Staging: IIO: max1363 add software ring buffer support using ring_sw (0a1231df) · Commits · e / devices / android_kernel_fairphone_FP3

drivers/staging/iio/adc/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -3,5 +3,6 @@
		#

		max1363-y := max1363_core.o
		max1363-$(CONFIG_IIO_RING_BUFFER) += max1363_ring.o

		obj-$(CONFIG_MAX1363) += max1363.o

drivers/staging/iio/adc/max1363.h

+13 −1

Original line number	Diff line number	Diff line
		@@ -228,6 +228,18 @@ struct max1363_state {
		struct iio_trigger *trig;
		struct regulator *reg;
		};
		#ifdef CONFIG_IIO_RING_BUFFER

		ssize_t max1363_scan_from_ring(struct device *dev,
		struct device_attribute *attr,
		char *buf);
		int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev);
		void max1363_ring_cleanup(struct iio_dev *indio_dev);

		int max1363_initialize_ring(struct iio_ring_buffer *ring);
		void max1363_uninitialize_ring(struct iio_ring_buffer *ring);

		#else /* CONFIG_IIO_RING_BUFFER */

		static inline void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
		{
		@@ -253,5 +265,5 @@ max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
		};

		static inline void max1363_ring_cleanup(struct iio_dev *indio_dev) {};

		#endif /* CONFIG_IIO_RING_BUFFER */
		#endif /* _MAX1363_H_ */

drivers/staging/iio/adc/max1363_ring.c

0 → 100644

+241 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2008 Jonathan Cameron
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*
		* max1363_ring.c
		*/

		#include <linux/interrupt.h>
		#include <linux/gpio.h>
		#include <linux/workqueue.h>
		#include <linux/device.h>
		#include <linux/kernel.h>
		#include <linux/sysfs.h>
		#include <linux/list.h>
		#include <linux/i2c.h>

		#include "../iio.h"
		#include "../ring_generic.h"
		#include "../ring_sw.h"
		#include "../trigger.h"
		#include "../sysfs.h"

		#include "max1363.h"

		ssize_t max1363_scan_from_ring(struct device *dev,
		struct device_attribute *attr,
		char *buf)
		{
		struct iio_dev *dev_info = dev_get_drvdata(dev);
		struct max1363_state *info = dev_info->dev_data;
		int i, ret, len = 0;
		char *ring_data;

		ring_data = kmalloc(info->current_mode->numvals*2, GFP_KERNEL);
		if (ring_data == NULL) {
		ret = -ENOMEM;
		goto error_ret;
		}
		ret = dev_info->ring->access.read_last(dev_info->ring, ring_data);
		if (ret)
		goto error_free_ring_data;
		len += sprintf(buf+len, "ring ");
		for (i = 0; i < info->current_mode->numvals; i++)
		len += sprintf(buf + len, "%d ",
		((int)(ring_data[i*2 + 0] & 0x0F) << 8)
		+ ((int)(ring_data[i*2 + 1])));
		len += sprintf(buf + len, "\n");
		kfree(ring_data);

		return len;

		error_free_ring_data:
		kfree(ring_data);
		error_ret:
		return ret;
		}

		/**
		* max1363_ring_preenable() setup the parameters of the ring before enabling
		*
		* The complex nature of the setting of the nuber of bytes per datum is due
		* to this driver currently ensuring that the timestamp is stored at an 8
		* byte boundary.
		**/
		static int max1363_ring_preenable(struct iio_dev *indio_dev)
		{
		struct max1363_state *st = indio_dev->dev_data;
		size_t d_size;

		if (indio_dev->ring->access.set_bpd) {
		d_size = st->current_mode->numvals*2 + sizeof(s64);
		if (d_size % 8)
		d_size += 8 - (d_size % 8);
		indio_dev->ring->access.set_bpd(indio_dev->ring, d_size);
		}

		return 0;
		}

		/**
		* max1363_ring_postenable() typical ring post enable
		*
		* Only not moved into the core for the hardware ring buffer cases
		* that are more sophisticated.
		**/
		static int max1363_ring_postenable(struct iio_dev *indio_dev)
		{
		if (indio_dev->trig == NULL)
		return 0;
		return iio_trigger_attach_poll_func(indio_dev->trig,
		indio_dev->pollfunc);
		}

		/**
		* max1363_ring_predisable() runs just prior to ring buffer being disabled
		*
		* Typical predisable function which ensures that no trigger events can
		* occur before we disable the ring buffer (and hence would have no idea
		* what to do with them)
		**/
		static int max1363_ring_predisable(struct iio_dev *indio_dev)
		{
		if (indio_dev->trig)
		return iio_trigger_dettach_poll_func(indio_dev->trig,
		indio_dev->pollfunc);
		else
		return 0;
		}

