drm: bridge: icn6211: Add I2C configuration support

The ICN6211 chip starts in I2C configuration mode after cold boot.
Implement support for configuring the chip via I2C in addition to
the current DSI LP command mode configuration support. The later
seems to be available only on chips which have additional MCU on
the panel/bridge board which preconfigures the ICN6211, while the
I2C configuration mode added by this patch does not require any
such MCU.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
To: dri-devel@lists.freedesktop.org

drivers/gpu/drm/bridge/chipone-icn6211.c

@@ -11,6 +11,7 @@
 
 #include <linux/delay.h>
 #include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/regulator/consumer.h>
@@ -133,14 +134,17 @@
 
 struct chipone {
 	struct device *dev;
+	struct i2c_client *client;
 	struct drm_bridge bridge;
 	struct drm_bridge *panel_bridge;
 	struct device_node *host_node;
+	struct mipi_dsi_device *dsi;
 	struct gpio_desc *enable_gpio;
 	struct regulator *vdd1;
 	struct regulator *vdd2;
 	struct regulator *vdd3;
 	int dsi_lanes;
+	bool interface_i2c;
 };
 
 static inline struct chipone *bridge_to_chipone(struct drm_bridge *bridge)
@@ -172,20 +176,14 @@ bridge_to_mode(struct drm_bridge *bridge, struct drm_atomic_state *state)
 	return &crtc_state->adjusted_mode;
 }
 
-static inline int chipone_dsi_write(struct chipone *icn,  const void *seq,
-				    size_t len)
+static void ICN6211_DSI(struct chipone *icn, u8 reg, u8 val)
 {
-	struct mipi_dsi_device *dsi = to_mipi_dsi_device(icn->dev);
-
-	return mipi_dsi_generic_write(dsi, seq, len);
+	if (icn->interface_i2c)
+		i2c_smbus_write_byte_data(icn->client, reg, val);
+	else
+		mipi_dsi_generic_write(icn->dsi, (u8[]){reg, val}, 2);
 }
 
-#define ICN6211_DSI(icn, seq...)				\
-	{							\
-		const u8 d[] = { seq };				\
-		chipone_dsi_write(icn, d, ARRAY_SIZE(d));	\
-	}
-
 static void chipone_configure_pll(struct chipone *icn,
 				  const struct drm_display_mode *mode)
 {
@@ -282,7 +280,10 @@ static void chipone_atomic_enable(struct drm_bridge *bridge,
 	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
 	bus_flags = bridge_state->output_bus_cfg.flags;
 
-	ICN6211_DSI(icn, MIPI_CFG_PW, MIPI_CFG_PW_CONFIG_DSI);
+	if (icn->interface_i2c)
+		ICN6211_DSI(icn, MIPI_CFG_PW, MIPI_CFG_PW_CONFIG_I2C);
+	else
+		ICN6211_DSI(icn, MIPI_CFG_PW, MIPI_CFG_PW_CONFIG_DSI);
 
 	ICN6211_DSI(icn, HACTIVE_LI, mode->hdisplay & 0xff);
 
@@ -396,11 +397,86 @@ static void chipone_atomic_post_disable(struct drm_bridge *bridge,
 	gpiod_set_value(icn->enable_gpio, 0);
 }
 
+static int chipone_dsi_attach(struct chipone *icn)
+{
+	struct mipi_dsi_device *dsi = icn->dsi;
+	int ret;
+
+	dsi->lanes = icn->dsi_lanes;
+	dsi->format = MIPI_DSI_FMT_RGB888;
+	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
+			  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_NO_EOT_PACKET;
+
+	ret = mipi_dsi_attach(dsi);
+	if (ret < 0)
+		dev_err(icn->dev, "failed to attach dsi\n");
+
+	return ret;
+}
+
+static int chipone_dsi_setup(struct chipone *icn)
+{
+	struct device *dev = icn->dev;
+	struct mipi_dsi_device *dsi;
+	struct mipi_dsi_host *host;
+	int ret = 0;
+
+	const struct mipi_dsi_device_info info = {
+		.type = "chipone",
+		.channel = 0,
+		.node = NULL,
+	};
+
+	host = of_find_mipi_dsi_host_by_node(icn->host_node);
+	if (!host) {
+		dev_err(dev, "failed to find dsi host\n");
+		return -EPROBE_DEFER;
+	}
+
+	dsi = mipi_dsi_device_register_full(host, &info);
+	if (IS_ERR(dsi)) {
+		return dev_err_probe(dev, PTR_ERR(dsi),
+				     "failed to create dsi device\n");
+	}
+
+	icn->dsi = dsi;
+
+	ret = chipone_dsi_attach(icn);
+	if (ret < 0)
+		mipi_dsi_device_unregister(dsi);
+
+	return ret;
+}
+
 static int chipone_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags)
 {
 	struct chipone *icn = bridge_to_chipone(bridge);
+	struct drm_bridge *abridge = bridge;
+	int ret;
+
+	if (icn->interface_i2c) {
+		ret = chipone_dsi_setup(icn);
+		if (ret)
+			return ret;
+
+		abridge = &icn->bridge;
+	}
+
+	return drm_bridge_attach(bridge->encoder, icn->panel_bridge,
+				 bridge, flags);
+}
+
+static void chipone_detach(struct drm_bridge *bridge)
+{
+	struct chipone *icn = bridge_to_chipone(bridge);
+
+	if (!icn->dsi || icn->interface_i2c)
+		return;
 
-	return drm_bridge_attach(bridge->encoder, icn->panel_bridge, bridge, flags);
+	mipi_dsi_detach(icn->dsi);
+	mipi_dsi_device_unregister(icn->dsi);
+	drm_bridge_remove(&icn->bridge);
+	icn->dsi = NULL;
 }
 
