(whoops, apologies for the CHROMIUM tag in the subject line...)
On Tue, Jun 28, 2016 at 4:52 PM, Archit Taneja architt@codeaurora.org wrote:
On 06/27/2016 01:18 PM, Nicolas Boichat wrote:
This driver supports single input, 2 output display mux (e.g. HDMI mux), that provides its status via a GPIO.
This might not work if we had a 2 or more bridges connected one after the other at the output ports. It would be nicer if the interrupt handler directly modified the drm_bridge's next pointer rather than managing things by its own.
I don't think we can directly change ->next as different functions need different handling. For example, pre_enable should be called on all possible downstream bridges, as we cannot know in advance which bridge should be ready. So does attach, but I think that's easier to solve.
That being said, the bridge chains (by setting the next pointers) aren't expected to change after they are set up. In order to use make this a truly generic driver, we'd probably need to add some sort of locking for the entire bridge chain to make sure we don't change things in the middle of a modeset. We don't really need to add this functionality unless there are many more platforms like these have non-static muxes in the display chain.
Agree with that. Also, since our downstream bridges (HDMI connector, so no bridge, and anx7688) don't have enable/disable callbacks, we are actually using a simpler version of this driver that just leaves all downstream bridges enabled.
It would be better if this driver was considered to be used only for the mux hardware that's used on the board.
Archit
Signed-off-by: Nicolas Boichat drinkcat@chromium.org
drivers/gpu/drm/bridge/Kconfig | 11 + drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/generic-gpio-mux.c | 347 ++++++++++++++++++++++++++++++ 3 files changed, 359 insertions(+) create mode 100644 drivers/gpu/drm/bridge/generic-gpio-mux.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index da489f0..f1f6fc6 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -41,6 +41,17 @@ config DRM_DW_HDMI_AHB_AUDIO Designware HDMI block. This is used in conjunction with the i.MX6 HDMI driver.
+config DRM_GENERIC_GPIO_MUX
tristate "Generic GPIO-controlled mux"depends on DRMdepends on OFselect DRM_KMS_HELPER---help---This bridge driver models a GPIO-controlled display mux with oneinput, 2 outputs (e.g. an HDMI mux). The hardware decides whichoutput
is active, reports it as a GPIO, and the driver redirects callsto the
appropriate downstream bridge (if any).- config DRM_NXP_PTN3460 tristate "NXP PTN3460 DP/LVDS bridge" depends on OF
diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index 4846465..cb97274fd 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_DRM_ANALOGIX_ANX7688) += analogix-anx7688.o obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o +obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o obj-$(CONFIG_DRM_PARADE_PS8622) += parade-ps8622.o obj-$(CONFIG_DRM_SII902X) += sii902x.o diff --git a/drivers/gpu/drm/bridge/generic-gpio-mux.c b/drivers/gpu/drm/bridge/generic-gpio-mux.c new file mode 100644 index 0000000..d3367e2 --- /dev/null +++ b/drivers/gpu/drm/bridge/generic-gpio-mux.c @@ -0,0 +1,347 @@ +/*
- ANX7688 HDMI->DP bridge driver
- Copyright (C) 2016 Google, Inc.
- This software is licensed under the terms of the GNU General Public
- License version 2, as published by the Free Software Foundation, and
- may be copied, distributed, and modified under those terms.
- 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.
