301 lines
7.4 KiB
C
301 lines
7.4 KiB
C
/*
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* Copyright (C) 2015-2016 Free Electrons
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* Copyright (C) 2015-2016 NextThing Co
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*
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/of_device.h>
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#include <linux/of_graph.h>
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#include <linux/regulator/consumer.h>
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#include <drm/drmP.h>
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#include <drm/drm_atomic_helper.h>
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#include <drm/drm_crtc.h>
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#include <drm/drm_crtc_helper.h>
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struct dumb_vga {
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struct drm_bridge bridge;
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struct drm_connector connector;
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struct i2c_adapter *ddc;
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struct regulator *vdd;
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};
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static inline struct dumb_vga *
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drm_bridge_to_dumb_vga(struct drm_bridge *bridge)
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{
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return container_of(bridge, struct dumb_vga, bridge);
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}
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static inline struct dumb_vga *
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drm_connector_to_dumb_vga(struct drm_connector *connector)
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{
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return container_of(connector, struct dumb_vga, connector);
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}
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static int dumb_vga_get_modes(struct drm_connector *connector)
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{
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struct dumb_vga *vga = drm_connector_to_dumb_vga(connector);
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struct edid *edid;
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int ret;
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if (IS_ERR(vga->ddc))
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goto fallback;
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edid = drm_get_edid(connector, vga->ddc);
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if (!edid) {
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DRM_INFO("EDID readout failed, falling back to standard modes\n");
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goto fallback;
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}
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drm_connector_update_edid_property(connector, edid);
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ret = drm_add_edid_modes(connector, edid);
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kfree(edid);
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return ret;
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fallback:
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/*
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* In case we cannot retrieve the EDIDs (broken or missing i2c
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* bus), fallback on the XGA standards
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*/
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ret = drm_add_modes_noedid(connector, 1920, 1200);
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/* And prefer a mode pretty much anyone can handle */
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drm_set_preferred_mode(connector, 1024, 768);
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return ret;
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}
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static const struct drm_connector_helper_funcs dumb_vga_con_helper_funcs = {
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.get_modes = dumb_vga_get_modes,
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};
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static enum drm_connector_status
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dumb_vga_connector_detect(struct drm_connector *connector, bool force)
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{
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struct dumb_vga *vga = drm_connector_to_dumb_vga(connector);
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/*
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* Even if we have an I2C bus, we can't assume that the cable
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* is disconnected if drm_probe_ddc fails. Some cables don't
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* wire the DDC pins, or the I2C bus might not be working at
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* all.
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*/
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if (!IS_ERR(vga->ddc) && drm_probe_ddc(vga->ddc))
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return connector_status_connected;
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return connector_status_unknown;
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}
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static const struct drm_connector_funcs dumb_vga_con_funcs = {
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.detect = dumb_vga_connector_detect,
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.fill_modes = drm_helper_probe_single_connector_modes,
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.destroy = drm_connector_cleanup,
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.reset = drm_atomic_helper_connector_reset,
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.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
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.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
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};
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static int dumb_vga_attach(struct drm_bridge *bridge)
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{
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struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
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int ret;
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if (!bridge->encoder) {
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DRM_ERROR("Missing encoder\n");
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return -ENODEV;
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}
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drm_connector_helper_add(&vga->connector,
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&dumb_vga_con_helper_funcs);
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ret = drm_connector_init(bridge->dev, &vga->connector,
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&dumb_vga_con_funcs, DRM_MODE_CONNECTOR_VGA);
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if (ret) {
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DRM_ERROR("Failed to initialize connector\n");
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return ret;
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}
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drm_connector_attach_encoder(&vga->connector,
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bridge->encoder);
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return 0;
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}
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static void dumb_vga_enable(struct drm_bridge *bridge)
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{
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struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
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int ret = 0;
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if (vga->vdd)
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ret = regulator_enable(vga->vdd);
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if (ret)
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DRM_ERROR("Failed to enable vdd regulator: %d\n", ret);
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}
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static void dumb_vga_disable(struct drm_bridge *bridge)
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{
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struct dumb_vga *vga = drm_bridge_to_dumb_vga(bridge);
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if (vga->vdd)
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regulator_disable(vga->vdd);
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}
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static const struct drm_bridge_funcs dumb_vga_bridge_funcs = {
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.attach = dumb_vga_attach,
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.enable = dumb_vga_enable,
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.disable = dumb_vga_disable,
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};
