From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
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@xxxxxxxxx>
---
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@xxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("CEC GPIO driver");
--
2.14.1
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