		/**
		* max1363_poll_func_th() th of trigger launched polling to ring buffer
		*
		* As sampling only occurs on i2c comms occuring, leave timestamping until
		* then. Some triggers will generate their own time stamp. Currently
		* there is no way of notifying them when no one cares.
		**/
		void max1363_poll_func_th(struct iio_dev *indio_dev)
		{
		struct max1363_state *st = indio_dev->dev_data;

		schedule_work(&st->poll_work);

		return;
		}
		/**
		* max1363_poll_bh_to_ring() bh of trigger launched polling to ring buffer
		* @work_s: the work struct through which this was scheduled
		*
		* Currently there is no option in this driver to disable the saving of
		* timestamps within the ring.
		* I think the one copy of this at a time was to avoid problems if the
		* trigger was set far too high and the reads then locked up the computer.
		**/
		static void max1363_poll_bh_to_ring(struct work_struct *work_s)
		{
		struct max1363_state *st = container_of(work_s, struct max1363_state,
		poll_work);
		struct iio_dev *indio_dev = st->indio_dev;
		struct iio_sw_ring_buffer *ring = iio_to_sw_ring(indio_dev->ring);
		s64 time_ns;
		__u8 *rxbuf;
		int b_sent;
		size_t d_size;

		/* Ensure the timestamp is 8 byte aligned */
		d_size = st->current_mode->numvals*2 + sizeof(s64);
		if (d_size % sizeof(s64))
		d_size += sizeof(s64) - (d_size % sizeof(s64));

		/* Ensure only one copy of this function running at a time */
		if (atomic_inc_return(&st->protect_ring) > 1)
		return;

		/* Monitor mode prevents reading. Whilst not currently implemented
		* might as well have this test in here in the meantime as it does
		* no harm.
		*/
		if (st->current_mode->numvals == 0)
		return;

		rxbuf = kmalloc(d_size, GFP_KERNEL);
		if (rxbuf == NULL)
		return;

		b_sent = i2c_master_recv(st->client,
		rxbuf,
		st->current_mode->numvals*2);
		if (b_sent < 0)
		goto done;

		time_ns = iio_get_time_ns();

		memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));

		indio_dev->ring->access.store_to(&ring->buf, rxbuf, time_ns);
		done:
		kfree(rxbuf);
		atomic_dec(&st->protect_ring);
		}


		int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
		{
		struct max1363_state *st = indio_dev->dev_data;
		int ret = 0;

		indio_dev->ring = iio_sw_rb_allocate(indio_dev);
		if (!indio_dev->ring) {
		ret = -ENOMEM;
		goto error_ret;
		}
		/* Effectively select the ring buffer implementation */
		iio_ring_sw_register_funcs(&st->indio_dev->ring->access);
		indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
		if (indio_dev->pollfunc == NULL) {
		ret = -ENOMEM;
		goto error_deallocate_sw_rb;
		}
		/* Configure the polling function called on trigger interrupts */
		indio_dev->pollfunc->poll_func_main = &max1363_poll_func_th;
		indio_dev->pollfunc->private_data = indio_dev;

		/* Ring buffer functions - here trigger setup related */
		indio_dev->ring->postenable = &max1363_ring_postenable;
		indio_dev->ring->preenable = &max1363_ring_preenable;
		indio_dev->ring->predisable = &max1363_ring_predisable;
		INIT_WORK(&st->poll_work, &max1363_poll_bh_to_ring);

		/* Flag that polled ring buffering is possible */
		indio_dev->modes \|= INDIO_RING_TRIGGERED;
		return 0;
		error_deallocate_sw_rb:
		iio_sw_rb_free(indio_dev->ring);
		error_ret:
		return ret;
		}

		void max1363_ring_cleanup(struct iio_dev *indio_dev)
		{
		/* ensure that the trigger has been detached */
		if (indio_dev->trig) {
		iio_put_trigger(indio_dev->trig);
		iio_trigger_dettach_poll_func(indio_dev->trig,
		indio_dev->pollfunc);
		}
		kfree(indio_dev->pollfunc);
		iio_sw_rb_free(indio_dev->ring);
		}

		void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
		{
		iio_ring_buffer_unregister(ring);
		};

		int max1363_initialize_ring(struct iio_ring_buffer *ring)
		{
		return iio_ring_buffer_register(ring);
		};