Jonathan Cameron | 930bae8 | 2009-08-18 18:06:31 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Industrial I/O - gpio based trigger support |
| 3 | * |
| 4 | * Copyright (c) 2008 Jonathan Cameron |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License version 2 as published by |
| 8 | * the Free Software Foundation. |
| 9 | * |
| 10 | * Currently this is more of a functioning proof of concept that a fully |
| 11 | * fledged trigger driver. |
| 12 | * |
| 13 | * TODO: |
| 14 | * |
| 15 | * Add board config elements to allow specification of startup settings. |
| 16 | * Add configuration settings (irq type etc) |
| 17 | */ |
| 18 | |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/platform_device.h> |
| 22 | #include <linux/interrupt.h> |
| 23 | #include <linux/gpio.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame^] | 24 | #include <linux/slab.h> |
Jonathan Cameron | 930bae8 | 2009-08-18 18:06:31 +0100 | [diff] [blame] | 25 | |
| 26 | #include "../iio.h" |
| 27 | #include "../trigger.h" |
| 28 | |
| 29 | LIST_HEAD(iio_gpio_trigger_list); |
| 30 | DEFINE_MUTEX(iio_gpio_trigger_list_lock); |
| 31 | |
| 32 | struct iio_gpio_trigger_info { |
| 33 | struct mutex in_use; |
| 34 | int gpio; |
| 35 | }; |
| 36 | /* |
| 37 | * Need to reference count these triggers and only enable gpio interrupts |
| 38 | * as appropriate. |
| 39 | */ |
| 40 | |
| 41 | /* So what functionality do we want in here?... */ |
| 42 | /* set high / low as interrupt type? */ |
| 43 | |
| 44 | static irqreturn_t iio_gpio_trigger_poll(int irq, void *private) |
| 45 | { |
| 46 | iio_trigger_poll(private); |
| 47 | return IRQ_HANDLED; |
| 48 | } |
| 49 | |
Randy Dunlap | 2fdec57 | 2009-08-21 13:59:08 -0700 | [diff] [blame] | 50 | static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL); |
Jonathan Cameron | 930bae8 | 2009-08-18 18:06:31 +0100 | [diff] [blame] | 51 | |
| 52 | static struct attribute *iio_gpio_trigger_attrs[] = { |
| 53 | &dev_attr_name.attr, |
| 54 | NULL, |
| 55 | }; |
| 56 | |
| 57 | static const struct attribute_group iio_gpio_trigger_attr_group = { |
| 58 | .attrs = iio_gpio_trigger_attrs, |
| 59 | }; |
| 60 | |
| 61 | static int iio_gpio_trigger_probe(struct platform_device *dev) |
| 62 | { |
| 63 | int *pdata = dev->dev.platform_data; |
| 64 | struct iio_gpio_trigger_info *trig_info; |
| 65 | struct iio_trigger *trig, *trig2; |
| 66 | int i, irq, ret = 0; |
| 67 | if (!pdata) { |
| 68 | printk(KERN_ERR "No IIO gpio trigger platform data found\n"); |
| 69 | goto error_ret; |
| 70 | } |
| 71 | for (i = 0;; i++) { |
| 72 | if (!gpio_is_valid(pdata[i])) |
| 73 | break; |
| 74 | trig = iio_allocate_trigger(); |
| 75 | if (!trig) { |
| 76 | ret = -ENOMEM; |
| 77 | goto error_free_completed_registrations; |
| 78 | } |
| 79 | |
| 80 | trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL); |
| 81 | if (!trig_info) { |
| 82 | ret = -ENOMEM; |
| 83 | goto error_put_trigger; |
| 84 | } |
| 85 | trig->control_attrs = &iio_gpio_trigger_attr_group; |
| 86 | trig->private_data = trig_info; |
| 87 | trig_info->gpio = pdata[i]; |
| 88 | trig->owner = THIS_MODULE; |
| 89 | trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL); |
| 90 | if (!trig->name) { |
| 91 | ret = -ENOMEM; |
| 92 | goto error_free_trig_info; |
| 93 | } |
| 94 | snprintf((char *)trig->name, |
| 95 | IIO_TRIGGER_NAME_LENGTH, |
