[PATCH v5] media: video-i2c: add video-i2c driver

[Matt Ranostay <matt@ranostay.consulting>]

There are several thermal sensors that only have a low-speed bus
interface but output valid video data. This patchset enables support
for the AMG88xx "Grid-Eye" sensor family.

Cc: Attila Kinali <attila@kinali.ch>
Cc: Marek Vasut <marex@denx.de>
Cc: Luca Barbato <lu_zero@gentoo.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
---
Changes from v1:
* correct i2c_polling_remove() operations
* fixed delay calcuation in buffer_queue()
* add include linux/slab.h

Changes from v2:
* fix build error due to typo in include of slab.h

Changes from v3:
* switch data transport to a kthread to avoid to .buf_queue that can't sleep
* change naming from i2c-polling to video-i2c
* make the driver for single chipset under another uses the driver

Changes from v4:
* fix wraparound issue with jiffies and schedule_timeout_interruptible() 

 drivers/media/i2c/Kconfig     |   9 +
 drivers/media/i2c/Makefile    |   1 +
 drivers/media/i2c/video-i2c.c | 569 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 579 insertions(+)
 create mode 100644 drivers/media/i2c/video-i2c.c

diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index b31fa6fae009..ef84715293a9 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -768,6 +768,15 @@ config VIDEO_M52790
 
 	 To compile this driver as a module, choose M here: the
 	 module will be called m52790.
+
+config VIDEO_I2C
+	tristate "I2C transport video support"
+	depends on VIDEO_V4L2 && I2C
+	select VIDEOBUF2_VMALLOC
+	---help---
+	  Enable the I2C transport video support which supports the
+	  following:
+	   * Panasonic AMG88xx Grid-Eye Sensors
 endmenu
 
