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
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
{
46 struct gpio_mockup_irq_context
{
51 struct gpio_mockup_chip
{
53 struct gpio_mockup_line_status
*lines
;
54 struct gpio_mockup_irq_context irq_ctx
;
55 struct dentry
*dbg_dir
;
58 struct gpio_mockup_dbgfs_private
{
59 struct gpio_mockup_chip
*chip
;
60 struct gpio_desc
*desc
;
64 static int gpio_mockup_ranges
[GPIO_MOCKUP_MAX_GC
<< 1];
65 static int gpio_mockup_params_nr
;
66 module_param_array(gpio_mockup_ranges
, int, &gpio_mockup_params_nr
, 0400);
68 static bool gpio_mockup_named_lines
;
69 module_param_named(gpio_mockup_named_lines
,
70 gpio_mockup_named_lines
, bool, 0400);
72 static const char gpio_mockup_name_start
= 'A';
73 static struct dentry
*gpio_mockup_dbg_dir
;
75 static int gpio_mockup_get(struct gpio_chip
*gc
, unsigned int offset
)
77 struct gpio_mockup_chip
*chip
= gpiochip_get_data(gc
);
79 return chip
->lines
[offset
].value
;
82 static void gpio_mockup_set(struct gpio_chip
*gc
, unsigned int offset
,
85 struct gpio_mockup_chip
*chip
= gpiochip_get_data(gc
);
87 chip
->lines
[offset
].value
= !!value
;
90 static int gpio_mockup_dirout(struct gpio_chip
*gc
, unsigned int offset
,
93 struct gpio_mockup_chip
*chip
= gpiochip_get_data(gc
);
95 gpio_mockup_set(gc
, offset
, value
);
96 chip
->lines
[offset
].dir
= DIR_OUT
;
101 static int gpio_mockup_dirin(struct gpio_chip
*gc
, unsigned int offset
)
103 struct gpio_mockup_chip
*chip
= gpiochip_get_data(gc
);
105 chip
->lines
[offset
].dir
= DIR_IN
;
110 static int gpio_mockup_get_direction(struct gpio_chip
*gc
, unsigned int offset
)
112 struct gpio_mockup_chip
*chip
= gpiochip_get_data(gc
);
114 return chip
->lines
[offset
].dir
;
117 static int gpio_mockup_name_lines(struct device
*dev
,
118 struct gpio_mockup_chip
*chip
)
120 struct gpio_chip
*gc
= &chip
->gc
;
124 names
= devm_kzalloc(dev
, sizeof(char *) * gc
->ngpio
, GFP_KERNEL
);
128 for (i
= 0; i
< gc
->ngpio
; i
++) {
129 names
[i
] = devm_kasprintf(dev
, GFP_KERNEL
,
130 "%s-%d", gc
->label
, i
);
135 gc
->names
= (const char *const *)names
;
140 static int gpio_mockup_to_irq(struct gpio_chip
*chip
, unsigned int offset
)
142 return chip
->irq_base
+ offset
;
146 * While we should generally support irqmask and irqunmask, this driver is
147 * for testing purposes only so we don't care.
149 static void gpio_mockup_irqmask(struct irq_data
*d
) { }
150 static void gpio_mockup_irqunmask(struct irq_data
*d
) { }
152 static struct irq_chip gpio_mockup_irqchip
= {
153 .name
= GPIO_MOCKUP_NAME
,
154 .irq_mask
= gpio_mockup_irqmask
,
155 .irq_unmask
= gpio_mockup_irqunmask
,
158 static void gpio_mockup_handle_irq(struct irq_work
*work
)
160 struct gpio_mockup_irq_context
*irq_ctx
;
162 irq_ctx
= container_of(work
, struct gpio_mockup_irq_context
, work
);
163 handle_simple_irq(irq_to_desc(irq_ctx
->irq
));
166 static int gpio_mockup_irqchip_setup(struct device
*dev
,
167 struct gpio_mockup_chip
*chip
)
169 struct gpio_chip
*gc
= &chip
->gc
;
172 irq_base
= irq_alloc_descs(-1, 0, gc
->ngpio
, 0);
176 gc
->irq_base
= irq_base
;
177 gc
->irqchip
= &gpio_mockup_irqchip
;
179 for (i
= 0; i
< gc
->ngpio
; i
++) {
180 irq_set_chip(irq_base
+ i
, gc
->irqchip
);
181 irq_set_handler(irq_base
+ i
, &handle_simple_irq
);
182 irq_modify_status(irq_base
+ i
,
183 IRQ_NOREQUEST
| IRQ_NOAUTOEN
, IRQ_NOPROBE
);
186 init_irq_work(&chip
->irq_ctx
.work
, gpio_mockup_handle_irq
);
191 static ssize_t
gpio_mockup_event_write(struct file
*file
,
192 const char __user
*usr_buf
,
193 size_t size
, loff_t
*ppos
)
195 struct gpio_mockup_dbgfs_private
*priv
;
196 struct gpio_mockup_chip
*chip
;
197 struct seq_file
*sfile
;
198 struct gpio_desc
*desc
;
199 struct gpio_chip
*gc
;
203 sfile
= file
->private_data
;
204 priv
= sfile
->private;
209 if (copy_from_user(&buf
, usr_buf
, 1))
219 gpiod_set_value_cansleep(desc
, val
);
220 priv
->chip
->irq_ctx
.irq
= gc
->irq_base
+ priv
->offset
;
221 irq_work_queue(&priv
->chip
