[PATCH 03/11] drm: add driver for simple vga encoders

[Heiko Stuebner <heiko@sntech.de>]

There exist simple vga encoders without any type of management interface
and just maybe a simple gpio for turning it on or off. Examples for these
are the Analog Devices ADV7123, Chipsea CS7123 or Micronas SDA7123.

Add a generic encoder driver for those that can be used by drm drivers
using the component framework.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/gpu/drm/i2c/Kconfig      |   6 +
 drivers/gpu/drm/i2c/Makefile     |   2 +
 drivers/gpu/drm/i2c/vga-simple.c | 325 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 333 insertions(+)
 create mode 100644 drivers/gpu/drm/i2c/vga-simple.c

diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
index 22c7ed6..319f2cb 100644
--- a/drivers/gpu/drm/i2c/Kconfig
+++ b/drivers/gpu/drm/i2c/Kconfig
@@ -31,4 +31,10 @@ config DRM_I2C_NXP_TDA998X
 	help
 	  Support for NXP Semiconductors TDA998X HDMI encoders.
 
+config DRM_VGA_SIMPLE
+	tristate "Generic simple vga encoder"
+	help
+	  Support for vga encoder chips without any special settings
+	  and at most a power-control gpio.
+
 endmenu
diff --git a/drivers/gpu/drm/i2c/Makefile b/drivers/gpu/drm/i2c/Makefile
index 2c72eb5..858961f 100644
--- a/drivers/gpu/drm/i2c/Makefile
+++ b/drivers/gpu/drm/i2c/Makefile
@@ -10,3 +10,5 @@ obj-$(CONFIG_DRM_I2C_SIL164) += sil164.o
 
