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
14 struct 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
gpio_regmap_addr(unsigned int addr)34 static 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
gpio_regmap_simple_xlate(struct gpio_regmap * gpio,unsigned int base,unsigned int offset,unsigned int * reg,unsigned int * mask)42 static 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
gpio_regmap_get(struct gpio_chip * chip,unsigned int offset)55 static 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
gpio_regmap_set(struct gpio_chip * chip,unsigned int offset,int val)78 static 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
gpio_regmap_set_with_clear(struct gpio_chip * chip,unsigned int offset,int val)92 static 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
gpio_regmap_get_direction(struct gpio_chip * chip,unsigned int offset)107 static 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_dat_base && !gpio->reg_set_base)
115 return GPIO_LINE_DIRECTION_IN;
116 if (gpio->reg_set_base && !gpio->reg_dat_base)
117 return GPIO_LINE_DIRECTION_OUT;
118
119 if (gpio->reg_dir_out_base) {
120 base = gpio_regmap_addr(gpio->reg_dir_out_base);
121 invert = 0;
122 } else if (gpio->reg_dir_in_base) {
123 base = gpio_regmap_addr(gpio->reg_dir_in_base);
124 invert = 1;
125 } else {
126 return -EOPNOTSUPP;
127 }
128
129 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
130 if (ret)
131 return ret;
132
133 ret = regmap_read(gpio->regmap, reg, &val);
134 if (ret)
135 return ret;
136
137 if (!!(val & mask) ^ invert)
138 return GPIO_LINE_DIRECTION_OUT;
139 else
140 return GPIO_LINE_DIRECTION_IN;
141 }
142
gpio_regmap_set_direction(struct gpio_chip * chip,unsigned int offset,bool output)143 static int gpio_regmap_set_direction(struct gpio_chip *chip,
144 unsigned int offset, bool output)
145 {
146 struct gpio_regmap *gpio = gpiochip_get_data(chip);
147 unsigned int base, val, reg, mask;
148 int invert, ret;
149
150 if (gpio->reg_dir_out_base) {
151 base = gpio_regmap_addr(gpio->reg_dir_out_base);
152 invert = 0;
153 } else if (gpio->reg_dir_in_base) {
154 base = gpio_regmap_addr(gpio->reg_dir_in_base);
155 invert = 1;
156 } else {
157 return -EOPNOTSUPP;
158 }
159
160 ret = gpio->reg_mask_xlate(gpio, base, offset, ®, &mask);
161 if (ret)
162 return ret;
163
164 if (invert)
165 val = output ? 0 : mask;
166 else
167 val = output ? mask : 0;
168
169 return regmap_update_bits(gpio->regmap, reg, mask, val);
170 }
171
gpio_regmap_direction_input(struct gpio_chip * chip,unsigned int offset)172 static int gpio_regmap_direction_input(struct gpio_chip *chip,
173 unsigned int offset)
174 {
175 return gpio_regmap_set_direction(chip, offset, false);
176 }
177
gpio_regmap_direction_output(struct gpio_chip * chip,unsigned int offset,int value)178 static int gpio_regmap_direction_output(struct gpio_chip *chip,
179 unsigned int offset, int value)
180 {
181 gpio_regmap_set(chip, offset, value);
182
183 return gpio_regmap_set_direction(chip, offset, true);
184 }
185
gpio_regmap_get_drvdata(struct gpio_regmap * gpio)186 void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
187 {
188 return gpio->driver_data;
189 }
190 EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
191
192 /**
193 * gpio_regmap_register() - Register a generic regmap GPIO controller
194 * @config: configuration for gpio_regmap
195 *
196 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
197 */
gpio_regmap_register(const struct gpio_regmap_config * config)198 struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
199 {
200 struct gpio_regmap *gpio;
201 struct gpio_chip *chip;
202 int ret;
203
204 if (!config->parent)
205 return ERR_PTR(-EINVAL);
206
207 if (!config->ngpio)
208 return ERR_PTR(-EINVAL);
209
210 /* we need at least one */
211 if (!config->reg_dat_base && !config->reg_set_base)
212 return ERR_PTR(-EINVAL);
213
214 /* if we have a direction register we need both input and output */
215 if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
