2 * GPIO Testing Device Driver
4 * Copyright (C) 2014 Kamlakant Patel <kamlakant.patel@broadcom.com>
5 * Copyright (C) 2015-2016 Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/interrupt.h>
21 #include <linux/irq.h>
22 #include <linux/irq_work.h>
23 #include <linux/debugfs.h>
24 #include <linux/uaccess.h>
28 #define GPIO_MOCKUP_NAME "gpio-mockup"
29 #define GPIO_MOCKUP_MAX_GC 10
32 GPIO_MOCKUP_DIR_OUT = 0,
33 GPIO_MOCKUP_DIR_IN = 1,
37 * struct gpio_pin_status - structure describing a GPIO status
38 * @dir: Configures direction of gpio as "in" or "out", 0=in, 1=out
39 * @value: Configures status of the gpio as 0(low) or 1(high)
41 struct gpio_mockup_line_status {
47 struct gpio_mockup_irq_context {
52 struct gpio_mockup_chip {
54 struct gpio_mockup_line_status *lines;
55 struct gpio_mockup_irq_context irq_ctx;
56 struct dentry *dbg_dir;
59 struct gpio_mockup_dbgfs_private {
60 struct gpio_mockup_chip *chip;
61 struct gpio_desc *desc;
65 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_GC << 1];
66 static int gpio_mockup_params_nr;
67 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_params_nr, 0400);
69 static bool gpio_mockup_named_lines;
70 module_param_named(gpio_mockup_named_lines,
71 gpio_mockup_named_lines, bool, 0400);
73 static const char gpio_mockup_name_start = 'A';
74 static struct dentry *gpio_mockup_dbg_dir;
76 static int gpio_mockup_get(struct gpio_chip *gc, unsigned int offset)
78 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
80 return chip->lines[offset].value;
83 static void gpio_mockup_set(struct gpio_chip *gc, unsigned int offset,
86 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
88 chip->lines[offset].value = !!value;
91 static int gpio_mockup_dirout(struct gpio_chip *gc, unsigned int offset,
94 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
96 gpio_mockup_set(gc, offset, value);
97 chip->lines[offset].dir = GPIO_MOCKUP_DIR_OUT;
102 static int gpio_mockup_dirin(struct gpio_chip *gc, unsigned int offset)
104 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
106 chip->lines[offset].dir = GPIO_MOCKUP_DIR_IN;
111 static int gpio_mockup_get_direction(struct gpio_chip *gc, unsigned int offset)
113 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
115 return chip->lines[offset].dir;
118 static int gpio_mockup_name_lines(struct device *dev,
119 struct gpio_mockup_chip *chip)
121 struct gpio_chip *gc = &chip->gc;
125 names = devm_kzalloc(dev, sizeof(char *) * gc->ngpio, GFP_KERNEL);
129 for (i = 0; i < gc->ngpio; i++) {
130 names[i] = devm_kasprintf(dev, GFP_KERNEL,
131 "%s-%d", gc->label, i);
136 gc->names = (const char *const *)names;
141 static int gpio_mockup_to_irq(struct gpio_chip *chip, unsigned int offset)
143 return chip->irq_base + offset;
146 static void gpio_mockup_irqmask(struct irq_data *data)
148 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
149 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
151 chip->lines[data->irq - gc->irq_base].irq_enabled = false;
154 static void gpio_mockup_irqunmask(struct irq_data *data)
156 struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
157 struct gpio_mockup_chip *chip = gpiochip_get_data(gc);
159 chip->lines[data->irq - gc->irq_base].irq_enabled = true;
162 static struct irq_chip gpio_mockup_irqchip = {
163 .name = GPIO_MOCKUP_NAME,
164 .irq_mask = gpio_mockup_irqmask,
165 .irq_unmask = gpio_mockup_irqunmask,
168 static void gpio_mockup_handle_irq(struct irq_work *work)
170 struct gpio_mockup_irq_context *irq_ctx;
172 irq_ctx = container_of(work, struct gpio_mockup_irq_context, work);
173 handle_simple_irq(irq_to_desc(irq_ctx->irq));
176 static int gpio_mockup_irqchip_setup(struct device *dev,
177 struct gpio_mockup_chip *chip)
179 struct gpio_chip *gc = &chip->gc;
182 irq_base = devm_irq_alloc_descs(dev, -1, 0, gc->ngpio, 0);
186 gc->irq_base = irq_base;
187 gc->irqchip = &gpio_mockup_irqchip;
189 for (i = 0; i < gc->ngpio; i++) {
190 irq_set_chip(irq_base + i, gc->irqchip);
191 irq_set_chip_data(irq_base + i, gc);
192 irq_set_handler(irq_base + i, &handle_simple_irq);
193 irq_modify_status(irq_base + i,
194 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
