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, &reg, &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, &reg, &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, &reg, &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, &reg, &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, &reg, &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_set_drvdata(struct gpio_regmap *gpio, void *data)
182{
183	gpio->driver_data = data;
184}
185EXPORT_SYMBOL_GPL(gpio_regmap_set_drvdata);
186
187void *gpio_regmap_get_drvdata(struct gpio_regmap *gpio)
188{
189	return gpio->driver_data;
190}
191EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
192
193/**
194 * gpio_regmap_register() - Register a generic regmap GPIO controller
195 * @config: configuration for gpio_regmap
196 *
197 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
198 */
199struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
200{
201	struct gpio_regmap *gpio;
202	struct gpio_chip *chip;
203	int ret;
204
205	if (!config->parent)
206		return ERR_PTR(-EINVAL);
207
208	if (!config->ngpio)
209		return ERR_PTR(-EINVAL);
210
211	/* we need at least one */
212	if (!config->reg_dat_base && !config->reg_set_base)
213		return ERR_PTR(-EINVAL);
214
215	/* if we have a direction register we need both input and output */
216	if ((config->reg_dir_out_base || config->reg_dir_in_base) &&
217	    (!config->reg_dat_base || !config->reg_set_base))
218		return ERR_PTR(-EINVAL);
219
220	/* we don't support having both registers simultaneously for now */
221	if (config->reg_dir_out_base && config->reg_dir_in_base)
222		return ERR_PTR(-EINVAL);
223
224	gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
225	if (!gpio)
226		return ERR_PTR(-ENOMEM);
227
228	gpio->parent = config->parent;
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->base = -1;
253	chip->ngpio = config->ngpio;
254	chip->names = config->names;
255	chip->label = config->label ?: dev_name(config->parent);
256
257	/*
258	 * If our regmap is fast_io we should probably set can_sleep to false.
259	 * Right now, the regmap doesn't save this property, nor is there any
260	 * access function for it.
261	 * The only regmap type which uses fast_io is regmap-mmio. For now,
262	 * assume a safe default of true here.
263	 */
264	chip->can_sleep = true;
265
266	chip->get = gpio_regmap_get;
267	if (gpio->reg_set_base && gpio->reg_clr_base)
268		chip->set = gpio_regmap_set_with_clear;
269	else if (gpio->reg_set_base)
270		chip->set = gpio_regmap_set;
271
272	if (gpio->reg_dir_in_base || gpio->reg_dir_out_base) {
273		chip->get_direction = gpio_regmap_get_direction;
274		chip->direction_input = gpio_regmap_direction_input;
275		chip->direction_output = gpio_regmap_direction_output;
276	}
277
278	ret = gpiochip_add_data(chip, gpio);
279	if (ret < 0)
280		goto err_free_gpio;
281
282	if (config->irq_domain) {
283		ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
284		if (ret)
285			goto err_remove_gpiochip;
286	}
287
288	return gpio;
289
290err_remove_gpiochip:
291	gpiochip_remove(chip);
292err_free_gpio:
293	kfree(gpio);
294	return ERR_PTR(ret);
295}
296EXPORT_SYMBOL_GPL(gpio_regmap_register);
297
298/**
299 * gpio_regmap_unregister() - Unregister a generic regmap GPIO controller
300 * @gpio: gpio_regmap device to unregister
301 */
302void gpio_regmap_unregister(struct gpio_regmap *gpio)
303{
304	gpiochip_remove(&gpio->gpio_chip);
305	kfree(gpio);
306}
307EXPORT_SYMBOL_GPL(gpio_regmap_unregister);
308
309static void devm_gpio_regmap_unregister(struct device *dev, void *res)
310{
311	gpio_regmap_unregister(*(struct gpio_regmap **)res);
312}
313
314/**
315 * devm_gpio_regmap_register() - resource managed gpio_regmap_register()
316 * @dev: device that is registering this GPIO device
317 * @config: configuration for gpio_regmap
318 *
319 * Managed gpio_regmap_register(). For generic regmap GPIO device registered by
320 * this function, gpio_regmap_unregister() is automatically called on driver
321 * detach. See gpio_regmap_register() for more information.
322 *
323 * Return: A pointer to the registered gpio_regmap or ERR_PTR error value.
324 */
325struct gpio_regmap *devm_gpio_regmap_register(struct device *dev,
326					      const struct gpio_regmap_config *config)
327{
328	struct gpio_regmap **ptr, *gpio;
329
330	ptr = devres_alloc(devm_gpio_regmap_unregister, sizeof(*ptr),
331			   GFP_KERNEL);
332	if (!ptr)
333		return ERR_PTR(-ENOMEM);
334
335	gpio = gpio_regmap_register(config);
336	if (!IS_ERR(gpio)) {
337		*ptr = gpio;
338		devres_add(dev, ptr);
339	} else {
340		devres_free(ptr);
341	}
342
343	return gpio;
344}
345EXPORT_SYMBOL_GPL(devm_gpio_regmap_register);
346
347MODULE_AUTHOR("Michael Walle <michael@walle.cc>");
348MODULE_DESCRIPTION("GPIO generic regmap driver core");
349MODULE_LICENSE("GPL");