diff options
Diffstat (limited to 'drivers/gpu/drm/bridge/simple-bridge.c')
-rw-r--r-- | drivers/gpu/drm/bridge/simple-bridge.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c new file mode 100644 index 000000000000..00d810c99193 --- /dev/null +++ b/drivers/gpu/drm/bridge/simple-bridge.c @@ -0,0 +1,306 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2015-2016 Free Electrons + * Copyright (C) 2015-2016 NextThing Co + * + * Maxime Ripard <maxime.ripard@free-electrons.com> + */ + +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/of_graph.h> +#include <linux/regulator/consumer.h> + +#include <drm/drm_atomic_helper.h> +#include <drm/drm_bridge.h> +#include <drm/drm_crtc.h> +#include <drm/drm_print.h> +#include <drm/drm_probe_helper.h> + +struct simple_bridge { + struct drm_bridge bridge; + struct drm_connector connector; + + struct i2c_adapter *ddc; + struct regulator *vdd; +}; + +static inline struct simple_bridge * +drm_bridge_to_simple_bridge(struct drm_bridge *bridge) +{ + return container_of(bridge, struct simple_bridge, bridge); +} + +static inline struct simple_bridge * +drm_connector_to_simple_bridge(struct drm_connector *connector) +{ + return container_of(connector, struct simple_bridge, connector); +} + +static int simple_bridge_get_modes(struct drm_connector *connector) +{ + struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); + struct edid *edid; + int ret; + + if (!sbridge->ddc) + goto fallback; + + edid = drm_get_edid(connector, sbridge->ddc); + if (!edid) { + DRM_INFO("EDID readout failed, falling back to standard modes\n"); + goto fallback; + } + + drm_connector_update_edid_property(connector, edid); + ret = drm_add_edid_modes(connector, edid); + kfree(edid); + return ret; + +fallback: + /* + * In case we cannot retrieve the EDIDs (broken or missing i2c + * bus), fallback on the XGA standards + */ + ret = drm_add_modes_noedid(connector, 1920, 1200); + + /* And prefer a mode pretty much anyone can handle */ + drm_set_preferred_mode(connector, 1024, 768); + + return ret; +} + +static const struct drm_connector_helper_funcs simple_bridge_con_helper_funcs = { + .get_modes = simple_bridge_get_modes, +}; + +static enum drm_connector_status +simple_bridge_connector_detect(struct drm_connector *connector, bool force) +{ + struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector); + + /* + * Even if we have an I2C bus, we can't assume that the cable + * is disconnected if drm_probe_ddc fails. Some cables don't + * wire the DDC pins, or the I2C bus might not be working at + * all. + */ + if (sbridge->ddc && drm_probe_ddc(sbridge->ddc)) + return connector_status_connected; + + return connector_status_unknown; +} + +static const struct drm_connector_funcs simple_bridge_con_funcs = { + .detect = simple_bridge_connector_detect, + .fill_modes = drm_helper_probe_single_connector_modes, + .destroy = drm_connector_cleanup, + .reset = drm_atomic_helper_connector_reset, + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, +}; + +static int simple_bridge_attach(struct drm_bridge *bridge, + enum drm_bridge_attach_flags flags) +{ + struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); + int ret; + + if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) { + DRM_ERROR("Fix bridge driver to make connector optional!"); + return -EINVAL; + } + + if (!bridge->encoder) { + DRM_ERROR("Missing encoder\n"); + return -ENODEV; + } + + drm_connector_helper_add(&sbridge->connector, + &simple_bridge_con_helper_funcs); + ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector, + &simple_bridge_con_funcs, + DRM_MODE_CONNECTOR_VGA, + sbridge->ddc); + if (ret) { + DRM_ERROR("Failed to initialize connector\n"); + return ret; + } + + drm_connector_attach_encoder(&sbridge->connector, + bridge->encoder); + + return 0; +} + +static void simple_bridge_enable(struct drm_bridge *bridge) +{ + struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); + int ret = 0; + + if (sbridge->vdd) + ret = regulator_enable(sbridge->vdd); + + if (ret) + DRM_ERROR("Failed to enable vdd regulator: %d\n", ret); +} + +static void simple_bridge_disable(struct drm_bridge *bridge) +{ + struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge); + + if (sbridge->vdd) + regulator_disable(sbridge->vdd); +} + +static const struct drm_bridge_funcs simple_bridge_bridge_funcs = { + .attach = simple_bridge_attach, + .enable = simple_bridge_enable, + .disable = simple_bridge_disable, +}; + +static struct i2c_adapter *simple_bridge_retrieve_ddc(struct device *dev) +{ + struct device_node *phandle, *remote; + struct i2c_adapter *ddc; + + remote = of_graph_get_remote_node(dev->of_node, 1, -1); + if (!remote) + return ERR_PTR(-EINVAL); + + phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0); + of_node_put(remote); + if (!phandle) + return ERR_PTR(-ENODEV); + + ddc = of_get_i2c_adapter_by_node(phandle); + of_node_put(phandle); + if (!ddc) + return ERR_PTR(-EPROBE_DEFER); + + return ddc; +} + +static int simple_bridge_probe(struct platform_device *pdev) +{ + struct simple_bridge *sbridge; + + sbridge = devm_kzalloc(&pdev->dev, sizeof(*sbridge), GFP_KERNEL); + if (!sbridge) + return -ENOMEM; + platform_set_drvdata(pdev, sbridge); + + sbridge->vdd = devm_regulator_get_optional(&pdev->dev, "vdd"); + if (IS_ERR(sbridge->vdd)) { + int ret = PTR_ERR(sbridge->vdd); + if (ret == -EPROBE_DEFER) + return -EPROBE_DEFER; + sbridge->vdd = NULL; + dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret); + } + + sbridge->ddc = simple_bridge_retrieve_ddc(&pdev->dev); + if (IS_ERR(sbridge->ddc)) { + if (PTR_ERR(sbridge->ddc) == -ENODEV) { + dev_dbg(&pdev->dev, + "No i2c bus specified. Disabling EDID readout\n"); + sbridge->ddc = NULL; + } else { + dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n"); + return PTR_ERR(sbridge->ddc); + } + } + + sbridge->bridge.funcs = &simple_bridge_bridge_funcs; + sbridge->bridge.of_node = pdev->dev.of_node; + sbridge->bridge.timings = of_device_get_match_data(&pdev->dev); + + drm_bridge_add(&sbridge->bridge); + + return 0; +} + +static int simple_bridge_remove(struct platform_device *pdev) +{ + struct simple_bridge *sbridge = platform_get_drvdata(pdev); + + drm_bridge_remove(&sbridge->bridge); + + if (sbridge->ddc) + i2c_put_adapter(sbridge->ddc); + + return 0; +} + +/* + * We assume the ADV7123 DAC is the "default" for historical reasons + * Information taken from the ADV7123 datasheet, revision D. + * NOTE: the ADV7123EP seems to have other timings and need a new timings + * set if used. + */ +static const struct drm_bridge_timings default_bridge_timings = { + /* Timing specifications, datasheet page 7 */ + .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, + .setup_time_ps = 500, + .hold_time_ps = 1500, +}; + +/* + * Information taken from the THS8134, THS8134A, THS8134B datasheet named + * "SLVS205D", dated May 1990, revised March 2000. + */ +static const struct drm_bridge_timings ti_ths8134_bridge_timings = { + /* From timing diagram, datasheet page 9 */ + .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, + /* From datasheet, page 12 */ + .setup_time_ps = 3000, + /* I guess this means latched input */ + .hold_time_ps = 0, +}; + +/* + * Information taken from the THS8135 datasheet named "SLAS343B", dated + * May 2001, revised April 2013. + */ +static const struct drm_bridge_timings ti_ths8135_bridge_timings = { + /* From timing diagram, datasheet page 14 */ + .input_bus_flags = DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE, + /* From datasheet, page 16 */ + .setup_time_ps = 2000, + .hold_time_ps = 500, +}; + +static const struct of_device_id simple_bridge_match[] = { + { + .compatible = "dumb-vga-dac", + .data = NULL, + }, + { + .compatible = "adi,adv7123", + .data = &default_bridge_timings, + }, + { + .compatible = "ti,ths8135", + .data = &ti_ths8135_bridge_timings, + }, + { + .compatible = "ti,ths8134", + .data = &ti_ths8134_bridge_timings, + }, + {}, +}; +MODULE_DEVICE_TABLE(of, simple_bridge_match); + +static struct platform_driver simple_bridge_driver = { + .probe = simple_bridge_probe, + .remove = simple_bridge_remove, + .driver = { + .name = "simple-bridge", + .of_match_table = simple_bridge_match, + }, +}; +module_platform_driver(simple_bridge_driver); + +MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>"); +MODULE_DESCRIPTION("Simple DRM bridge driver"); +MODULE_LICENSE("GPL"); |