 menu "Sensors used on soc_camera driver"
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index 92773b2e6225..7c8eeb213c3b 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -79,6 +79,7 @@ obj-$(CONFIG_VIDEO_LM3646)	+= lm3646.o
 obj-$(CONFIG_VIDEO_SMIAPP_PLL)	+= smiapp-pll.o
 obj-$(CONFIG_VIDEO_AK881X)		+= ak881x.o
 obj-$(CONFIG_VIDEO_IR_I2C)  += ir-kbd-i2c.o
+obj-$(CONFIG_VIDEO_I2C)		+= video-i2c.o
 obj-$(CONFIG_VIDEO_ML86V7667)	+= ml86v7667.o
 obj-$(CONFIG_VIDEO_OV2659)	+= ov2659.o
 obj-$(CONFIG_VIDEO_TC358743)	+= tc358743.o
diff --git a/drivers/media/i2c/video-i2c.c b/drivers/media/i2c/video-i2c.c
new file mode 100644
index 000000000000..9390560bd117
--- /dev/null
+++ b/drivers/media/i2c/video-i2c.c
@@ -0,0 +1,569 @@
+/*
+ * video-i2c.c - Support for I2C transport video devices
+ *
+ * Copyright (C) 2016 Matt Ranostay <mranostay@ranostay.consulting>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Supported:
+ * - Panasonic AMG88xx Grid-Eye Sensors
+ */
+
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/i2c.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-common.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fh.h>
+#include <media/v4l2-event.h>
+#include <media/videobuf2-v4l2.h>
+#include <media/videobuf2-vmalloc.h>
+
+#define VIDEO_I2C_DRIVER	"video-i2c"
+#define MAX_BUFFER_SIZE		128
+
+struct video_i2c_chip;
+
+struct video_i2c_buffer {
+	struct vb2_v4l2_buffer vb;
+	struct list_head list;
+};
+
+struct video_i2c_data {
+	struct i2c_client *client;
+	const struct video_i2c_chip *chip;
+	struct mutex lock;
+	spinlock_t slock;
+	struct mutex queue_lock;
+
+	struct v4l2_device v4l2_dev;
+	struct video_device vdev;
+	struct vb2_queue vb_vidq;
+
+	struct task_struct *kthread_vid_cap;
+	struct list_head vid_cap_active;
+};
+
+static struct v4l2_fmtdesc amg88xx_format = {
+	.description = "12-bit Greyscale",
+	.pixelformat = V4L2_PIX_FMT_Y12,
+};
+
+static struct v4l2_frmsize_discrete amg88xx_size = {
+	.width = 8,
+	.height = 8,
+};
+
+struct video_i2c_chip {
+	/* video dimensions */
+	struct v4l2_fmtdesc *format;
+	struct v4l2_frmsize_discrete *size;
+
+	/* max frames per second */
+	unsigned int max_fps;
+
+	/* pixel buffer size */
+	unsigned int buffer_size;
+
+	/* pixel size in bits */
+	unsigned int bpp;
+
+	/* xfer function */
+	int (*xfer)(struct video_i2c_data *data, char *buf);
+};
+
+static int amg88xx_xfer(struct video_i2c_data *data, char *buf)
+{
+	struct i2c_client *client = data->client;
+	struct i2c_msg msg[2];
+	u8 reg = 0x80;
+	int ret;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = 0;
+	msg[0].len = 1;
+	msg[0].buf  = (char *) &reg;
+
+	msg[1].addr = client->addr;
+	msg[1].flags = I2C_M_RD;
+	msg[1].len = data->chip->buffer_size;
+	msg[1].buf = (char *) buf;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+
+	return (ret == 2) ? 0 : -EIO;
+}
+
+static const struct video_i2c_chip video_i2c_chip = {
+	.size		= &amg88xx_size,
+	.format		= &amg88xx_format,
+	.max_fps	= 10,
+	.buffer_size	= 128,
+	.bpp		= 16,
+	.xfer		= &amg88xx_xfer,
+};
+
+static const struct v4l2_file_operations video_i2c_fops = {
+	.owner		= THIS_MODULE,
+	.open		= v4l2_fh_open,
+	.release	= vb2_fop_release,
+	.poll		= vb2_fop_poll,
+	.read		= vb2_fop_read,
+	.mmap		= vb2_fop_mmap,
+	.unlocked_ioctl = video_ioctl2,
+};
+
+static int queue_setup(struct vb2_queue *vq,
+		       unsigned int *nbuffers, unsigned int *nplanes,
+		       unsigned int sizes[], struct device *alloc_devs[])
+{
+	struct video_i2c_data *data = vb2_get_drv_priv(vq);
+	unsigned int size = data->chip->buffer_size;
+
+	if (vq->num_buffers + *nbuffers < 2)
+		*nbuffers = 2;
+
+	if (*nplanes)
+		return sizes[0] < size ? -EINVAL : 0;
