From: Hans Verkuil hans.verkuil@cisco.com

Add support for two new low-level events: PIN_HPD_LOW and PIN_HPD_HIGH.

This is specifically meant for use with the upcoming cec-gpio driver and makes it possible to trace when the HPD pin changes. Some HDMI sinks do strange things with the HPD and this makes it easy to debug this.

Note that this also moves the initialization of a devnode mutex and list to the allocate_adapter function: if the HPD is high, then as soon as the HPD interrupt is created an interrupt occurs and cec_queue_pin_hpd_event() is called which requires that the devnode mutex and list are initialized.

Signed-off-by: Hans Verkuil hans.verkuil@cisco.com --- drivers/media/cec/cec-adap.c | 18 +++++++++++++++++- drivers/media/cec/cec-api.c | 18 ++++++++++++++---- drivers/media/cec/cec-core.c | 8 ++++---- include/media/cec-pin.h | 4 ++++ include/media/cec.h | 12 +++++++++++- include/uapi/linux/cec.h | 2 ++ 6 files changed, 52 insertions(+), 10 deletions(-)

diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c index dd769e40416f..eb904a71609a 100644 --- a/drivers/media/cec/cec-adap.c +++ b/drivers/media/cec/cec-adap.c @@ -86,7 +86,7 @@ void cec_queue_event_fh(struct cec_fh *fh, const struct cec_event *new_ev, u64 ts) { static const u8 max_events[CEC_NUM_EVENTS] = { - 1, 1, 64, 64, + 1, 1, 64, 64, 8, 8, }; struct cec_event_entry *entry; unsigned int ev_idx = new_ev->event - 1; @@ -170,6 +170,22 @@ void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high, ktime_t ts) } EXPORT_SYMBOL_GPL(cec_queue_pin_cec_event);

+/* Notify userspace that the HPD pin changed state at the given time. */ +void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts) +{ + struct cec_event ev = { + .event = is_high ? CEC_EVENT_PIN_HPD_HIGH : + CEC_EVENT_PIN_HPD_LOW, + }; + struct cec_fh *fh; + + mutex_lock(&adap->devnode.lock); + list_for_each_entry(fh, &adap->devnode.fhs, list) + cec_queue_event_fh(fh, &ev, ktime_to_ns(ts)); + mutex_unlock(&adap->devnode.lock); +} +EXPORT_SYMBOL_GPL(cec_queue_pin_hpd_event); + /* * Queue a new message for this filehandle. * diff --git a/drivers/media/cec/cec-api.c b/drivers/media/cec/cec-api.c index a079f7fe018c..465bb3ec21f6 100644 --- a/drivers/media/cec/cec-api.c +++ b/drivers/media/cec/cec-api.c @@ -529,7 +529,7 @@ static int cec_open(struct inode *inode, struct file *filp) * Initial events that are automatically sent when the cec device is * opened. */ - struct cec_event ev_state = { + struct cec_event ev = { .event = CEC_EVENT_STATE_CHANGE, .flags = CEC_EVENT_FL_INITIAL_STATE, }; @@ -569,9 +569,19 @@ static int cec_open(struct inode *inode, struct file *filp) filp->private_data = fh;

/* Queue up initial state events */ - ev_state.state_change.phys_addr = adap->phys_addr; - ev_state.state_change.log_addr_mask = adap->log_addrs.log_addr_mask; - cec_queue_event_fh(fh, &ev_state, 0); + ev.state_change.phys_addr = adap->phys_addr; + ev.state_change.log_addr_mask = adap->log_addrs.log_addr_mask; + cec_queue_event_fh(fh, &ev, 0); +#ifdef CONFIG_CEC_PIN + if (adap->pin && adap->pin->ops->read_hpd) { + err = adap->pin->ops->read_hpd(adap); + if (err >= 0) { + ev.event = err ? CEC_EVENT_PIN_HPD_HIGH : + CEC_EVENT_PIN_HPD_LOW; + cec_queue_event_fh(fh, &ev, 0); + } + } +#endif

