summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--drivers/gpu/drm/Kconfig8
-rw-r--r--drivers/gpu/drm/Makefile1
-rw-r--r--drivers/gpu/drm/drm_dp_aux_dev.c368
-rw-r--r--drivers/gpu/drm/drm_dp_helper.c16
-rw-r--r--drivers/gpu/drm/drm_kms_helper_common.c15
-rw-r--r--include/drm/drm_dp_aux_dev.h62
6 files changed, 468 insertions, 2 deletions
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 8ae7ab68cb97..7b1560792e6a 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -25,6 +25,14 @@ config DRM_MIPI_DSI
bool
depends on DRM
+config DRM_DP_AUX_CHARDEV
+ bool "DRM DP AUX Interface"
+ depends on DRM
+ help
+ Choose this option to enable a /dev/drm_dp_auxN node that allows to
+ read and write values to arbitrary DPCD registers on the DP aux
+ channel.
+
config DRM_KMS_HELPER
tristate
depends on DRM
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index f619ff4b22a2..e07fd93981e1 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -28,6 +28,7 @@ drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
+drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c
new file mode 100644
index 000000000000..f73b38b33a8e
--- /dev/null
+++ b/drivers/gpu/drm/drm_dp_aux_dev.c
@@ -0,0 +1,368 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Rafael Antognolli <rafael.antognolli@intel.com>
+ *
+ */
+
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <drm/drm_dp_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drmP.h>
+
+struct drm_dp_aux_dev {
+ unsigned index;
+ struct drm_dp_aux *aux;
+ struct device *dev;
+ struct kref refcount;
+ atomic_t usecount;
+};
+
+#define DRM_AUX_MINORS 256
+#define AUX_MAX_OFFSET (1 << 20)
+static DEFINE_IDR(aux_idr);
+static DEFINE_MUTEX(aux_idr_mutex);
+static struct class *drm_dp_aux_dev_class;
+static int drm_dev_major = -1;
+
+static struct drm_dp_aux_dev *drm_dp_aux_dev_get_by_minor(unsigned index)
+{
+ struct drm_dp_aux_dev *aux_dev = NULL;
+
+ mutex_lock(&aux_idr_mutex);
+ aux_dev = idr_find(&aux_idr, index);
+ if (!kref_get_unless_zero(&aux_dev->refcount))
+ aux_dev = NULL;
+ mutex_unlock(&aux_idr_mutex);
+
+ return aux_dev;
+}
+
+static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct drm_dp_aux *aux)
+{
+ struct drm_dp_aux_dev *aux_dev;
+ int index;
+
+ aux_dev = kzalloc(sizeof(*aux_dev), GFP_KERNEL);
+ if (!aux_dev)
+ return ERR_PTR(-ENOMEM);
+ aux_dev->aux = aux;
+ atomic_set(&aux_dev->usecount, 1);
+ kref_init(&aux_dev->refcount);
+
+ mutex_lock(&aux_idr_mutex);
+ index = idr_alloc_cyclic(&aux_idr, aux_dev, 0, DRM_AUX_MINORS,
+ GFP_KERNEL);
+ mutex_unlock(&aux_idr_mutex);
+ if (index < 0) {
+ kfree(aux_dev);
+ return ERR_PTR(index);
+ }
+ aux_dev->index = index;
+
+ return aux_dev;
+}
+
+static void release_drm_dp_aux_dev(struct kref *ref)
+{
+ struct drm_dp_aux_dev *aux_dev =