+
+	*nplanes = 1;
+	sizes[0] = size;
+
+	return 0;
+}
+
+static int buffer_prepare(struct vb2_buffer *vb)
+{
+	struct video_i2c_data *data = vb2_get_drv_priv(vb->vb2_queue);
+	unsigned int size = data->chip->buffer_size;
+
+	if (vb2_plane_size(vb, 0) < size)
+		return -EINVAL;
+
+	vb2_set_plane_payload(vb, 0, size);
+
+	return 0;
+}
+
+static void buffer_queue(struct vb2_buffer *vb)
+{
+	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
+	struct video_i2c_data *data = vb2_get_drv_priv(vb->vb2_queue);
+	struct video_i2c_buffer *buf =
+			container_of(vbuf, struct video_i2c_buffer, vb);
+
+	spin_lock(&data->slock);
+	list_add_tail(&buf->list, &data->vid_cap_active);
+	spin_unlock(&data->slock);
+}
+
+static int video_i2c_thread_vid_cap(void *priv)
+{
+	struct video_i2c_data *data = priv;
+	struct video_i2c_buffer *vid_cap_buf = NULL;
+
+	set_freezable();
+
+	do {
+		unsigned int start_jiffies = jiffies;
+		unsigned int delay = msecs_to_jiffies(1000 / data->chip->max_fps);
+		int schedule_delay;
+
+		try_to_freeze();
+
+		mutex_lock(&data->lock);
+		spin_lock(&data->slock);
+
+		if (!list_empty(&data->vid_cap_active)) {
+			vid_cap_buf = list_entry(data->vid_cap_active.next,
+						 struct video_i2c_buffer, list);
+			list_del(&vid_cap_buf->list);
+		}
+
+		if (vid_cap_buf) {
+			struct vb2_buffer *vb2_buf = &vid_cap_buf->vb.vb2_buf;
+			void *vbuf = vb2_plane_vaddr(vb2_buf, 0);
+			int ret = data->chip->xfer(data, vbuf);
+
+			vb2_buf->timestamp = ktime_get_ns();
+			vb2_buffer_done(vb2_buf, ret ?
+					VB2_BUF_STATE_ERROR : VB2_BUF_STATE_DONE);
+		}
+
+		spin_unlock(&data->slock);
+		mutex_unlock(&data->lock);
+
+		schedule_delay = delay - (jiffies - start_jiffies);
+
+		if (schedule_delay < 0)
+			schedule_delay = delay;
+
+		schedule_timeout_interruptible(schedule_delay);
+	} while (!kthread_should_stop());
+
+	return 0;
+}
+
+static int start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+	struct video_i2c_data *data = vb2_get_drv_priv(vq);
+
+	if (data->kthread_vid_cap)
+		return 0;
+
+	data->kthread_vid_cap = kthread_run(video_i2c_thread_vid_cap, data,
+					    "%s-vid-cap", data->v4l2_dev.name);
+
+	if (IS_ERR(data->kthread_vid_cap)) {
+		struct video_i2c_buffer *buf, *tmp;
+
+		list_for_each_entry_safe(buf, tmp, &data->vid_cap_active, list) {
+			list_del(&buf->list);
+			vb2_buffer_done(&buf->vb.vb2_buf,
+					VB2_BUF_STATE_QUEUED);
+		}
+
+		return PTR_ERR(data->kthread_vid_cap);
+	}
+
+	return 0;
+}
+
+static void stop_streaming(struct vb2_queue *vq)
+{
+	struct video_i2c_data *data = vb2_get_drv_priv(vq);
+
+	if (data->kthread_vid_cap == NULL)
+		return;
+
+	mutex_lock(&data->lock);
+	spin_lock(&data->slock);
+
+	while (!list_empty(&data->vid_cap_active)) {
+		struct video_i2c_buffer *buf;
+
+		buf = list_entry(data->vid_cap_active.next,
+				 struct video_i2c_buffer, list);
+		list_del(&buf->list);
+		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
+	}
+	spin_unlock(&data->slock);
+	mutex_unlock(&data->lock);
+
+	kthread_stop(data->kthread_vid_cap);
+
+	data->kthread_vid_cap = NULL;
+}
+
+static struct vb2_ops video_i2c_video_qops = {
+	.queue_setup		= queue_setup,
+	.buf_prepare		= buffer_prepare,
+	.buf_queue		= buffer_queue,
+	.start_streaming	= start_streaming,
+	.stop_streaming		= stop_streaming,
+	.wait_prepare		= vb2_ops_wait_prepare,
+	.wait_finish		= vb2_ops_wait_finish,
+};
+
+static int video_i2c_querycap(struct file *file, void  *priv,
+				struct v4l2_capability *vcap)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	struct i2c_client *client = data->client;
+
+	strlcpy(vcap->driver, data->v4l2_dev.name, sizeof(vcap->driver));
+	strlcpy(vcap->card, "I2C Transport Video", sizeof(vcap->card));
