Add transparent LVDS decoder driver.
A transparent LVDS decoder is a DRM bridge device that does not require any configuration and converts LVDS input to digital CMOS/TTL parallel data output. The driver is compatible with Thine THC63LVD1024 device that can control a few power supplies and a few enable GPIOs.
Signed-off-by: Jacopo Mondi jacopo+renesas@jmondi.org --- drivers/gpu/drm/bridge/Kconfig | 8 ++ drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/lvds-decoder.c | 239 ++++++++++++++++++++++++++++++++++ 3 files changed, 248 insertions(+) create mode 100644 drivers/gpu/drm/bridge/lvds-decoder.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index 3b99d5a..e52a5af 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -32,6 +32,14 @@ config DRM_DUMB_VGA_DAC help Support for RGB to VGA DAC based bridges
+config DRM_LVDS_DECODER + tristate "Transparent LVDS to parallel decoder support" + depends on OF + select DRM_PANEL_BRIDGE + help + Support for transparent LVDS to parallel decoders that don't require + any configuration. + config DRM_LVDS_ENCODER tristate "Transparent parallel to LVDS encoder support" depends on OF diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index 373eb28..edc2332 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 obj-$(CONFIG_DRM_ANALOGIX_ANX78XX) += analogix-anx78xx.o obj-$(CONFIG_DRM_DUMB_VGA_DAC) += dumb-vga-dac.o +obj-$(CONFIG_DRM_LVDS_DECODER) += lvds-decoder.o obj-$(CONFIG_DRM_LVDS_ENCODER) += lvds-encoder.o obj-$(CONFIG_DRM_MEGACHIPS_STDPXXXX_GE_B850V3_FW) += megachips-stdpxxxx-ge-b850v3-fw.o obj-$(CONFIG_DRM_NXP_PTN3460) += nxp-ptn3460.o diff --git a/drivers/gpu/drm/bridge/lvds-decoder.c b/drivers/gpu/drm/bridge/lvds-decoder.c new file mode 100644 index 0000000..3aada7e --- /dev/null +++ b/drivers/gpu/drm/bridge/lvds-decoder.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * LVDS to parallel data DRM bridge driver. + * + * Copyright (C) 2018 Jacopo Mondi jacopo+renesas@jmondi.org + */ + +#include <drm/drmP.h> +#include <drm/drm_bridge.h> +#include <drm/drm_panel.h> + +#include <linux/gpio/consumer.h> +#include <linux/of_graph.h> +#include <linux/regulator/consumer.h> + +struct lvds_decoder { + struct device *dev; + + struct regulator *vccs[4]; + + struct gpio_desc *pwdn; + struct gpio_desc *oe; + + struct drm_bridge bridge; + struct drm_bridge *next; + struct drm_encoder *bridge_encoder; +}; + +static inline struct lvds_decoder *to_lvds_decoder(struct drm_bridge *bridge) +{ + return container_of(bridge, struct lvds_decoder, bridge); +} + +static int lvds_decoder_attach(struct drm_bridge *bridge) +{ + struct lvds_decoder *lvds = to_lvds_decoder(bridge); + + return drm_bridge_attach(bridge->encoder, lvds->next, bridge); +} + +static void lvds_decoder_enable(struct drm_bridge *bridge) +{ + struct lvds_decoder *lvds = to_lvds_decoder(bridge); + struct regulator *vcc; + unsigned int i; + int ret; + + for (i = 0; i < ARRAY_SIZE(lvds->vccs); i++) { + vcc = lvds->vccs[i]; + if (vcc) { + ret = regulator_enable(vcc); + if (ret) + goto error_vcc_enable; + } + } + + if (lvds->pwdn) + gpiod_set_value(lvds->pwdn, 0); + + if (lvds->oe) + gpiod_set_value(lvds->oe, 1); + + return; + +error_vcc_enable: + dev_err(lvds->dev, "Failed to enable regulator %u\n", i); +} + +static void lvds_decoder_disable(struct drm_bridge *bridge) +{ + struct lvds_decoder *lvds = to_lvds_decoder(bridge); + struct regulator *vcc; + unsigned int i; + int ret; + + for (i = 0; i < ARRAY_SIZE(lvds->vccs); i++) { + vcc = lvds->vccs[i]; + if (vcc) { + ret = regulator_disable(vcc); + if (ret) + goto