248 chip->base = -1;
249 chip->ngpio = config->ngpio;
250 chip->names = config->names;
251 chip->label = config->label ?: dev_name(config->parent);
252
253 /*
254 * If our regmap is fast_io we should probably set can_sleep to false.
255 * Right now, the regmap doesn't save this property, nor is there any
256 * access function for it.
257 * The only regmap type which uses fast_io is regmap-mmio. For now,
258 * assume a safe default of true here.
259 */
260 chip->can_sleep = true;
261
262 chip->get = gpio_regmap_get;
263 if (gpio->reg_set_base && gpio->reg_clr_base)
264 chip->set = gpio_regmap_set_with_clear;
265 else if (gpio->reg_set_base)
266 chip->set = gpio_regmap_set;
267
268 if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
269 chip->get_direction = gpio_regmap_get_direction;
270 chip->direction_input = gpio_regmap_direction_input;
271 chip->direction_output = gpio_regmap_direction_output;
272 }
273
274 ret = gpiochip_add_data(chip, gpio);
275 if (ret < 0)
276 goto err_free_gpio;
277
278 if (config->irq_domain) {
279 ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
280 if (ret)
281 goto err_remove_gpiochip;
282 }
283
284 return gpio;
285
286err_remove_gpiochip:
287 gpiochip_remove(chip);
288err_free_gpio:
289 kfree(gpio);
290 return ERR_PTR(ret);
291}
292EXPORT_SYMBOL_GPL(gpio_regmap_register);
293
294/**
295 * gpio_regmap_unregister() - Unregister a generic regmap GPIO controller
296 * @gpio: gpio_regmap device to unregister
297 */
298void gpio_regmap_unregister(struct gpio_regmap *gpio)
299{
300 gpiochip_remove(&gpio->gpio_chip);
301 kfree(gpio);
302}
303EXPORT_SYMBOL_GPL(gpio_regmap_unregister);
304
305static void devm_gpio_regmap_unregister(void *res)
306{
307 gpio_regmap_unregister(res);
308}
309
310/**
311 * devm_gpio_regmap_register() - resource managed gpio_regmap_register()
312 * @dev: device that is registering this GPIO device
313 * @config: configuration for gpio_regmap
314 *
315 * Managed gpio_regmap_register(). For generic regmap GPIO device registered by
316 * this function, gpio_regmap_unregister() is automatically called on driver
317 * detach. See gpio_regmap_register() for more information.
318 *
319 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
320 */
321struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
322 const struct gpio_regmap_config *config)
323{
324 struct gpio_regmap *gpio;
325 int ret;
326
327 gpio = gpio_regmap_register(config);
328
329 if (IS_ERR(gpio))
330 return gpio;
331
332 ret = devm_add_action_or_reset(dev, devm_gpio_regmap_unregister, gpio);
333 if (ret)
334 return ERR_PTR(ret);
335
336 return gpio;
337}
338EXPORT_SYMBOL_GPL(devm_gpio_regmap_register);
339
340MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
341MODULE_DESCRIPTION("GPIO generic regmap driver core");
342MODULE_LICENSE("GPL");