list_add(&fh->list, &devnode->fhs); mutex_unlock(&devnode->lock); diff --git a/drivers/media/cec/cec-core.c b/drivers/media/cec/cec-core.c index 648136e552d5..e3a1fb6d6690 100644 --- a/drivers/media/cec/cec-core.c +++ b/drivers/media/cec/cec-core.c @@ -112,10 +112,6 @@ static int __must_check cec_devnode_register(struct cec_devnode *devnode, int minor; int ret;

- /* Initialization */ - INIT_LIST_HEAD(&devnode->fhs); - mutex_init(&devnode->lock); - /* Part 1: Find a free minor number */ mutex_lock(&cec_devnode_lock); minor = find_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0); @@ -242,6 +238,10 @@ struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, INIT_LIST_HEAD(&adap->wait_queue); init_waitqueue_head(&adap->kthread_waitq);

+ /* adap->devnode initialization */ + INIT_LIST_HEAD(&adap->devnode.fhs); + mutex_init(&adap->devnode.lock); + adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name); if (IS_ERR(adap->kthread)) { pr_err("cec-%s: kernel_thread() failed\n", name); diff --git a/include/media/cec-pin.h b/include/media/cec-pin.h index f09cc9579d53..ea84b9c9e0c3 100644 --- a/include/media/cec-pin.h +++ b/include/media/cec-pin.h @@ -97,6 +97,9 @@ enum cec_pin_state { * @free: optional. Free any allocated resources. Called when the * adapter is deleted. * @status: optional, log status information. + * @read_hpd: read the HPD pin. Return true if high, false if low or + * an error if negative. If NULL or -ENOTTY is returned, + * then this is not supported. * * These operations are used by the cec pin framework to manipulate * the CEC pin. @@ -109,6 +112,7 @@ struct cec_pin_ops { void (*disable_irq)(struct cec_adapter *adap); void (*free)(struct cec_adapter *adap); void (*status)(struct cec_adapter *adap, struct seq_file *file); + int (*read_hpd)(struct cec_adapter *adap); };

#define CEC_NUM_PIN_EVENTS 128 diff --git a/include/media/cec.h b/include/media/cec.h index df6b3bd31284..9d0f983faea9 100644 --- a/include/media/cec.h +++ b/include/media/cec.h @@ -91,7 +91,7 @@ struct cec_event_entry { };

#define CEC_NUM_CORE_EVENTS 2 -#define CEC_NUM_EVENTS CEC_EVENT_PIN_CEC_HIGH +#define CEC_NUM_EVENTS CEC_EVENT_PIN_HPD_HIGH

struct cec_fh { struct list_head list; @@ -296,6 +296,16 @@ static inline void cec_received_msg(struct cec_adapter *adap, void cec_queue_pin_cec_event(struct cec_adapter *adap, bool is_high, ktime_t ts);

+/** + * cec_queue_pin_hpd_event() - queue a pin event with a given timestamp. + * + * @adap: pointer to the cec adapter + * @is_high: when true the HPD pin is high, otherwise it is low + * @ts: the timestamp for this event + * + */ +void cec_queue_pin_hpd_event(struct cec_adapter *adap, bool is_high, ktime_t ts); + /** * cec_get_edid_phys_addr() - find and return the physical address * diff --git a/include/uapi/linux/cec.h b/include/uapi/linux/cec.h index 4351c3481aea..b9f8df3a0477 100644 --- a/include/uapi/linux/cec.h +++ b/include/uapi/linux/cec.h @@ -410,6 +410,8 @@ struct cec_log_addrs { #define CEC_EVENT_LOST_MSGS 2 #define CEC_EVENT_PIN_CEC_LOW 3 #define CEC_EVENT_PIN_CEC_HIGH 4 +#define CEC_EVENT_PIN_HPD_LOW 5 +#define CEC_EVENT_PIN_HPD_HIGH 6

#define CEC_EVENT_FL_INITIAL_STATE (1 << 0) #define CEC_EVENT_FL_DROPPED_EVENTS (1 << 1)

From: Hans Verkuil hans.verkuil@cisco.com

Document the bindings for the cec-gpio module for hardware where the CEC line and optionally the HPD line are connected to GPIO lines.

