2 * Kontron PLD GPIO driver
4 * Copyright (c) 2010-2013 Kontron Europe GmbH
5 * Author: Michael Brunner <michael.brunner@kontron.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License 2 as published
9 * by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/bitops.h>
21 #include <linux/errno.h>
22 #include <linux/platform_device.h>
23 #include <linux/gpio.h>
24 #include <linux/mfd/kempld.h>
26 #define KEMPLD_GPIO_MAX_NUM 16
27 #define KEMPLD_GPIO_MASK(x) (1 << ((x) % 8))
28 #define KEMPLD_GPIO_DIR_NUM(x) (0x40 + (x) / 8)
29 #define KEMPLD_GPIO_LVL_NUM(x) (0x42 + (x) / 8)
30 #define KEMPLD_GPIO_EVT_LVL_EDGE 0x46
31 #define KEMPLD_GPIO_IEN 0x4A
33 struct kempld_gpio_data
{
34 struct gpio_chip chip
;
35 struct kempld_device_data
*pld
;
39 * Set or clear GPIO bit
40 * kempld_get_mutex must be called prior to calling this function.
42 static void kempld_gpio_bitop(struct kempld_device_data
*pld
,
43 u8 reg
, u8 bit
, u8 val
)
47 status
= kempld_read8(pld
, reg
);
49 status
|= KEMPLD_GPIO_MASK(bit
);
51 status
&= ~KEMPLD_GPIO_MASK(bit
);
52 kempld_write8(pld
, reg
, status
);
55 static int kempld_gpio_get_bit(struct kempld_device_data
*pld
, u8 reg
, u8 bit
)
59 kempld_get_mutex(pld
);
60 status
= kempld_read8(pld
, reg
);
61 kempld_release_mutex(pld
);
63 return !!(status
& KEMPLD_GPIO_MASK(bit
));
66 static int kempld_gpio_get(struct gpio_chip
*chip
, unsigned offset
)
68 struct kempld_gpio_data
*gpio
69 = container_of(chip
, struct kempld_gpio_data
, chip
);
70 struct kempld_device_data
*pld
= gpio
->pld
;
72 return kempld_gpio_get_bit(pld
, KEMPLD_GPIO_LVL_NUM(offset
), offset
);
75 static void kempld_gpio_set(struct gpio_chip
*chip
, unsigned offset
, int value
)
77 struct kempld_gpio_data
*gpio
78 = container_of(chip
, struct kempld_gpio_data
, chip
);
79 struct kempld_device_data
*pld
= gpio
->pld
;
81 kempld_get_mutex(pld
);
82 kempld_gpio_bitop(pld
, KEMPLD_GPIO_LVL_NUM(offset
), offset
, value
);
83 kempld_release_mutex(pld
);
86 static int kempld_gpio_direction_input(struct gpio_chip
*chip
, unsigned offset
)
88 struct kempld_gpio_data
*gpio
89 = container_of(chip
, struct kempld_gpio_data
, chip
);
90 struct kempld_device_data
*pld
= gpio
->pld
;
92 kempld_get_mutex(pld
);
93 kempld_gpio_bitop(pld
, KEMPLD_GPIO_DIR_NUM(offset
), offset
, 0);
94 kempld_release_mutex(pld
);
99 static int kempld_gpio_direction_output(struct gpio_chip
*chip
, unsigned offset
,
102 struct kempld_gpio_data
*gpio
103 = container_of(chip
, struct kempld_gpio_data
, chip
);
104 struct kempld_device_data
*pld
= gpio
->pld
;
106 kempld_get_mutex(pld
);
107 kempld_gpio_bitop(pld
, KEMPLD_GPIO_LVL_NUM(offset
), offset
, value
);
108 kempld_gpio_bitop(pld
, KEMPLD_GPIO_DIR_NUM(offset
), offset
, 1);
109 kempld_release_mutex(pld
);
114 static int kempld_gpio_get_direction(struct gpio_chip
*chip
, unsigned offset
)
116 struct kempld_gpio_data
*gpio
117 = container_of(chip
, struct kempld_gpio_data
, chip
);
118 struct kempld_device_data
*pld
= gpio
->pld
;
120 return kempld_gpio_get_bit(pld
, KEMPLD_GPIO_DIR_NUM(offset
), offset
);
123 static int kempld_gpio_pincount(struct kempld_device_data
*pld
)
127 kempld_get_mutex(pld
);
129 /* Backup event register as it might be already initialized */
130 evt_back
= kempld_read16(pld
, KEMPLD_GPIO_EVT_LVL_EDGE
);
131 /* Clear event register */
132 kempld_write16(pld
, KEMPLD_GPIO_EVT_LVL_EDGE
, 0x0000);
133 /* Read back event register */
134 evt
= kempld_read16(pld
, KEMPLD_GPIO_EVT_LVL_EDGE
);
135 /* Restore event register */
136 kempld_write16(pld
, KEMPLD_GPIO_EVT_LVL_EDGE
, evt_back
);
138 kempld_release_mutex(pld
);
140 return evt
? __ffs(evt
) : 16;
143 static int kempld_gpio_probe(struct platform_device
*pdev
)
145 struct device
*dev
= &pdev
->dev
;
146 struct kempld_device_data
*pld
= dev_get_drvdata(dev
->parent
);
147 struct kempld_platform_data
*pdata
= dev_get_platdata(pld
->dev
);
148 struct kempld_gpio_data
*gpio
;
149 struct gpio_chip
*chip
;
152 if (pld
->info
.spec_major
< 2) {
154 "Driver only supports GPIO devices compatible to PLD spec. rev. 2.0 or higher\n");
158 gpio
= devm_kzalloc(dev
, sizeof(*gpio
), GFP_KERNEL
);
164 platform_set_drvdata(pdev
, gpio
);
167 chip
->label
= "gpio-kempld";
168 chip
->owner
= THIS_MODULE
;
171 if (pdata
&& pdata
->gpio_base
)
172 chip
->base
= pdata
->gpio_base
;
175 chip
->direction_input
= kempld_gpio_direction_input
;
176 chip
->direction_output
= kempld_gpio_direction_output
;
177 chip
->get_direction
= kempld_gpio_get_direction
;
178 chip
->get
= kempld_gpio_get
;
179 chip
->set
= kempld_gpio_set
;
180 chip
->ngpio
= kempld_gpio_pincount(pld
);
181 if (chip
->ngpio
== 0) {
182 dev_err(dev
, "No GPIO pins detected\n");
186 ret
= gpiochip_add(chip
);
188 dev_err(dev
, "Could not register GPIO chip\n");
192 dev_info(dev
, "GPIO functionality initialized with %d pins\n",
198 static int kempld_gpio_remove(struct platform_device
*pdev
)
200 struct kempld_gpio_data
*gpio
= platform_get_drvdata(pdev
);
202 return gpiochip_remove(&gpio
->chip
);
205 static struct platform_driver kempld_gpio_driver
= {
207 .name
= "kempld-gpio",
208 .owner
= THIS_MODULE
,
210 .probe
= kempld_gpio_probe
,
211 .remove
= kempld_gpio_remove
,
214 module_platform_driver(kempld_gpio_driver
);
216 MODULE_DESCRIPTION("KEM PLD GPIO Driver");
217 MODULE_AUTHOR("Michael Brunner <michael.brunner@kontron.com>");
218 MODULE_LICENSE("GPL");
219 MODULE_ALIAS("platform:gpio-kempld");