216 (!config->reg_dat_base || !config->reg_set_base))
217 return ERR_PTR(-EINVAL);
218
219 /* we don't support having both registers simultaneously for now */
220 if (config->reg_dir_out_base && config->reg_dir_in_base)
221 return ERR_PTR(-EINVAL);
222
223 gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
224 if (!gpio)
225 return ERR_PTR(-ENOMEM);
226
227 gpio->parent = config->parent;
228 gpio->driver_data = config->drvdata;
229 gpio->regmap = config->regmap;
230 gpio->ngpio_per_reg = config->ngpio_per_reg;
231 gpio->reg_stride = config->reg_stride;
232 gpio->reg_mask_xlate = config->reg_mask_xlate;
233 gpio->reg_dat_base = config->reg_dat_base;
234 gpio->reg_set_base = config->reg_set_base;
235 gpio->reg_clr_base = config->reg_clr_base;
236 gpio->reg_dir_in_base = config->reg_dir_in_base;
237 gpio->reg_dir_out_base = config->reg_dir_out_base;
238
239 /* if not set, assume there is only one register */
240 if (!gpio->ngpio_per_reg)
241 gpio->ngpio_per_reg = config->ngpio;
242
243 /* if not set, assume they are consecutive */
244 if (!gpio->reg_stride)
245 gpio->reg_stride = 1;
246
247 if (!gpio->reg_mask_xlate)
248 gpio->reg_mask_xlate = gpio_regmap_simple_xlate;
249
250 chip = &gpio->gpio_chip;
251 chip->parent = config->parent;
252 chip->fwnode = config->fwnode;
253 chip->base = -1;
254 chip->ngpio = config->ngpio;
255 chip->names = config->names;
256 chip->label = config->label ?: dev_name(config->parent);
257 chip->can_sleep = regmap_might_sleep(config->regmap);
258
259 chip->get = gpio_regmap_get;
260 if (gpio->reg_set_base && gpio->reg_clr_base)
261 chip->set = gpio_regmap_set_with_clear;
262 else if (gpio->reg_set_base)
263 chip->set = gpio_regmap_set;
264
265 chip->get_direction = gpio_regmap_get_direction;
266 if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
267 chip->direction_input = gpio_regmap_direction_input;
268 chip->direction_output = gpio_regmap_direction_output;
269 }
270
271 ret = gpiochip_add_data(chip, gpio);
272 if (ret < 0)
273 goto err_free_gpio;
274
275 if (config->irq_domain) {
276 ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
277 if (ret)
278 goto err_remove_gpiochip;
279 }
280
281 return gpio;
282
283 err_remove_gpiochip:
284 gpiochip_remove(chip);
285 err_free_gpio:
286 kfree(gpio);
287 return ERR_PTR(ret);
288 }
289 EXPORT_SYMBOL_GPL(gpio_regmap_register);
290
291 /**
292 * gpio_regmap_unregister() - Unregister a generic regmap GPIO controller
293 * @gpio: gpio_regmap device to unregister
294 */
gpio_regmap_unregister(struct gpio_regmap * gpio)295 void gpio_regmap_unregister(struct gpio_regmap *gpio)
296 {
297 gpiochip_remove(&gpio->gpio_chip);
298 kfree(gpio);
299 }
300 EXPORT_SYMBOL_GPL(gpio_regmap_unregister);
301
devm_gpio_regmap_unregister(void * res)302 static void devm_gpio_regmap_unregister(void *res)
303 {
304 gpio_regmap_unregister(res);
305 }
306
307 /**
308 * devm_gpio_regmap_register() - resource managed gpio_regmap_register()
309 * @dev: device that is registering this GPIO device
310 * @config: configuration for gpio_regmap
311 *
312 * Managed gpio_regmap_register(). For generic regmap GPIO device registered by
313 * this function, gpio_regmap_unregister() is automatically called on driver
314 * detach. See gpio_regmap_register() for more information.
315 *
316 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
317 */
devm_gpio_regmap_register(struct device * dev,const struct gpio_regmap_config * config)318 struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
319 const struct gpio_regmap_config *config)
320 {
321 struct gpio_regmap *gpio;
322 int ret;
323
324 gpio = gpio_regmap_register(config);
325
326 if (IS_ERR(gpio))
327 return gpio;
328
329 ret = devm_add_action_or_reset(dev, devm_gpio_regmap_unregister, gpio);
330 if (ret)
331 return ERR_PTR(ret);
332
333 return gpio;
334 }
335 EXPORT_SYMBOL_GPL(devm_gpio_regmap_register);
336
337 MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
338 MODULE_DESCRIPTION("GPIO generic regmap driver core");
339 MODULE_LICENSE("GPL");
340