->irq_ctx
.work
);
226 static int gpio_mockup_event_open(struct inode
*inode
, struct file
*file
)
228 return single_open(file
, NULL
, inode
->i_private
);
231 static const struct file_operations gpio_mockup_event_ops
= {
232 .owner
= THIS_MODULE
,
233 .open
= gpio_mockup_event_open
,
234 .write
= gpio_mockup_event_write
,
238 static void gpio_mockup_debugfs_setup(struct device
*dev
,
239 struct gpio_mockup_chip
*chip
)
241 struct gpio_mockup_dbgfs_private
*priv
;
242 struct dentry
*evfile
;
243 struct gpio_chip
*gc
;
249 chip
->dbg_dir
= debugfs_create_dir(gc
->label
, gpio_mockup_dbg_dir
);
253 for (i
= 0; i
< gc
->ngpio
; i
++) {
254 name
= devm_kasprintf(dev
, GFP_KERNEL
, "%d", i
);
258 priv
= devm_kzalloc(dev
, sizeof(*priv
), GFP_KERNEL
);
264 priv
->desc
= &gc
->gpiodev
->descs
[i
];
266 evfile
= debugfs_create_file(name
, 0200, chip
->dbg_dir
, priv
,
267 &gpio_mockup_event_ops
);
275 dev_err(dev
, "error creating debugfs directory\n");
278 static int gpio_mockup_add(struct device
*dev
,
279 struct gpio_mockup_chip
*chip
,
280 const char *name
, int base
, int ngpio
)
282 struct gpio_chip
*gc
= &chip
->gc
;
288 gc
->owner
= THIS_MODULE
;
290 gc
->get
= gpio_mockup_get
;
291 gc
->set
= gpio_mockup_set
;
292 gc
->direction_output
= gpio_mockup_dirout
;
293 gc
->direction_input
= gpio_mockup_dirin
;
294 gc
->get_direction
= gpio_mockup_get_direction
;
295 gc
->to_irq
= gpio_mockup_to_irq
;
297 chip
->lines
= devm_kzalloc(dev
, sizeof(*chip
->lines
) * gc
->ngpio
,
302 if (gpio_mockup_named_lines
) {
303 ret
= gpio_mockup_name_lines(dev
, chip
);
308 ret
= gpio_mockup_irqchip_setup(dev
, chip
);
312 ret
= devm_gpiochip_add_data(dev
, &chip
->gc
, chip
);
316 if (gpio_mockup_dbg_dir
)
317 gpio_mockup_debugfs_setup(dev
, chip
);
322 static int gpio_mockup_probe(struct platform_device
*pdev
)
324 struct gpio_mockup_chip
*chips
;
325 struct device
*dev
= &pdev
->dev
;
326 int ret
, i
, base
, ngpio
;
329 if (gpio_mockup_params_nr
< 2)
332 chips
= devm_kzalloc(dev
,
333 sizeof(*chips
) * (gpio_mockup_params_nr
>> 1),
338 platform_set_drvdata(pdev
, chips
);
340 for (i
= 0; i
< gpio_mockup_params_nr
>> 1; i
++) {
341 base
= gpio_mockup_ranges
[i
* 2];
344 ngpio
= gpio_mockup_ranges
[i
* 2 + 1];
346 ngpio
= gpio_mockup_ranges
[i
* 2 + 1] - base
;
349 chip_name
= devm_kasprintf(dev
, GFP_KERNEL
,
350 "%s-%c", GPIO_MOCKUP_NAME
,
351 gpio_mockup_name_start
+ i
);
355 ret
= gpio_mockup_add(dev
, &chips
[i
],
356 chip_name
, base
, ngpio
);
362 dev_err(dev
, "gpio<%d..%d> add failed\n",
363 base
, base
< 0 ? ngpio
: base
+ ngpio
);
368 dev_info(dev
, "gpio<%d..%d> add successful!",
375 static int gpio_mockup_remove(struct platform_device
*pdev
)
377 struct gpio_mockup_chip
*chips
;
380 chips
= platform_get_drvdata(pdev
);
382 for (i
= 0; i
< gpio_mockup_params_nr
>> 1; i
++)
383 irq_free_descs(chips
[i
].gc
.irq_base
, chips
[i
].gc
.ngpio
);
388 static struct platform_driver gpio_mockup_driver
= {
390 .name
= GPIO_MOCKUP_NAME
,
392 .probe
= gpio_mockup_probe
,
393 .remove
= gpio_mockup_remove
,
396 static struct platform_device
*pdev
;
397 static int __init
mock_device_init(void)
401 gpio_mockup_dbg_dir
= debugfs_create_dir("gpio-mockup-event", NULL
);
402 if (!gpio_mockup_dbg_dir
)
403 pr_err("%s: error creating debugfs directory\n",
406 pdev
= platform_device_alloc(GPIO_MOCKUP_NAME
, -1);
410 err
= platform_device_add(pdev
);
412 platform_device_put(pdev
);
416 err
= platform_driver_register(&gpio_mockup_driver
);
418 platform_device_unregister(pdev
);
425 static void __exit
mock_device_exit(void)
427 debugfs_remove_recursive(gpio_mockup_dbg_dir
);
428 platform_driver_unregister(&gpio_mockup_driver
);
429 platform_device_unregister(pdev
);
432 module_init(mock_device_init
);
433 module_exit(mock_device_exit
);
435 MODULE_AUTHOR("Kamlakant Patel <kamlakant.patel@broadcom.com>");
436 MODULE_AUTHOR("Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>");
437 MODULE_DESCRIPTION("GPIO Testing driver");
438 MODULE_LICENSE("GPL v2");