197 init_irq_work(&chip->irq_ctx.work, gpio_mockup_handle_irq);
202 static ssize_t gpio_mockup_event_write(struct file *file,
203 const char __user *usr_buf,
204 size_t size, loff_t *ppos)
206 struct gpio_mockup_dbgfs_private *priv;
207 struct gpio_mockup_chip *chip;
208 struct seq_file *sfile;
209 struct gpio_desc *desc;
210 struct gpio_chip *gc;
213 sfile = file->private_data;
214 priv = sfile->private;
219 rv = kstrtoint_from_user(usr_buf, size, 0, &val);
222 if (val != 0 && val != 1)
225 if (!chip->lines[priv->offset].irq_enabled)
228 gpiod_set_value_cansleep(desc, val);
229 priv->chip->irq_ctx.irq = gc->irq_base + priv->offset;
230 irq_work_queue(&priv->chip->irq_ctx.work);
235 static int gpio_mockup_event_open(struct inode *inode, struct file *file)
237 return single_open(file, NULL, inode->i_private);
240 static const struct file_operations gpio_mockup_event_ops = {
241 .owner = THIS_MODULE,
242 .open = gpio_mockup_event_open,
243 .write = gpio_mockup_event_write,
247 static void gpio_mockup_debugfs_setup(struct device *dev,
248 struct gpio_mockup_chip *chip)
250 struct gpio_mockup_dbgfs_private *priv;
251 struct dentry *evfile;
252 struct gpio_chip *gc;
258 chip->dbg_dir = debugfs_create_dir(gc->label, gpio_mockup_dbg_dir);
262 for (i = 0; i < gc->ngpio; i++) {
263 name = devm_kasprintf(dev, GFP_KERNEL, "%d", i);
267 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
273 priv->desc = &gc->gpiodev->descs[i];
275 evfile = debugfs_create_file(name, 0200, chip->dbg_dir, priv,
276 &gpio_mockup_event_ops);
284 dev_err(dev, "error creating debugfs directory\n");
287 static int gpio_mockup_add(struct device *dev,
288 struct gpio_mockup_chip *chip,
289 const char *name, int base, int ngpio)
291 struct gpio_chip *gc = &chip->gc;
297 gc->owner = THIS_MODULE;
299 gc->get = gpio_mockup_get;
300 gc->set = gpio_mockup_set;
301 gc->direction_output = gpio_mockup_dirout;
302 gc->direction_input = gpio_mockup_dirin;
303 gc->get_direction = gpio_mockup_get_direction;
304 gc->to_irq = gpio_mockup_to_irq;
306 chip->lines = devm_kzalloc(dev, sizeof(*chip->lines) * gc->ngpio,
311 if (gpio_mockup_named_lines) {
312 ret = gpio_mockup_name_lines(dev, chip);
317 ret = gpio_mockup_irqchip_setup(dev, chip);
321 ret = devm_gpiochip_add_data(dev, &chip->gc, chip);
325 if (gpio_mockup_dbg_dir)
326 gpio_mockup_debugfs_setup(dev, chip);
331 static int gpio_mockup_probe(struct platform_device *pdev)
333 struct gpio_mockup_chip *chips;
334 struct device *dev = &pdev->dev;
335 int ret, i, base, ngpio;
338 if (gpio_mockup_params_nr < 2)
341 chips = devm_kzalloc(dev,
342 sizeof(*chips) * (gpio_mockup_params_nr >> 1),
347 platform_set_drvdata(pdev, chips);
349 for (i = 0; i < gpio_mockup_params_nr >> 1; i++) {
350 base = gpio_mockup_ranges[i * 2];
353 ngpio = gpio_mockup_ranges[i * 2 + 1];
355 ngpio = gpio_mockup_ranges[i * 2 + 1] - base;
358 chip_name = devm_kasprintf(dev, GFP_KERNEL,
359 "%s-%c", GPIO_MOCKUP_NAME,
360 gpio_mockup_name_start + i);
364 ret = gpio_mockup_add(dev, &chips[i],
365 chip_name, base, ngpio);
371 dev_err(dev, "gpio<%d..%d> add failed\n",
372 base, base < 0 ? ngpio : base + ngpio);
381 static struct platform_driver gpio_mockup_driver = {
383 .name = GPIO_MOCKUP_NAME,
385 .probe = gpio_mockup_probe,
388 static struct platform_device *pdev;
389 static int __init mock_device_init(void)
393 gpio_mockup_dbg_dir = debugfs_create_dir("gpio-mockup-event", NULL);
394 if (!gpio_mockup_dbg_dir)
395 pr_err("%s: error creating debugfs directory\n",
398 pdev = platform_device_alloc(GPIO_MOCKUP_NAME, -1);
402 err = platform_device_add(pdev);
404 platform_device_put(pdev);
408 err = platform_driver_register(&gpio_mockup_driver);
410 platform_device_unregister(pdev);
417 static void __exit mock_device_exit(void)
419 debugfs_remove_recursive(gpio_mockup_dbg_dir);
420 platform_driver_unregister(&gpio_mockup_driver);
421 platform_device_unregister(pdev);
424 module_init(mock_device_init);
425 module_exit(mock_device_exit);
427 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
428 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
429 MODULE_DESCRIPTION("GPIO Testing driver");
430 MODULE_LICENSE("GPL v2");