| 96 | "gpiotrig%d", |
| 97 | pdata[i]); |
| 98 | ret = gpio_request(trig_info->gpio, trig->name); |
| 99 | if (ret) |
| 100 | goto error_free_name; |
| 101 | |
| 102 | ret = gpio_direction_input(trig_info->gpio); |
| 103 | if (ret) |
| 104 | goto error_release_gpio; |
| 105 | |
| 106 | irq = gpio_to_irq(trig_info->gpio); |
| 107 | if (irq < 0) { |
| 108 | ret = irq; |
| 109 | goto error_release_gpio; |
| 110 | } |
| 111 | |
| 112 | ret = request_irq(irq, iio_gpio_trigger_poll, |
| 113 | IRQF_TRIGGER_RISING, |
| 114 | trig->name, |
| 115 | trig); |
| 116 | if (ret) |
| 117 | goto error_release_gpio; |
| 118 | |
| 119 | ret = iio_trigger_register(trig); |
| 120 | if (ret) |
| 121 | goto error_release_irq; |
| 122 | |
| 123 | list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list); |
| 124 | |
| 125 | } |
| 126 | return 0; |
| 127 | |
| 128 | /* First clean up the partly allocated trigger */ |
| 129 | error_release_irq: |
| 130 | free_irq(irq, trig); |
| 131 | error_release_gpio: |
| 132 | gpio_free(trig_info->gpio); |
| 133 | error_free_name: |
| 134 | kfree(trig->name); |
| 135 | error_free_trig_info: |
| 136 | kfree(trig_info); |
| 137 | error_put_trigger: |
| 138 | iio_put_trigger(trig); |
| 139 | error_free_completed_registrations: |
| 140 | /* The rest should have been added to the iio_gpio_trigger_list */ |
| 141 | list_for_each_entry_safe(trig, |
| 142 | trig2, |
| 143 | &iio_gpio_trigger_list, |
| 144 | alloc_list) { |
| 145 | trig_info = trig->private_data; |
| 146 | free_irq(gpio_to_irq(trig_info->gpio), trig); |
| 147 | gpio_free(trig_info->gpio); |
| 148 | kfree(trig->name); |
| 149 | kfree(trig_info); |
| 150 | iio_trigger_unregister(trig); |
| 151 | } |
| 152 | |
| 153 | error_ret: |
| 154 | return ret; |
| 155 | } |
| 156 | |
| 157 | static int iio_gpio_trigger_remove(struct platform_device *dev) |
| 158 | { |
| 159 | struct iio_trigger *trig, *trig2; |
| 160 | struct iio_gpio_trigger_info *trig_info; |
| 161 | |
| 162 | mutex_lock(&iio_gpio_trigger_list_lock); |
| 163 | list_for_each_entry_safe(trig, |
| 164 | trig2, |
| 165 | &iio_gpio_trigger_list, |
| 166 | alloc_list) { |
| 167 | trig_info = trig->private_data; |
| 168 | iio_trigger_unregister(trig); |
| 169 | free_irq(gpio_to_irq(trig_info->gpio), trig); |
| 170 | gpio_free(trig_info->gpio); |
| 171 | kfree(trig->name); |
| 172 | kfree(trig_info); |
| 173 | iio_put_trigger(trig); |
| 174 | } |
| 175 | mutex_unlock(&iio_gpio_trigger_list_lock); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | static struct platform_driver iio_gpio_trigger_driver = { |
| 181 | .probe = iio_gpio_trigger_probe, |
| 182 | .remove = iio_gpio_trigger_remove, |
| 183 | .driver = { |
| 184 | .name = "iio_gpio_trigger", |
| 185 | .owner = THIS_MODULE, |
| 186 | }, |
| 187 | }; |
| 188 | |
| 189 | static int __init iio_gpio_trig_init(void) |
| 190 | { |
| 191 | return platform_driver_register(&iio_gpio_trigger_driver); |
| 192 | } |
| 193 | module_init(iio_gpio_trig_init); |
| 194 | |
| 195 | static void __exit iio_gpio_trig_exit(void) |
| 196 | { |
| 197 | platform_driver_unregister(&iio_gpio_trigger_driver); |
| 198 | } |
| 199 | module_exit(iio_gpio_trig_exit); |
| 200 | |
| 201 | MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); |
| 202 | MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem"); |
| 203 | MODULE_LICENSE("GPL v2"); |