- */
+#include <linux/gpio.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_gpio.h> +#include <linux/of_graph.h> +#include <drm/drm_crtc.h> +#include <drm/drm_crtc_helper.h>
+struct gpio_display_mux {
struct device *dev;struct gpio_desc *gpiod_detect;int detect_irq;struct drm_bridge bridge;struct drm_bridge *next[2];struct mutex lock;int active;bool enabled;+};
+static inline struct gpio_display_mux *bridge_to_gpio_display_mux(
struct drm_bridge *bridge)+{
return container_of(bridge, struct gpio_display_mux, bridge);+}
+static irqreturn_t gpio_display_mux_det_threaded_handler(int unused, void *data) +{
struct gpio_display_mux *gpio_display_mux = data;struct drm_bridge *next;int active;active = gpiod_get_value(gpio_display_mux->gpiod_detect);dev_dbg(gpio_display_mux->dev, "Interrupt %d!\n", active);if (active == gpio_display_mux->active)return IRQ_HANDLED;/* Disable previous bridge */mutex_lock(&gpio_display_mux->lock);if (gpio_display_mux->enabled) {next = gpio_display_mux->next[gpio_display_mux->active];if (next && next->funcs->disable)next->funcs->disable(next);}mutex_unlock(&gpio_display_mux->lock);if (gpio_display_mux->bridge.dev)drm_kms_helper_hotplug_event(gpio_display_mux->bridge.dev);
/* Enable current bridge */mutex_lock(&gpio_display_mux->lock);if (gpio_display_mux->enabled) {next = gpio_display_mux->next[active];if (next && next->funcs->enable)next->funcs->enable(next);}gpio_display_mux->active = active;mutex_unlock(&gpio_display_mux->lock);return IRQ_HANDLED;+}
+static int gpio_display_mux_attach(struct drm_bridge *bridge) +{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;int i;for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {next = gpio_display_mux->next[i];if (next)next->encoder = bridge->encoder;}return 0;+}
+static bool gpio_display_mux_mode_fixup(struct drm_bridge *bridge,
const struct drm_display_mode *mode,struct drm_display_mode *adjusted_mode)+{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;next = gpio_display_mux->next[gpio_display_mux->active];if (next && next->funcs->mode_fixup)return next->funcs->mode_fixup(next, mode, adjusted_mode);elsereturn true;+}
+static void gpio_display_mux_mode_set(struct drm_bridge *bridge,
struct drm_display_mode *mode,struct drm_display_mode *adjusted_mode)+{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;next = gpio_display_mux->next[gpio_display_mux->active];if (next && next->funcs->mode_set)next->funcs->mode_set(next, mode, adjusted_mode);+}
+static void gpio_display_mux_enable(struct drm_bridge *bridge) +{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;mutex_lock(&gpio_display_mux->lock);next = gpio_display_mux->next[gpio_display_mux->active];if (next && next->funcs->enable)next->funcs->enable(next);gpio_display_mux->enabled = true;mutex_unlock(&gpio_display_mux->lock);+}
+static void gpio_display_mux_disable(struct drm_bridge *bridge) +{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;mutex_lock(&gpio_display_mux->lock);next = gpio_display_mux->next[gpio_display_mux->active];if (next && next->funcs->disable)next->funcs->disable(next);gpio_display_mux->enabled = false;mutex_unlock(&gpio_display_mux->lock);+}
+/**
- Since this driver _reacts_ to mux changes, we need to make sure all
- downstream bridges are pre-enabled.