 tda998x-y := tda998x_drv.o
 obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o
+
+obj-$(CONFIG_DRM_VGA_SIMPLE) += vga-simple.o
diff --git a/drivers/gpu/drm/i2c/vga-simple.c b/drivers/gpu/drm/i2c/vga-simple.c
new file mode 100644
index 0000000..bb9d19c
--- /dev/null
+++ b/drivers/gpu/drm/i2c/vga-simple.c
@@ -0,0 +1,325 @@
+/*
+ * Simple vga encoder driver
+ *
+ * Copyright (C) 2014 Heiko Stuebner <heiko@sntech.de>
+ *
+ * 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/module.h>
+#include <linux/component.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/regulator/consumer.h>
+#include <drm/drm_of.h>
+#include <drm/drmP.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_edid.h>
+
+#define connector_to_vga_simple(x) container_of(x, struct vga_simple, connector)
+#define encoder_to_vga_simple(x) container_of(x, struct vga_simple, encoder)
+
+struct vga_simple {
+	struct drm_connector connector;
+	struct drm_encoder encoder;
+
+	struct device *dev;
+	struct i2c_adapter *ddc;
+
+	struct regulator *vaa_reg;
+	struct gpio_desc *enable_gpio;
+
+	struct mutex enable_lock;
+	bool enabled;
+};
+
+/*
+ * Connector functions
+ */
+
+enum drm_connector_status vga_simple_detect(struct drm_connector *connector,
+					    bool force)
+{
+	struct vga_simple *vga = connector_to_vga_simple(connector);
+
+	if (!vga->ddc)
+		return connector_status_unknown;
+
+	if (drm_probe_ddc(vga->ddc))
+		return connector_status_connected;
+
+	return connector_status_disconnected;
+}
+
+void vga_simple_connector_destroy(struct drm_connector *connector)
+{
+	drm_connector_unregister(connector);
+	drm_connector_cleanup(connector);
+}
+
+struct drm_connector_funcs vga_simple_connector_funcs = {
+	.dpms = drm_helper_connector_dpms,
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.detect = vga_simple_detect,
+	.destroy = vga_simple_connector_destroy,
+};
+
+/*
+ * Connector helper functions
+ */
+
+static int vga_simple_connector_get_modes(struct drm_connector *connector)
+{
+	struct vga_simple *vga = connector_to_vga_simple(connector);
+	struct edid *edid;
+	int ret = 0;
+
+	if (!vga->ddc)
+		return 0;
+
+	edid = drm_get_edid(connector, vga->ddc);
+	if (edid) {
+		drm_mode_connector_update_edid_property(connector, edid);
+		ret = drm_add_edid_modes(connector, edid);
+		kfree(edid);
+	}
+
+	return ret;
+}
+
+static int vga_simple_connector_mode_valid(struct drm_connector *connector,
+					struct drm_display_mode *mode)
+{
+	return MODE_OK;
+}
+
+static struct drm_encoder
+*vga_simple_connector_best_encoder(struct drm_connector *connector)
+{
+	struct vga_simple *vga = connector_to_vga_simple(connector);
+
+	return &vga->encoder;
+}
+
+static struct drm_connector_helper_funcs vga_simple_connector_helper_funcs = {
+	.get_modes = vga_simple_connector_get_modes,
+	.best_encoder = vga_simple_connector_best_encoder,
+	.mode_valid = vga_simple_connector_mode_valid,
+};
+
+/*
+ * Encoder functions
+ */
+
+static void vga_simple_encoder_destroy(struct drm_encoder *encoder)
+{
+	drm_encoder_cleanup(encoder);
+}
+
+static const struct drm_encoder_funcs vga_simple_encoder_funcs = {
+	.destroy = vga_simple_encoder_destroy,
+};
+
+/*
+ * Encoder helper functions
+ */
+
+static void vga_simple_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+	struct vga_simple *vga = encoder_to_vga_simple(encoder);
+
+	mutex_lock(&vga->enable_lock);
+
+	switch (mode) {
+	case DRM_MODE_DPMS_ON:
+		if (vga->enabled)
+			goto out;
+
+		if (!IS_ERR(vga->vaa_reg))
+			regulator_enable(vga->vaa_reg);
+
+		if (vga->enable_gpio)
+			gpiod_set_value(vga->enable_gpio, 1);
+
+		vga->enabled = true;
+		break;
+	case DRM_MODE_DPMS_STANDBY:
+	case DRM_MODE_DPMS_SUSPEND:
+	case DRM_MODE_DPMS_OFF:
+		if (!vga->enabled)
+			goto out;
+
+		if (vga->enable_gpio)
+			gpiod_set_value(vga->enable_gpio, 0);
+
+		if (!IS_ERR(vga->vaa_reg))
+			regulator_enable(vga->vaa_reg);
+
+		vga->enabled = false;
+		break;
+	default:
+		break;
+	}
+
+out:
+	mutex_unlock(&vga->enable_lock);