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static struct i2c_adapter *dumb_vga_retrieve_ddc(struct device *dev)
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{
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struct device_node *phandle, *remote;
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struct i2c_adapter *ddc;
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remote = of_graph_get_remote_node(dev->of_node, 1, -1);
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if (!remote)
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return ERR_PTR(-EINVAL);
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phandle = of_parse_phandle(remote, "ddc-i2c-bus", 0);
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of_node_put(remote);
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if (!phandle)
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return ERR_PTR(-ENODEV);
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ddc = of_get_i2c_adapter_by_node(phandle);
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of_node_put(phandle);
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if (!ddc)
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return ERR_PTR(-EPROBE_DEFER);
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return ddc;
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}
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static int dumb_vga_probe(struct platform_device *pdev)
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{
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struct dumb_vga *vga;
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vga = devm_kzalloc(&pdev->dev, sizeof(*vga), GFP_KERNEL);
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if (!vga)
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return -ENOMEM;
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platform_set_drvdata(pdev, vga);
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vga->vdd = devm_regulator_get_optional(&pdev->dev, "vdd");
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if (IS_ERR(vga->vdd)) {
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int ret = PTR_ERR(vga->vdd);
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if (ret == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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vga->vdd = NULL;
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dev_dbg(&pdev->dev, "No vdd regulator found: %d\n", ret);
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}
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vga->ddc = dumb_vga_retrieve_ddc(&pdev->dev);
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if (IS_ERR(vga->ddc)) {
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if (PTR_ERR(vga->ddc) == -ENODEV) {
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dev_dbg(&pdev->dev,
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"No i2c bus specified. Disabling EDID readout\n");
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} else {
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dev_err(&pdev->dev, "Couldn't retrieve i2c bus\n");
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return PTR_ERR(vga->ddc);
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}
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}
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vga->bridge.funcs = &dumb_vga_bridge_funcs;
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vga->bridge.of_node = pdev->dev.of_node;
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vga->bridge.timings = of_device_get_match_data(&pdev->dev);
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drm_bridge_add(&vga->bridge);
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return 0;
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}
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static int dumb_vga_remove(struct platform_device *pdev)
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{
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struct dumb_vga *vga = platform_get_drvdata(pdev);
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drm_bridge_remove(&vga->bridge);
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if (!IS_ERR(vga->ddc))
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i2c_put_adapter(vga->ddc);
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return 0;
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}
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/*
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* We assume the ADV7123 DAC is the "default" for historical reasons
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* Information taken from the ADV7123 datasheet, revision D.
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* NOTE: the ADV7123EP seems to have other timings and need a new timings
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* set if used.
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*/
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static const struct drm_bridge_timings default_dac_timings = {
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/* Timing specifications, datasheet page 7 */
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.sampling_edge = DRM_BUS_FLAG_PIXDATA_POSEDGE,
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.setup_time_ps = 500,
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.hold_time_ps = 1500,
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};
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/*
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* Information taken from the THS8134, THS8134A, THS8134B datasheet named
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* "SLVS205D", dated May 1990, revised March 2000.
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*/
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static const struct drm_bridge_timings ti_ths8134_dac_timings = {
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/* From timing diagram, datasheet page 9 */
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.sampling_edge = DRM_BUS_FLAG_PIXDATA_POSEDGE,
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/* From datasheet, page 12 */
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.setup_time_ps = 3000,
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/* I guess this means latched input */
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.hold_time_ps = 0,
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};
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/*
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* Information taken from the THS8135 datasheet named "SLAS343B", dated
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* May 2001, revised April 2013.
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*/
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static const struct drm_bridge_timings ti_ths8135_dac_timings = {
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/* From timing diagram, datasheet page 14 */
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.sampling_edge = DRM_BUS_FLAG_PIXDATA_POSEDGE,
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/* From datasheet, page 16 */
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.setup_time_ps = 2000,
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.hold_time_ps = 500,
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};
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static const struct of_device_id dumb_vga_match[] = {
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{
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.compatible = "dumb-vga-dac",
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.data = NULL,
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},
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{
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.compatible = "adi,adv7123",
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.data = &default_dac_timings,
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},
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{
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.compatible = "ti,ths8135",
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.data = &ti_ths8135_dac_timings,
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},
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{
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.compatible = "ti,ths8134",
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.data = &ti_ths8134_dac_timings,
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, dumb_vga_match);
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static struct platform_driver dumb_vga_driver = {
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.probe = dumb_vga_probe,
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.remove = dumb_vga_remove,
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.driver = {
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.name = "dumb-vga-dac",
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.of_match_table = dumb_vga_match,
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},
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};
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module_platform_driver(dumb_vga_driver);
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MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
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MODULE_DESCRIPTION("Dumb VGA DAC bridge driver");
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MODULE_LICENSE("GPL");
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