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141 lines
3.3 KiB
141 lines
3.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright 2016 Jonathan Cameron <[email protected]> |
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* |
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* Based on a mashup of the hrtimer trigger and continuous sampling proposal of |
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* Gregor Boirie <[email protected]> |
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* |
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* Note this is still rather experimental and may eat babies. |
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* |
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* Todo |
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* * Protect against connection of devices that 'need' the top half |
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* handler. |
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* * Work out how to run top half handlers in this context if it is |
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* safe to do so (timestamp grabbing for example) |
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* |
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* Tested against a max1363. Used about 33% cpu for the thread and 20% |
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* for generic_buffer piping to /dev/null. Watermark set at 64 on a 128 |
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* element kfifo buffer. |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/irq_work.h> |
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#include <linux/kthread.h> |
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#include <linux/freezer.h> |
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#include <linux/iio/iio.h> |
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#include <linux/iio/trigger.h> |
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#include <linux/iio/sw_trigger.h> |
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struct iio_loop_info { |
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struct iio_sw_trigger swt; |
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struct task_struct *task; |
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}; |
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static const struct config_item_type iio_loop_type = { |
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.ct_owner = THIS_MODULE, |
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}; |
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static int iio_loop_thread(void *data) |
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{ |
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struct iio_trigger *trig = data; |
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set_freezable(); |
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do { |
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iio_trigger_poll_chained(trig); |
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} while (likely(!kthread_freezable_should_stop(NULL))); |
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return 0; |
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} |
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static int iio_loop_trigger_set_state(struct iio_trigger *trig, bool state) |
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{ |
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struct iio_loop_info *loop_trig = iio_trigger_get_drvdata(trig); |
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if (state) { |
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loop_trig->task = kthread_run(iio_loop_thread, |
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trig, trig->name); |
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if (IS_ERR(loop_trig->task)) { |
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dev_err(&trig->dev, |
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"failed to create trigger loop thread\n"); |
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return PTR_ERR(loop_trig->task); |
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} |
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} else { |
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kthread_stop(loop_trig->task); |
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} |
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return 0; |
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} |
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static const struct iio_trigger_ops iio_loop_trigger_ops = { |
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.set_trigger_state = iio_loop_trigger_set_state, |
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}; |
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static struct iio_sw_trigger *iio_trig_loop_probe(const char *name) |
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{ |
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struct iio_loop_info *trig_info; |
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int ret; |
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trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL); |
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if (!trig_info) |
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return ERR_PTR(-ENOMEM); |
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trig_info->swt.trigger = iio_trigger_alloc(NULL, "%s", name); |
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if (!trig_info->swt.trigger) { |
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ret = -ENOMEM; |
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goto err_free_trig_info; |
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} |
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iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info); |
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trig_info->swt.trigger->ops = &iio_loop_trigger_ops; |
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ret = iio_trigger_register(trig_info->swt.trigger); |
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if (ret) |
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goto err_free_trigger; |
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iio_swt_group_init_type_name(&trig_info->swt, name, &iio_loop_type); |
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return &trig_info->swt; |
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err_free_trigger: |
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iio_trigger_free(trig_info->swt.trigger); |
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err_free_trig_info: |
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kfree(trig_info); |
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return ERR_PTR(ret); |
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} |
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static int iio_trig_loop_remove(struct iio_sw_trigger *swt) |
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{ |
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struct iio_loop_info *trig_info; |
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trig_info = iio_trigger_get_drvdata(swt->trigger); |
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iio_trigger_unregister(swt->trigger); |
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iio_trigger_free(swt->trigger); |
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kfree(trig_info); |
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return 0; |
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} |
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static const struct iio_sw_trigger_ops iio_trig_loop_ops = { |
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.probe = iio_trig_loop_probe, |
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.remove = iio_trig_loop_remove, |
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}; |
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static struct iio_sw_trigger_type iio_trig_loop = { |
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.name = "loop", |
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.owner = THIS_MODULE, |
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.ops = &iio_trig_loop_ops, |
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}; |
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module_iio_sw_trigger_driver(iio_trig_loop); |
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MODULE_AUTHOR("Jonathan Cameron <[email protected]>"); |
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MODULE_DESCRIPTION("Loop based trigger for the iio subsystem"); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_ALIAS("platform:iio-trig-loop");
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