+}
+
+static bool vga_simple_mode_fixup(struct drm_encoder *encoder,
+				  const struct drm_display_mode *mode,
+				  struct drm_display_mode *adjusted_mode)
+{
+	return true;
+}
+
+static void vga_simple_encoder_prepare(struct drm_encoder *encoder)
+{
+}
+
+static void vga_simple_encoder_mode_set(struct drm_encoder *encoder,
+					struct drm_display_mode *mode,
+					struct drm_display_mode *adjusted_mode)
+{
+}
+
+static void vga_simple_encoder_commit(struct drm_encoder *encoder)
+{
+	vga_simple_encoder_dpms(encoder, DRM_MODE_DPMS_ON);
+}
+
+static void vga_simple_encoder_disable(struct drm_encoder *encoder)
+{
+	vga_simple_encoder_dpms(encoder, DRM_MODE_DPMS_OFF);
+}
+
+static const struct drm_encoder_helper_funcs vga_simple_encoder_helper_funcs = {
+	.dpms = vga_simple_encoder_dpms,
+	.mode_fixup = vga_simple_mode_fixup,
+	.prepare = vga_simple_encoder_prepare,
+	.mode_set = vga_simple_encoder_mode_set,
+	.commit = vga_simple_encoder_commit,
+	.disable = vga_simple_encoder_disable,
+};
+
+/*
+ * Component helper functions
+ */
+
+static int vga_simple_bind(struct device *dev, struct device *master,
+				 void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct drm_device *drm = data;
+
+	struct device_node *ddc_node, *np = pdev->dev.of_node;
+	struct vga_simple *vga;
+	int ret;
+
+	if (!np)
+		return -ENODEV;
+
+	vga = devm_kzalloc(dev, sizeof(*vga), GFP_KERNEL);
+	if (!vga)
+		return -ENOMEM;
+
+	vga->dev = dev;
+	dev_set_drvdata(dev, vga);
+	mutex_init(&vga->enable_lock);
+
+	vga->enable_gpio = devm_gpiod_get_optional(dev, "enable",
+						   GPIOD_OUT_LOW);
+	if (IS_ERR(vga->enable_gpio)) {
+		ret = PTR_ERR(vga->enable_gpio);
+		dev_err(dev, "failed to request GPIO: %d\n", ret);
+		return ret;
+	}
+
+	vga->enabled = false;
+
+	ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
+	if (ddc_node) {
+		vga->ddc = of_find_i2c_adapter_by_node(ddc_node);
+		of_node_put(ddc_node);
+		if (!vga->ddc) {
+			dev_dbg(vga->dev, "failed to read ddc node\n");
+			return -EPROBE_DEFER;
+		}
+	} else {
+		dev_dbg(vga->dev, "no ddc property found\n");
+	}
+
+	vga->vaa_reg = devm_regulator_get_optional(dev, "vaa");
+
+	vga->encoder.possible_crtcs = drm_of_find_possible_crtcs(drm, np);
+	vga->encoder.of_node = np;
+	vga->connector.polled = DRM_CONNECTOR_POLL_CONNECT |
+				DRM_CONNECTOR_POLL_DISCONNECT;
+
+	drm_encoder_helper_add(&vga->encoder, &vga_simple_encoder_helper_funcs);
+	drm_encoder_init(drm, &vga->encoder, &vga_simple_encoder_funcs,
+			 DRM_MODE_ENCODER_DAC);
+
+	drm_connector_helper_add(&vga->connector,
+				 &vga_simple_connector_helper_funcs);
+	drm_connector_init(drm, &vga->connector, &vga_simple_connector_funcs,
+			   DRM_MODE_CONNECTOR_VGA);
+
+	drm_mode_connector_attach_encoder(&vga->connector, &vga->encoder);
+
+	return 0;
+}
+
+static void vga_simple_unbind(struct device *dev, struct device *master,
+				    void *data)
+{
+	struct vga_simple *vga = dev_get_drvdata(dev);
+
+	vga->connector.funcs->destroy(&vga->connector);
+	vga->encoder.funcs->destroy(&vga->encoder);
+}
+
+static const struct component_ops vga_simple_ops = {
+	.bind = vga_simple_bind,
+	.unbind = vga_simple_unbind,
+};
+
+static int vga_simple_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &vga_simple_ops);
+}
+
+static int vga_simple_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &vga_simple_ops);
+
+	return 0;
+}
+
+static const struct of_device_id vga_simple_ids[] = {
+	{ .compatible = "adi,adv7123", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, vga_simple_ids);
+
+static struct platform_driver vga_simple_driver = {
+	.probe  = vga_simple_probe,
+	.remove = vga_simple_remove,
+	.driver = {
+		.name = "vga-simple",
+		.of_match_table = vga_simple_ids,
+	},
+};
+module_platform_driver(vga_simple_driver);
+
+MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
+MODULE_DESCRIPTION("Simple vga converter");
+MODULE_LICENSE("GPL");
-- 
2.1.1

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