Signed-off-by: Hans Verkuil hans.verkuil@cisco.com Reviewed-by: Linus Walleij linus.walleij@linaro.org --- .../devicetree/bindings/media/cec-gpio.txt | 32 ++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Documentation/devicetree/bindings/media/cec-gpio.txt

diff --git a/Documentation/devicetree/bindings/media/cec-gpio.txt b/Documentation/devicetree/bindings/media/cec-gpio.txt new file mode 100644 index 000000000000..46a0bac8b3b9 --- /dev/null +++ b/Documentation/devicetree/bindings/media/cec-gpio.txt @@ -0,0 +1,32 @@ +* HDMI CEC GPIO driver + +The HDMI CEC GPIO module supports CEC implementations where the CEC line +is hooked up to a pull-up GPIO line and - optionally - the HPD line is +hooked up to another GPIO line. + +Required properties: + - compatible: value must be "cec-gpio". + - cec-gpios: gpio that the CEC line is connected to. The line should be + tagged as open drain. + +If the CEC line is associated with an HDMI receiver/transmitter, then the +following property is also required: + + - hdmi-phandle - phandle to the HDMI controller, see also cec.txt. + +If the CEC line is not associated with an HDMI receiver/transmitter, then +the following property is optional: + + - hpd-gpios: gpio that the HPD line is connected to. + +Example for the Raspberry Pi 3 where the CEC line is connected to +pin 26 aka BCM7 aka CE1 on the GPIO pin header and the HPD line is +connected to pin 11 aka BCM17: + +#include <dt-bindings/gpio/gpio.h> + +cec-gpio { + compatible = "cec-gpio"; + cec-gpios = <&gpio 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>; + hpd-gpios = <&gpio 17 GPIO_ACTIVE_HIGH>; +};

From: Hans Verkuil hans.verkuil@cisco.com

Add a simple HDMI CEC GPIO driver that sits on top of the cec-pin framework.

While I have heard of SoCs that use the GPIO pin for CEC (apparently an early RockChip SoC used that), the main use-case of this driver is to function as a debugging tool.

By connecting the CEC line to a GPIO pin on a Raspberry Pi 3 for example it turns it into a CEC debugger and protocol analyzer.

With 'cec-ctl --monitor-pin' the CEC traffic can be analyzed.

But of course it can also be used with any hardware project where the HDMI CEC line is hooked up to a pull-up gpio line.

In addition this has (optional) support for tracing HPD changes if the HPD is connected to a GPIO.

Signed-off-by: Hans Verkuil hans.verkuil@cisco.com Reviewed-by: Linus Walleij linus.walleij@linaro.org --- drivers/media/platform/Kconfig | 10 ++ drivers/media/platform/Makefile | 2 + drivers/media/platform/cec-gpio/Makefile | 1 + drivers/media/platform/cec-gpio/cec-gpio.c | 236 +++++++++++++++++++++++++++++ 4 files changed, 249 insertions(+) create mode 100644 drivers/media/platform/cec-gpio/Makefile create mode 100644 drivers/media/platform/cec-gpio/cec-gpio.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig index 7e7cc49b8674..e4c89a16a3e7 100644 --- a/drivers/media/platform/Kconfig +++ b/drivers/media/platform/Kconfig @@ -553,6 +553,16 @@ config VIDEO_MESON_AO_CEC This is a driver for Amlogic Meson SoCs AO CEC interface. It uses the generic CEC framework interface. CEC bus is present in the HDMI connector and enables communication + +config CEC_GPIO + tristate "Generic GPIO-based CEC driver" + depends on PREEMPT + select CEC_CORE + select CEC_PIN + select GPIOLIB + ---help--- + This is a generic GPIO-based CEC driver. + The CEC bus is present in the HDMI connector and enables communication between compatible devices.