- */
+static void gpio_display_mux_pre_enable(struct drm_bridge *bridge) +{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;int i;for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {next = gpio_display_mux->next[i];if (next && next->funcs->pre_enable)next->funcs->pre_enable(next);}+}
+static void gpio_display_mux_post_disable(struct drm_bridge *bridge) +{
struct gpio_display_mux *gpio_display_mux =bridge_to_gpio_display_mux(bridge);struct drm_bridge *next;int i;for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) {next = gpio_display_mux->next[i];if (next && next->funcs->post_disable)next->funcs->post_disable(next);}+}
+static const struct drm_bridge_funcs gpio_display_mux_bridge_funcs = {
.attach = gpio_display_mux_attach,.mode_fixup = gpio_display_mux_mode_fixup,.disable = gpio_display_mux_disable,.post_disable = gpio_display_mux_post_disable,.mode_set = gpio_display_mux_mode_set,.pre_enable = gpio_display_mux_pre_enable,.enable = gpio_display_mux_enable,+};
+static int gpio_display_mux_probe(struct platform_device *pdev) +{
struct device *dev = &pdev->dev;struct gpio_display_mux *gpio_display_mux;struct device_node *port, *ep, *remote;int ret;u32 reg;gpio_display_mux = devm_kzalloc(dev, sizeof(*gpio_display_mux),GFP_KERNEL);if (!gpio_display_mux)return -ENOMEM;mutex_init(&gpio_display_mux->lock);platform_set_drvdata(pdev, gpio_display_mux);gpio_display_mux->dev = &pdev->dev;gpio_display_mux->bridge.of_node = dev->of_node;gpio_display_mux->gpiod_detect =devm_gpiod_get(dev, "detect", GPIOD_IN);if (IS_ERR(gpio_display_mux->gpiod_detect))return PTR_ERR(gpio_display_mux->gpiod_detect);gpio_display_mux->detect_irq =gpiod_to_irq(gpio_display_mux->gpiod_detect);if (gpio_display_mux->detect_irq < 0) {dev_err(dev, "Failed to get output irq %d\n",gpio_display_mux->detect_irq);return -ENODEV;}port = of_graph_get_port_by_id(dev->of_node, 1);if (!port) {dev_err(dev, "Missing output port node\n");return -EINVAL;}for_each_child_of_node(port, ep) {if (!ep->name || (of_node_cmp(ep->name, "endpoint") != 0)){
of_node_put(ep);continue;}if (of_property_read_u32(ep, "reg", ®) < 0 ||reg >= ARRAY_SIZE(gpio_display_mux->next)){
dev_err(dev,"Missing/invalid reg property for endpoint%s\n",
ep->full_name);of_node_put(ep);of_node_put(port);return -EINVAL;}remote = of_graph_get_remote_port_parent(ep);if (!remote) {dev_err(dev,"Missing connector/bridge node for endpoint%s\n",
ep->full_name);of_node_put(ep);of_node_put(port);return -EINVAL;}of_node_put(ep);if (of_device_is_compatible(remote, "hdmi-connector")) {of_node_put(remote);continue;}gpio_display_mux->next[reg] = of_drm_find_bridge(remote);if (!gpio_display_mux->next[reg]) {dev_err(dev, "Waiting for external bridge %s\n",remote->name);of_node_put(remote);of_node_put(port);return -EPROBE_DEFER;}of_node_put(remote);}of_node_put(port);gpio_display_mux->bridge.funcs = &gpio_display_mux_bridge_funcs;ret = drm_bridge_add(&gpio_display_mux->bridge);if (ret < 0) {dev_err(dev, "Failed to add drm bridge\n");return ret;}ret = devm_request_threaded_irq(dev, gpio_display_mux->detect_irq,NULL,gpio_display_mux_det_threaded_handler,IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING|
IRQF_ONESHOT,"gpio-display-mux-det", gpio_display_mux);if (ret) {dev_err(dev, "Failed to request MUX_DET threaded irq\n");goto err_bridge_remove;}gpio_display_mux->active =gpiod_get_value(gpio_display_mux->gpiod_detect);return 0;+err_bridge_remove:
drm_bridge_remove(&gpio_display_mux->bridge);return ret;+}
+static int gpio_display_mux_remove(struct platform_device *pdev) +{
struct gpio_display_mux *gpio_display_mux =platform_get_drvdata(pdev);
drm_bridge_remove(&gpio_display_mux->bridge);return 0;+}
+static const struct of_device_id gpio_display_mux_match[] = {
{ .compatible = "gpio-display-mux", },{},+};
+struct platform_driver gpio_display_mux_driver = {
.probe = gpio_display_mux_probe,.remove = gpio_display_mux_remove,.driver = {.name = "gpio-display-mux",.of_match_table = gpio_display_mux_match,},+};
+module_platform_driver(gpio_display_mux_driver);
+MODULE_DESCRIPTION("GPIO-controlled display mux"); +MODULE_AUTHOR("Nicolas Boichat drinkcat@chromium.org"); +MODULE_LICENSE("GPL v2");
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