[RFC v2 1/8] drm/bridge: GPIO-controlled display multiplexer driver

Ported from chromeos-3.18 kernel.

Signed-off-by: Ulrich Hecht ulrich.hecht+renesas@gmail.com --- drivers/gpu/drm/bridge/Kconfig | 11 ++ drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/generic-gpio-mux.c | 316 ++++++++++++++++++++++++++++++ 3 files changed, 328 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 adf9ae0..966f4eb 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -15,6 +15,17 @@ config DRM_PANEL_BRIDGE menu "Display Interface Bridges" depends on DRM && DRM_BRIDGE

+config DRM_GENERIC_GPIO_MUX + tristate "Generic GPIO-controlled mux" + depends on DRM + depends on OF + select DRM_KMS_HELPER + ---help--- + This bridge driver models a GPIO-controlled display mux with one + input, 2 outputs (e.g. an HDMI mux). The hardware decides which output + is active, reports it as a GPIO, and the driver redirects calls to the + appropriate downstream bridge (if any). + config DRM_ANALOGIX_ANX78XX tristate "Analogix ANX78XX bridge" select DRM_KMS_HELPER diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index defcf1e..2d5652e 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -1,4 +1,5 @@ obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o +obj-$(CONFIG_DRM_GENERIC_GPIO_MUX) += generic-gpio-mux.o obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.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..744804b --- /dev/null +++ b/drivers/gpu/drm/bridge/generic-gpio-mux.c @@ -0,0 +1,316 @@ +/* + * 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]; +}; + +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; + int active = gpiod_get_value(gpio_display_mux->gpiod_detect); + + dev_dbg(gpio_display_mux->dev, "Interrupt %d!\n", active); + + if (gpio_display_mux->bridge.dev) + drm_kms_helper_hotplug_event(gpio_display_mux->bridge.dev); + + 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); + int active; + struct drm_bridge *next; + + active = gpiod_get_value(gpio_display_mux->gpiod_detect); + next = gpio_display_mux->next[active]; + + if (next && next->funcs->mode_fixup) + return next->funcs->mode_fixup(next, mode, adjusted_mode); + else + return 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); + int active; + struct drm_bridge *next; + + active = gpiod_get_value(gpio_display_mux->gpiod_detect); + next = gpio_display_mux->next[active]; + + if (next && next->funcs->mode_set) + next->funcs->mode_set(next, mode, adjusted_mode); +} + +/** + * 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); + } +} + +/** + * In an ideal mux driver, only the currently selected bridge should be enabled. + * For the sake of simplicity, we just just enable/disable all downstream + * bridges at the same time. + */ +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; + int i; + + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) { + next = gpio_display_mux->next[i]; + if (next && next->funcs->enable) + next->funcs->enable(next); + } +} + +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; + int i; + + for (i = 0; i < ARRAY_SIZE(gpio_display_mux->next); i++) { + next = gpio_display_mux->next[i]; + if (next && next->funcs->disable) + next->funcs->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; + + 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", &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; + } + + 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");