config VIDEO_SAMSUNG_S5P_CEC diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile index c1ef946bf032..9bf48f118537 100644 --- a/drivers/media/platform/Makefile +++ b/drivers/media/platform/Makefile @@ -26,6 +26,8 @@ obj-$(CONFIG_VIDEO_CODA) += coda/

obj-$(CONFIG_VIDEO_SH_VEU) += sh_veu.o

+obj-$(CONFIG_CEC_GPIO) += cec-gpio/ + obj-$(CONFIG_VIDEO_MEM2MEM_DEINTERLACE) += m2m-deinterlace.o

obj-$(CONFIG_VIDEO_MUX) += video-mux.o diff --git a/drivers/media/platform/cec-gpio/Makefile b/drivers/media/platform/cec-gpio/Makefile new file mode 100644 index 000000000000..e82b258afa55 --- /dev/null +++ b/drivers/media/platform/cec-gpio/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_CEC_GPIO) += cec-gpio.o diff --git a/drivers/media/platform/cec-gpio/cec-gpio.c b/drivers/media/platform/cec-gpio/cec-gpio.c new file mode 100644 index 000000000000..eb982bce99fc --- /dev/null +++ b/drivers/media/platform/cec-gpio/cec-gpio.c @@ -0,0 +1,236 @@ +/* + * Copyright 2017 Cisco Systems, Inc. and/or its affiliates. All rights reserved. + * + * This program is free software; you may redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * 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. + */ + +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/gpio/consumer.h> +#include <media/cec-pin.h> + +struct cec_gpio { + struct cec_adapter *adap; + struct device *dev; + + struct gpio_desc *cec_gpio; + int cec_irq; + bool cec_is_low; + bool cec_have_irq; + + struct gpio_desc *hpd_gpio; + int hpd_irq; + bool hpd_is_high; + ktime_t hpd_ts; +}; + +static bool cec_gpio_read(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (cec->cec_is_low) + return false; + return gpiod_get_value(cec->cec_gpio); +} + +static void cec_gpio_high(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (!cec->cec_is_low) + return; + cec->cec_is_low = false; + gpiod_set_value(cec->cec_gpio, 1); +} + +static void cec_gpio_low(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (cec->cec_is_low) + return; + if (WARN_ON_ONCE(cec->cec_have_irq)) + free_irq(cec->cec_irq, cec); + cec->cec_have_irq = false; + cec->cec_is_low = true; + gpiod_set_value(cec->cec_gpio, 0); +} + +static irqreturn_t cec_hpd_gpio_irq_handler_thread(int irq, void *priv) +{ + struct cec_gpio *cec = priv; + + cec_queue_pin_hpd_event(cec->adap, cec->hpd_is_high, cec->hpd_ts); + return IRQ_HANDLED; +} + +static irqreturn_t cec_hpd_gpio_irq_handler(int irq, void *priv) +{ + struct cec_gpio *cec = priv; + + cec->hpd_ts = ktime_get(); + cec->hpd_is_high = gpiod_get_value(cec->hpd_gpio); + return IRQ_WAKE_THREAD; +} + +static irqreturn_t cec_gpio_irq_handler(int irq, void *priv) +{ + struct cec_gpio *cec = priv; + + cec_pin_changed(cec->adap, gpiod_get_value(cec->cec_gpio)); + return IRQ_HANDLED; +} + +static bool cec_gpio_enable_irq(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (cec->cec_have_irq) + return true; + + if (request_irq(cec->cec_irq, cec_gpio_irq_handler, + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, + adap->name, cec)) + return false; + cec->cec_have_irq = true; + return true; +} + +static void cec_gpio_disable_irq(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (cec->cec_have_irq) + free_irq(cec->cec_irq, cec); + cec->cec_have_irq = false; +} + +static void cec_gpio_status(struct cec_adapter *adap, struct seq_file *file) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + seq_printf(file, "mode: %s\n", cec->cec_is_low ? "low-drive" : "read"); + if (cec->cec_have_irq) + seq_printf(file, "using irq: %d\n", cec->cec_irq); + if (cec->hpd_gpio) + seq_printf(file, "hpd: %s\n", + cec->hpd_is_high ? "high" : "low"); +} + +static int cec_gpio_read_hpd(struct cec_adapter *adap) +{ + struct cec_gpio *cec = cec_get_drvdata(adap); + + if (!cec->hpd_gpio) + return -ENOTTY; + return gpiod_get_value(cec->hpd_gpio); +} + +static void cec_gpio_free(struct cec_adapter *adap) +{ + cec_gpio_disable_irq(adap); +} + +static const struct cec_pin_ops cec_gpio_pin_ops = { + .read = cec_gpio_read, + .low = cec_gpio_low, + .high = cec_gpio_high, + .enable_irq = cec_gpio_enable_irq, + .disable_irq = cec_gpio_disable_irq, + .status = cec_gpio_status, + .free = cec_gpio_free, + .read_hpd = cec_gpio_read_hpd, +}; + +static int cec_gpio_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct cec_gpio *cec; + int ret; + + cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL); + if (!cec) + return -ENOMEM; + + cec->dev = dev; + + cec->cec_gpio = devm_gpiod_get(dev, "cec", GPIOD_IN); + if (IS_ERR(cec->cec_gpio)) + return PTR_ERR(cec->cec_gpio); + cec->cec_irq = gpiod_to_irq(cec->cec_gpio); + + cec->hpd_gpio = devm_gpiod_get_optional(dev, "hpd", GPIOD_IN); + if (IS_ERR(cec->hpd_gpio)) + return PTR_ERR(cec->hpd_gpio); + + cec->adap = cec_pin_allocate_adapter(&cec_gpio_pin_ops, + cec, pdev->name, CEC_CAP_DEFAULTS | CEC_CAP_PHYS_ADDR | + CEC_CAP_MONITOR_ALL | CEC_CAP_MONITOR_PIN); + if (IS_ERR(cec->adap)) + return PTR_ERR(cec->adap); + + if (cec->hpd_gpio) { + cec->hpd_irq = gpiod_to_irq(cec->hpd_gpio); + ret = devm_request_threaded_irq(dev, cec->hpd_irq, + cec_hpd_gpio_irq_handler, + cec_hpd_gpio_irq_handler_thread, + IRQF_ONESHOT | + IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING, + "hpd-gpio", cec); + if (ret) + return ret; + } + + ret = cec_register_adapter(cec->adap, &pdev->dev); + if (ret) { + cec_delete_adapter(cec->adap); + return ret; + } + + platform_set_drvdata(pdev, cec); + return 0; +} + +static int cec_gpio_remove(struct platform_device *pdev) +{ + struct cec_gpio *cec = platform_get_drvdata(pdev); + + cec_unregister_adapter(cec->adap); + return 0; +} + +static const struct of_device_id cec_gpio_match[] = { + { + .compatible = "cec-gpio", + }, + {}, +}; +MODULE_DEVICE_TABLE(of, cec_gpio_match); + +static struct platform_driver cec_gpio_pdrv = { + .probe = cec_gpio_probe, + .remove = cec_gpio_remove, + .driver = { + .name = "cec-gpio", + .of_match_table = cec_gpio_match, + }, +}; + +module_platform_driver(cec_gpio_pdrv); + +MODULE_AUTHOR("Hans Verkuil hans.verkuil@cisco.com"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("CEC GPIO driver");