+
+	sprintf(vcap->bus_info, "I2C:%d-%d", client->adapter->nr, client->addr);
+	return 0;
+}
+
+static int video_i2c_g_input(struct file *file, void *fh, unsigned int *inp)
+{
+	*inp = 0;
+
+	return 0;
+}
+
+static int video_i2c_s_input(struct file *file, void *fh, unsigned int inp)
+{
+	return (inp > 0) ? -EINVAL : 0;
+}
+
+static int video_i2c_enum_input(struct file *file, void *fh,
+				  struct v4l2_input *vin)
+{
+	if (vin->index > 0)
+		return -EINVAL;
+
+	strlcpy(vin->name, "Camera", sizeof(vin->name));
+
+	vin->type = V4L2_INPUT_TYPE_CAMERA;
+	vin->audioset = 0;
+	vin->tuner = 0;
+	vin->std = 0;
+	vin->status = 0;
+
+	return 0;
+}
+
+static int video_i2c_enum_fmt_vid_cap(struct file *file, void *fh,
+					struct v4l2_fmtdesc *fmt)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	enum v4l2_buf_type type = fmt->type;
+
+	if (fmt->index > 0)
+		return -EINVAL;
+
+	*fmt = *data->chip->format;
+	fmt->type = type;
+
+	return 0;
+}
+
+static int video_i2c_enum_framesizes(struct file *file, void *fh,
+				       struct v4l2_frmsizeenum *fsize)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	struct v4l2_frmsize_discrete *size = data->chip->size;
+
+	/* currently only one frame size is allowed */
+	if (fsize->index > 0)
+		return -EINVAL;
+
+	if (fsize->pixel_format != data->chip->format->pixelformat)
+		return -EINVAL;
+
+	fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
+	fsize->discrete.width = size->width;
+	fsize->discrete.height = size->height;
+
+	return 0;
+}
+
+static int video_i2c_enum_frameintervals(struct file *file, void *priv,
+					   struct v4l2_frmivalenum *fe)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	struct v4l2_frmsize_discrete *size = data->chip->size;
+
+	if (fe->index > 0)
+		return -EINVAL;
+
+	if ((fe->width != size->width) || (fe->height != size->height))
+		return -EINVAL;
+
+	fe->type = V4L2_FRMIVAL_TYPE_DISCRETE;
+	fe->discrete.numerator = 1;
+	fe->discrete.denominator = data->chip->max_fps;
+
+	return 0;
+}
+
+static int video_i2c_try_fmt_vid_cap(struct file *file, void *fh,
+				       struct v4l2_format *fmt)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	struct v4l2_pix_format *pix = &fmt->fmt.pix;
+	struct v4l2_frmsize_discrete *size = data->chip->size;
+	unsigned int bpp = data->chip->bpp / 8;
+
+	pix->width = size->width;
+	pix->height = size->height;
+	pix->pixelformat = data->chip->format->pixelformat;
+	pix->field = V4L2_FIELD_NONE;
+	pix->bytesperline = pix->width * bpp;
+	pix->sizeimage = pix->width * pix->height * bpp;
+	pix->colorspace = V4L2_COLORSPACE_SRGB;
+	pix->priv = 0;
+
+	return 0;
+}
+
+static int video_i2c_fmt_vid_cap(struct file *file, void *fh,
+				     struct v4l2_format *fmt)
+{
+	struct video_i2c_data *data = video_drvdata(file);
+	int ret = video_i2c_try_fmt_vid_cap(file, fh, fmt);
+
+	if (ret < 0)
+		return ret;
+
+	if (vb2_is_busy(&data->vb_vidq))
+		return -EBUSY;
+
+	return 0;
+}
+
+static int video_i2c_g_parm(struct file *filp, void *priv,
+			      struct v4l2_streamparm *parm)
+{
+	struct video_i2c_data *data = video_drvdata(filp);
+
+	if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	parm->parm.capture.readbuffers = 1;
+	parm->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
+	parm->parm.capture.timeperframe.numerator = 1;
+	parm->parm.capture.timeperframe.denominator = data->chip->max_fps;
+
+	return 0;
+}
+
+static int video_i2c_s_parm(struct file *filp, void *priv,
+			      struct v4l2_streamparm *parm)
+{
+	if (parm->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	return video_i2c_g_parm(filp, priv, parm);
+}
+
+static const struct v4l2_ioctl_ops video_i2c_ioctl_ops = {