error_vcc_disable; + } + } + + if (lvds->pwdn) + gpiod_set_value(lvds->pwdn, 1); + + if (lvds->oe) + gpiod_set_value(lvds->oe, 0); + + return; + +error_vcc_disable: + dev_err(lvds->dev, "Failed to enable regulator %u\n", i); +} + +struct drm_bridge_funcs lvds_dec_bridge_func = { + .attach = lvds_decoder_attach, + .enable = lvds_decoder_enable, + .disable = lvds_decoder_disable, +}; + +static int lvds_decoder_parse_dt(struct lvds_decoder *lvds) +{ + struct device_node *lvds_output; + struct device_node *remote; + int ret = 0; + + lvds_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, -1); + if (!lvds_output) { + dev_err(lvds->dev, "Missing endpoint in Port@1\n"); + return -ENODEV; + } + + remote = of_graph_get_remote_port_parent(lvds_output); + if (!remote) { + dev_err(lvds->dev, "Endpoint in Port@1 unconnected\n"); + ret = -ENODEV; + goto error_put_lvds_node; + } + + if (!of_device_is_available(remote)) { + dev_err(lvds->dev, "Port@1 remote endpoint is disabled\n"); + ret = -ENODEV; + goto error_put_remote_node; + } + + lvds->next = of_drm_find_bridge(remote); + if (!lvds->next) + ret = -EPROBE_DEFER; + +error_put_remote_node: + of_node_put(remote); +error_put_lvds_node: + of_node_put(lvds_output); + + return ret; +} + +static int lvds_decoder_gpio_init(struct lvds_decoder *lvds) +{ + lvds->pwdn = devm_gpiod_get_optional(lvds->dev, "pwdn", GPIOD_OUT_LOW); + if (IS_ERR(lvds->pwdn)) { + dev_err(lvds->dev, "Unable to get GPIO "pwdn"\n"); + return PTR_ERR(lvds->pwdn); + } + + lvds->oe = devm_gpiod_get_optional(lvds->dev, "oe", GPIOD_OUT_LOW); + if (IS_ERR(lvds->oe)) { + dev_err(lvds->dev, "Unable to get GPIO "oe"\n"); + return PTR_ERR(lvds->oe); + } + + return 0; +} + +static int lvds_decoder_regulator_init(struct lvds_decoder *lvds) +{ + const char *reg_names[4] = { "vcc", "lvcc", "pvcc", "cvcc", }; + struct regulator **reg; + int i; + + for (i = 0, reg = &lvds->vccs[0]; + i < ARRAY_SIZE(lvds->vccs); i++, reg++) { + *reg = devm_regulator_get_optional(lvds->dev, reg_names[i]); + if (IS_ERR(*reg)) { + if (PTR_ERR(*reg) == -EPROBE_DEFER) + return -EPROBE_DEFER; + *reg = NULL; + } + } + + return 0; +} + +static int lvds_decoder_probe(struct platform_device *pdev) +{ + struct lvds_decoder *lvds; + int ret; + + lvds = devm_kzalloc(&pdev->dev, sizeof(*lvds), GFP_KERNEL); + if (!lvds) + return -ENOMEM; + + lvds->dev = &pdev->dev; + platform_set_drvdata(pdev, lvds); + + ret = lvds_decoder_regulator_init(lvds); + if (ret) + return ret; + + ret = lvds_decoder_gpio_init(lvds); + if (ret) + return ret; + + ret = lvds_decoder_parse_dt(lvds); + if (ret) + return ret; + + lvds->bridge.driver_private = lvds; + lvds->bridge.of_node = pdev->dev.of_node; + lvds->bridge.funcs = &lvds_dec_bridge_func; + + drm_bridge_add(&lvds->bridge); + + return 0; +} + +static int lvds_decoder_remove(struct platform_device *pdev) +{ + struct lvds_decoder *lvds = platform_get_drvdata(pdev); + + drm_bridge_remove(&lvds->bridge); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id lvds_decoder_match[] = { + { .compatible = "thine,thc63lvd1024", }, + { .compatible = "lvds-decoder", }, + { }, +}; +MODULE_DEVICE_TABLE(of, lvds_decoder_match); +#endif + +static struct platform_driver lvds_decoder_driver = { + .probe = lvds_decoder_probe, + .remove = lvds_decoder_remove, + .driver = { + .name = "lvds_decoder", + .of_match_table = lvds_decoder_match, + }, +}; +module_platform_driver(lvds_decoder_driver); + +MODULE_AUTHOR("Jacopo Mondi jacopo@jmondi.org"); +MODULE_DESCRIPTION("Transparent LVDS to parallel data decoder"); +MODULE_LICENSE("GPL v2");