+ container_of(ref, struct drm_dp_aux_dev, refcount);
+
+ kfree(aux_dev);
+}
+
+static ssize_t name_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ ssize_t res;
+ struct drm_dp_aux_dev *aux_dev =
+ drm_dp_aux_dev_get_by_minor(MINOR(dev->devt));
+
+ if (!aux_dev)
+ return -ENODEV;
+
+ res = sprintf(buf, "%s\n", aux_dev->aux->name);
+ kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
+
+ return res;
+}
+static DEVICE_ATTR_RO(name);
+
+static struct attribute *drm_dp_aux_attrs[] = {
+ &dev_attr_name.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(drm_dp_aux);
+
+static int auxdev_open(struct inode *inode, struct file *file)
+{
+ unsigned int minor = iminor(inode);
+ struct drm_dp_aux_dev *aux_dev;
+
+ aux_dev = drm_dp_aux_dev_get_by_minor(minor);
+ if (!aux_dev)
+ return -ENODEV;
+
+ file->private_data = aux_dev;
+ return 0;
+}
+
+static loff_t auxdev_llseek(struct file *file, loff_t offset, int whence)
+{
+ return fixed_size_llseek(file, offset, whence, AUX_MAX_OFFSET);
+}
+
+static ssize_t auxdev_read(struct file *file, char __user *buf, size_t count,
+ loff_t *offset)
+{
+ size_t bytes_pending, num_bytes_processed = 0;
+ struct drm_dp_aux_dev *aux_dev = file->private_data;
+ ssize_t res = 0;
+
+ if (!atomic_inc_not_zero(&aux_dev->usecount))
+ return -ENODEV;
+
+ bytes_pending = min((loff_t)count, AUX_MAX_OFFSET - (*offset));
+
+ if (!access_ok(VERIFY_WRITE, buf, bytes_pending)) {
+ res = -EFAULT;
+ goto out;
+ }
+
+ while (bytes_pending > 0) {
+ uint8_t localbuf[DP_AUX_MAX_PAYLOAD_BYTES];
+ ssize_t todo = min_t(size_t, bytes_pending, sizeof(localbuf));
+
+ res = drm_dp_dpcd_read(aux_dev->aux, *offset, localbuf, todo);
+ if (res <= 0) {
+ res = num_bytes_processed ? num_bytes_processed : res;
+ goto out;
+ }
+ if (__copy_to_user(buf + num_bytes_processed, localbuf, res)) {
+ res = num_bytes_processed ?
+ num_bytes_processed : -EFAULT;
+ goto out;
+ }
+ bytes_pending -= res;
+ *offset += res;
+ num_bytes_processed += res;
+ res = num_bytes_processed;
+ }
+
+out:
+ atomic_dec(&aux_dev->usecount);
+ wake_up_atomic_t(&aux_dev->usecount);
+ return res;
+}
+
+static ssize_t auxdev_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *offset)
+{
+ size_t bytes_pending, num_bytes_processed = 0;
+ struct drm_dp_aux_dev *aux_dev = file->private_data;
+ ssize_t res = 0;
+
+ if (!atomic_inc_not_zero(&aux_dev->usecount))
+ return -ENODEV;
+
+ bytes_pending = min((loff_t)count, AUX_MAX_OFFSET - *offset);
+
+ if (!access_ok(VERIFY_READ, buf, bytes_pending)) {
+ res = -EFAULT;
+ goto out;
+ }
+
+ while (bytes_pending > 0) {
+ uint8_t localbuf[DP_AUX_MAX_PAYLOAD_BYTES];
+ ssize_t todo = min_t(size_t, bytes_pending, sizeof(localbuf));
+
+ if (__copy_from_user(localbuf,
+ buf + num_bytes_processed, todo)) {
+ res = num_bytes_processed ?