+	.vidioc_querycap		= video_i2c_querycap,
+	.vidioc_g_input			= video_i2c_g_input,
+	.vidioc_s_input			= video_i2c_s_input,
+	.vidioc_enum_input		= video_i2c_enum_input,
+	.vidioc_enum_fmt_vid_cap	= video_i2c_enum_fmt_vid_cap,
+	.vidioc_enum_framesizes		= video_i2c_enum_framesizes,
+	.vidioc_enum_frameintervals	= video_i2c_enum_frameintervals,
+	.vidioc_g_fmt_vid_cap		= video_i2c_try_fmt_vid_cap,
+	.vidioc_s_fmt_vid_cap		= video_i2c_fmt_vid_cap,
+	.vidioc_g_parm			= video_i2c_g_parm,
+	.vidioc_s_parm			= video_i2c_s_parm,
+	.vidioc_try_fmt_vid_cap		= video_i2c_try_fmt_vid_cap,
+	.vidioc_reqbufs			= vb2_ioctl_reqbufs,
+	.vidioc_create_bufs		= vb2_ioctl_create_bufs,
+	.vidioc_prepare_buf		= vb2_ioctl_prepare_buf,
+	.vidioc_querybuf		= vb2_ioctl_querybuf,
+	.vidioc_qbuf			= vb2_ioctl_qbuf,
+	.vidioc_dqbuf			= vb2_ioctl_dqbuf,
+	.vidioc_streamon		= vb2_ioctl_streamon,
+	.vidioc_streamoff		= vb2_ioctl_streamoff,
+};
+
+static void video_i2c_release(struct video_device *vdev)
+{
+	kfree(video_get_drvdata(vdev));
+}
+
+static int video_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct video_i2c_data *data;
+	struct v4l2_device *v4l2_dev;
+	struct vb2_queue *queue;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->chip = &video_i2c_chip;
+	data->client = client;
+	v4l2_dev = &data->v4l2_dev;
+	strlcpy(v4l2_dev->name, VIDEO_I2C_DRIVER, sizeof(v4l2_dev->name));
+
+	ret = v4l2_device_register(&client->dev, v4l2_dev);
+	if (ret < 0)
+		goto error_free_device;
+
+	mutex_init(&data->lock);
+	mutex_init(&data->queue_lock);
+
+	queue = &data->vb_vidq;
+	queue->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+	queue->io_modes = VB2_MMAP | VB2_USERPTR | VB2_READ;
+	queue->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC |
+				 V4L2_BUF_FLAG_TSTAMP_SRC_EOF;
+	queue->drv_priv = data;
+	queue->buf_struct_size = sizeof(struct video_i2c_buffer);
+	queue->min_buffers_needed = 1;
+	queue->ops = &video_i2c_video_qops;
+	queue->mem_ops = &vb2_vmalloc_memops;
+
+	ret = vb2_queue_init(queue);
+	if (ret < 0)
+		goto error_free_device;
+
+	data->vdev.queue = queue;
+	data->vdev.queue->lock = &data->queue_lock;
+
+	strlcpy(data->vdev.name, "I2C Transport Video", sizeof(data->vdev.name));
+
+	data->vdev.v4l2_dev = v4l2_dev;
+	data->vdev.fops = &video_i2c_fops;
+	data->vdev.lock = &data->lock;
+	data->vdev.ioctl_ops = &video_i2c_ioctl_ops;
+	data->vdev.release = video_i2c_release;
+	data->vdev.device_caps = V4L2_CAP_VIDEO_CAPTURE |
+				 V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
+
+	spin_lock_init(&data->slock);
+	INIT_LIST_HEAD(&data->vid_cap_active);
+
+	video_set_drvdata(&data->vdev, data);
+	i2c_set_clientdata(client, data);
+
+	ret = video_register_device(&data->vdev, VFL_TYPE_GRABBER, -1);
+	if (ret < 0)
+		goto error_unregister_device;
+
+	return 0;
+
+error_unregister_device:
+	v4l2_device_unregister(v4l2_dev);
+
+error_free_device:
+	kfree(data);
+
+	return ret;
+}
+
+static int video_i2c_remove(struct i2c_client *client)
+{
+	struct video_i2c_data *data = i2c_get_clientdata(client);
+
+	v4l2_device_unregister(&data->v4l2_dev);
+	video_unregister_device(&data->vdev);
+
+	return 0;
+}
+
+static const struct i2c_device_id video_i2c_id_table[] = {
+	{ "amg88xx", 0 },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, video_i2c_id_table);
+
+static struct i2c_driver video_i2c_driver = {
+	.driver = {
+		.name	= VIDEO_I2C_DRIVER,
+	},
+	.probe		= video_i2c_probe,
+	.remove		= video_i2c_remove,
+	.id_table	= video_i2c_id_table,
+};
+
+module_i2c_driver(video_i2c_driver);
+
+MODULE_AUTHOR("Matt Ranostay <mranostay@ranostay.consulting>");
+MODULE_DESCRIPTION("I2C transport video support");
+MODULE_LICENSE("GPL");
-- 
2.7.4