 #define MAX_INPUT_SEL_FORMATS	1
@@ -431,6 +507,7 @@ chipone_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 
 static const struct drm_bridge_funcs chipone_bridge_funcs = {
 	.attach = chipone_attach,
+	.detach = chipone_detach,
 	.atomic_post_disable = chipone_atomic_post_disable,
 	.atomic_pre_enable = chipone_atomic_pre_enable,
 	.atomic_enable = chipone_atomic_enable,
@@ -505,17 +582,15 @@ static int chipone_parse_dt(struct chipone *icn)
 	return 0;
 }
 
-static int chipone_probe(struct mipi_dsi_device *dsi)
+static int chipone_common_probe(struct device *dev, struct chipone **icnr)
 {
-	struct device *dev = &dsi->dev;
 	struct chipone *icn;
 	int ret;
 
 	icn = devm_kzalloc(dev, sizeof(struct chipone), GFP_KERNEL);
 	if (!icn)
 		return -ENOMEM;
 
-	mipi_dsi_set_drvdata(dsi, icn);
 	icn->dev = dev;
 
 	ret = chipone_parse_dt(icn);
@@ -526,29 +601,77 @@ static int chipone_probe(struct mipi_dsi_device *dsi)
 	icn->bridge.type = DRM_MODE_CONNECTOR_DPI;
 	icn->bridge.of_node = dev->of_node;
 
-	drm_bridge_add(&icn->bridge);
+	*icnr = icn;
 
-	dsi->lanes = icn->dsi_lanes;
-	dsi->format = MIPI_DSI_FMT_RGB888;
-	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
-			  MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_NO_EOT_PACKET;
+	return ret;
+}
 
-	ret = mipi_dsi_attach(dsi);
-	if (ret < 0) {
+static int chipone_dsi_probe(struct mipi_dsi_device *dsi)
+{
+	struct device *dev = &dsi->dev;
+	struct chipone *icn;
+	int ret;
+
+	ret = chipone_common_probe(dev, &icn);
+	if (ret)
+		return ret;
+
+	icn->interface_i2c = false;
+	icn->dsi = dsi;
+
+	mipi_dsi_set_drvdata(dsi, icn);
+
+	drm_bridge_add(&icn->bridge);
+
+	ret = chipone_dsi_attach(icn);
+	if (ret)
 		drm_bridge_remove(&icn->bridge);
-		dev_err(dev, "failed to attach dsi\n");
-	}
 
 	return ret;
 }
 
-static int chipone_remove(struct mipi_dsi_device *dsi)
+static int chipone_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct chipone *icn;
+	int ret;
+
+	ret = chipone_common_probe(dev, &icn);
+	if (ret)
+		return ret;
+
+	icn->interface_i2c = true;
+	icn->client = client;
+	dev_set_drvdata(dev, icn);
+	i2c_set_clientdata(client, icn);
+
+	drm_bridge_add(&icn->bridge);
+
+	return ret;
+}
+
+static void chipone_common_remove(struct chipone *icn)
+{
+	of_node_put(icn->host_node);
+}
+
+static int chipone_dsi_remove(struct mipi_dsi_device *dsi)
 {
 	struct chipone *icn = mipi_dsi_get_drvdata(dsi);
 
 	mipi_dsi_detach(dsi);
 	drm_bridge_remove(&icn->bridge);
-	of_node_put(icn->host_node);
+	chipone_common_remove(icn);
+
+	return 0;
+}
+
+static int chipone_i2c_remove(struct i2c_client *client)
+{
+	struct chipone *icn = i2c_get_clientdata(client);
+
+	chipone_common_remove(icn);
 
 	return 0;
 }
@@ -559,16 +682,50 @@ static const struct of_device_id chipone_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, chipone_of_match);
 
-static struct mipi_dsi_driver chipone_driver = {
-	.probe = chipone_probe,
-	.remove = chipone_remove,
+static struct mipi_dsi_driver chipone_dsi_driver = {
+	.probe = chipone_dsi_probe,
+	.remove = chipone_dsi_remove,
 	.driver = {
 		.name = "chipone-icn6211",
 		.owner = THIS_MODULE,
 		.of_match_table = chipone_of_match,
 	},
 };
-module_mipi_dsi_driver(chipone_driver);
+
+static struct i2c_device_id chipone_i2c_id[] = {
+	{ "chipone,icn6211" },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, chipone_i2c_id);
+
+static struct i2c_driver chipone_i2c_driver = {
+	.probe = chipone_i2c_probe,
+	.remove = chipone_i2c_remove,
+	.id_table = chipone_i2c_id,
+	.driver = {
+		.name = "chipone-icn6211-i2c",
+		.owner = THIS_MODULE,
+		.of_match_table = chipone_of_match,
+	},
+};
+
+static int __init chipone_init(void)
+{
+	if (IS_ENABLED(CONFIG_DRM_MIPI_DSI))
+		mipi_dsi_driver_register(&chipone_dsi_driver);
+
+	return i2c_add_driver(&chipone_i2c_driver);
+}
+module_init(chipone_init);
+
+static void __init chipone_exit(void)
+{
+	i2c_del_driver(&chipone_i2c_driver);
+
+	if (IS_ENABLED(CONFIG_DRM_MIPI_DSI))
+		mipi_dsi_driver_unregister(&chipone_dsi_driver);
+}
+module_exit(chipone_exit);
 
 MODULE_AUTHOR("Jagan Teki <jagan@amarulasolutions.com>");
 MODULE_DESCRIPTION("Chipone ICN6211 MIPI-DSI to RGB Converter Bridge");