+ num_bytes_processed : -EFAULT;
+ goto out;
+ }
+
+ res = drm_dp_dpcd_write(aux_dev->aux, *offset, localbuf, todo);
+ if (res <= 0) {
+ res = num_bytes_processed ? num_bytes_processed : res;
+ goto out;
+ }
+ bytes_pending -= res;
+ *offset += res;
+ num_bytes_processed += res;
+ res = num_bytes_processed;
+ }
+
+out:
+ atomic_dec(&aux_dev->usecount);
+ wake_up_atomic_t(&aux_dev->usecount);
+ return res;
+}
+
+static int auxdev_release(struct inode *inode, struct file *file)
+{
+ struct drm_dp_aux_dev *aux_dev = file->private_data;
+
+ kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
+ return 0;
+}
+
+static const struct file_operations auxdev_fops = {
+ .owner = THIS_MODULE,
+ .llseek = auxdev_llseek,
+ .read = auxdev_read,
+ .write = auxdev_write,
+ .open = auxdev_open,
+ .release = auxdev_release,
+};
+
+#define to_auxdev(d) container_of(d, struct drm_dp_aux_dev, aux)
+
+static struct drm_dp_aux_dev *drm_dp_aux_dev_get_by_aux(struct drm_dp_aux *aux)
+{
+ struct drm_dp_aux_dev *iter, *aux_dev = NULL;
+ int id;
+
+ /* don't increase kref count here because this function should only be
+ * used by drm_dp_aux_unregister_devnode. Thus, it will always have at
+ * least one reference - the one that drm_dp_aux_register_devnode
+ * created
+ */
+ mutex_lock(&aux_idr_mutex);
+ idr_for_each_entry(&aux_idr, iter, id) {
+ if (iter->aux == aux) {
+ aux_dev = iter;
+ break;
+ }
+ }
+ mutex_unlock(&aux_idr_mutex);
+ return aux_dev;
+}
+
+static int auxdev_wait_atomic_t(atomic_t *p)
+{
+ schedule();
+ return 0;
+}
+/**
+ * drm_dp_aux_unregister_devnode() - unregister a devnode for this aux channel
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
+{
+ struct drm_dp_aux_dev *aux_dev;
+ unsigned int minor;
+
+ aux_dev = drm_dp_aux_dev_get_by_aux(aux);
+ if (!aux_dev) /* attach must have failed */
+ return;
+
+ mutex_lock(&aux_idr_mutex);
+ idr_remove(&aux_idr, aux_dev->index);
+ mutex_unlock(&aux_idr_mutex);
+
+ atomic_dec(&aux_dev->usecount);
+ wait_on_atomic_t(&aux_dev->usecount, auxdev_wait_atomic_t,
+ TASK_UNINTERRUPTIBLE);
+
+ minor = aux_dev->index;
+ if (aux_dev->dev)
+ device_destroy(drm_dp_aux_dev_class,
+ MKDEV(drm_dev_major, minor));
+
+ DRM_DEBUG("drm_dp_aux_dev: aux [%s] unregistering\n", aux->name);
+ kref_put(&aux_dev->refcount, release_drm_dp_aux_dev);
+}
+EXPORT_SYMBOL(drm_dp_aux_unregister_devnode);
+
+/**
+ * drm_dp_aux_register_devnode() - register a devnode for this aux channel
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+{
+ struct drm_dp_aux_dev *aux_dev;
+ int res;
+
+ aux_dev = alloc_drm_dp_aux_dev(aux);
+ if (IS_ERR(aux_dev))
+ return PTR_ERR(aux_dev);
+
+ aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
+ MKDEV(drm_dev_major, aux_dev->index), NULL,
+ "drm_dp_aux%d", aux_dev->index);
+ if (IS_ERR(aux_dev->dev)) {
+ res = PTR_ERR(aux_dev->dev);
+ aux_dev->dev = NULL;
+ goto error;
+ }
+
+ DRM_DEBUG("drm_dp_aux_dev: aux [%s] registered as minor %d\n",
+ aux->name, aux_dev->index);
+ return 0;
+error:
+ drm_dp_aux_unregister_devnode(aux);
+ return res;
+}
+EXPORT_SYMBOL(drm_dp_aux_register_devnode);
+
+int drm_dp_aux_dev_init(void)
+{
+ int res;
+
+ drm_dp_aux_dev_class = class_create(THIS_MODULE, "drm_dp_aux_dev");
+ if (IS_ERR(drm_dp_aux_dev_class)) {
+ res = PTR_ERR(drm_dp_aux_dev_class);
+ goto out;
