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");