+ }
+ drm_dp_aux_dev_class->dev_groups = drm_dp_aux_groups;
+
+ res = register_chrdev(0, "aux", &auxdev_fops);
+ if (res < 0)
+ goto out;
+ drm_dev_major = res;
+
+ return 0;
+out:
+ class_destroy(drm_dp_aux_dev_class);
+ return res;
+}
+EXPORT_SYMBOL(drm_dp_aux_dev_init);
+
+void drm_dp_aux_dev_exit(void)
+{
+ unregister_chrdev(drm_dev_major, "aux");
+ class_destroy(drm_dp_aux_dev_class);
+}
+EXPORT_SYMBOL(drm_dp_aux_dev_exit);
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 9535c5b60387..7d58f594cffe 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -28,6 +28,7 @@
#include <linux/sched.h>
#include <linux/i2c.h>
#include <drm/drm_dp_helper.h>
+#include <drm/drm_dp_aux_dev.h>
#include <drm/drmP.h>
/**
@@ -754,6 +755,8 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
*/
int drm_dp_aux_register(struct drm_dp_aux *aux)
{
+ int ret;
+
mutex_init(&aux->hw_mutex);
aux->ddc.algo = &drm_dp_i2c_algo;
@@ -768,7 +771,17 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
sizeof(aux->ddc.name));
- return i2c_add_adapter(&aux->ddc);
+ ret = drm_dp_aux_register_devnode(aux);
+ if (ret)
+ return ret;
+
+ ret = i2c_add_adapter(&aux->ddc);
+ if (ret) {
+ drm_dp_aux_unregister_devnode(aux);
+ return ret;
+ }
+
+ return 0;
}
EXPORT_SYMBOL(drm_dp_aux_register);
@@ -778,6 +791,7 @@ EXPORT_SYMBOL(drm_dp_aux_register);
*/
void drm_dp_aux_unregister(struct drm_dp_aux *aux)
{
+ drm_dp_aux_unregister_devnode(aux);
i2c_del_adapter(&aux->ddc);
}
EXPORT_SYMBOL(drm_dp_aux_unregister);
diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
index d3610058de3c..3187c4bb01cb 100644
--- a/drivers/gpu/drm/drm_kms_helper_common.c
+++ b/drivers/gpu/drm/drm_kms_helper_common.c
@@ -27,6 +27,7 @@
#include <drm/drmP.h>
#include <drm/drm_fb_helper.h>
+#include <drm/drm_dp_aux_dev.h>
MODULE_AUTHOR("David Airlie, Jesse Barnes");
MODULE_DESCRIPTION("DRM KMS helper");
@@ -34,13 +35,25 @@ MODULE_LICENSE("GPL and additional rights");
static int __init drm_kms_helper_init(void)
{
+ int ret;
+
/* Call init functions from specific kms helpers here */
- return drm_fb_helper_modinit();
+ ret = drm_fb_helper_modinit();
+ if (ret < 0)
+ goto out;
+
+ ret = drm_dp_aux_dev_init();
+ if (ret < 0)
+ goto out;
+
+out:
+ return ret;
}
static void __exit drm_kms_helper_exit(void)
{
/* Call exit functions from specific kms helpers here */
+ drm_dp_aux_dev_exit();
}
module_init(drm_kms_helper_init);
diff --git a/include/drm/drm_dp_aux_dev.h b/include/drm/drm_dp_aux_dev.h
new file mode 100644
index 000000000000..1b76d990d8ab
--- /dev/null
+++ b/include/drm/drm_dp_aux_dev.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Rafael Antognolli <rafael.antognolli@intel.com>
+ *
+ */
+
+#ifndef DRM_DP_AUX_DEV
+#define DRM_DP_AUX_DEV
+
+#include <drm/drm_dp_helper.h>
+
+#ifdef CONFIG_DRM_DP_AUX_CHARDEV
+
+int drm_dp_aux_dev_init(void);
+void drm_dp_aux_dev_exit(void);
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
+void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
+
+#else
+
+static inline int drm_dp_aux_dev_init(void)
+{
+ return 0;
+}
+
+static inline void drm_dp_aux_dev_exit(void)
+{
+}
+
+static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+{
+ return 0;
+}
+
+static inline void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
+{
+}
+
+#endif
+
+#endif