1 files changed, 178 insertions, 69 deletions

diff --git a/drivers/gpu/drm/bridge/sii902x.c b/drivers/gpu/drm/bridge/sii902x.c
index e59a13542333..bfa902013aa4 100644
--- a/drivers/gpu/drm/bridge/sii902x.c
+++ b/drivers/gpu/drm/bridge/sii902x.c
@@ -1,4 +1,6 @@
 /*
+ * Copyright (C) 2018 Renesas Electronics
+ *
  * Copyright (C) 2016 Atmel
  *		      Bo Shen <voice.shen@atmel.com>
  *
@@ -21,6 +23,7 @@
  */
 
 #include <linux/gpio/consumer.h>
+#include <linux/i2c-mux.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
@@ -86,8 +89,49 @@ struct sii902x {
 	struct drm_bridge bridge;
 	struct drm_connector connector;
 	struct gpio_desc *reset_gpio;
+	struct i2c_mux_core *i2cmux;
 };
 
+static int sii902x_read_unlocked(struct i2c_client *i2c, u8 reg, u8 *val)
+{
+	union i2c_smbus_data data;
+	int ret;
+
+	ret = __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,
+			       I2C_SMBUS_READ, reg, I2C_SMBUS_BYTE_DATA, &data);
+
+	if (ret < 0)
+		return ret;
+
+	*val = data.byte;
+	return 0;
+}
+
+static int sii902x_write_unlocked(struct i2c_client *i2c, u8 reg, u8 val)
+{
+	union i2c_smbus_data data;
+
+	data.byte = val;
+
+	return __i2c_smbus_xfer(i2c->adapter, i2c->addr, i2c->flags,
+				I2C_SMBUS_WRITE, reg, I2C_SMBUS_BYTE_DATA,
+				&data);
+}
+
+static int sii902x_update_bits_unlocked(struct i2c_client *i2c, u8 reg, u8 mask,
+					u8 val)
+{
+	int ret;
+	u8 status;
+
+	ret = sii902x_read_unlocked(i2c, reg, &status);
+	if (ret)
+		return ret;
+	status &= ~mask;
+	status |= val & mask;
+	return sii902x_write_unlocked(i2c, reg, status);
+}
+
 static inline struct sii902x *bridge_to_sii902x(struct drm_bridge *bridge)
 {
 	return container_of(bridge, struct sii902x, bridge);
@@ -135,41 +179,11 @@ static const struct drm_connector_funcs sii902x_connector_funcs = {
 static int sii902x_get_modes(struct drm_connector *connector)
 {
 	struct sii902x *sii902x = connector_to_sii902x(connector);
-	struct regmap *regmap = sii902x->regmap;
 	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
-	struct device *dev = &sii902x->i2c->dev;
-	unsigned long timeout;
-	unsigned int retries;
-	unsigned int status;
 	struct edid *edid;
-	int num = 0;
-	int ret;
-
-	ret = regmap_update_bits(regmap, SII902X_SYS_CTRL_DATA,
-				 SII902X_SYS_CTRL_DDC_BUS_REQ,
-				 SII902X_SYS_CTRL_DDC_BUS_REQ);
-	if (ret)
-		return ret;
-
-	timeout = jiffies +
-		  msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);
-	do {
-		ret = regmap_read(regmap, SII902X_SYS_CTRL_DATA, &status);
-		if (ret)
-			return ret;
-	} while (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD) &&
-		 time_before(jiffies, timeout));
+	int num = 0, ret;
 
-	if (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD)) {
-		dev_err(dev, "failed to acquire the i2c bus\n");
-		return -ETIMEDOUT;
-	}
-
-	ret = regmap_write(regmap, SII902X_SYS_CTRL_DATA, status);
-	if (ret)
-		return ret;
-
-	edid = drm_get_edid(connector, sii902x->i2c->adapter);
+	edid = drm_get_edid(connector, sii902x->i2cmux->adapter[0]);
 	drm_connector_update_edid_property(connector, edid);
 	if (edid) {
 		num = drm_add_edid_modes(connector, edid);
@@ -181,42 +195,6 @@ static int sii902x_get_modes(struct drm_connector *connector)
 	if (ret)
 		return ret;
 
-	/*
-	 * Sometimes the I2C bus can stall after failure to use the
-	 * EDID channel. Retry a few times to see if things clear
-	 * up, else continue anyway.
-	 */
-	retries = 5;
-	do {
-		ret = regmap_read(regmap, SII902X_SYS_CTRL_DATA,
-				  &status);
-		retries--;
-	} while (ret && retries);
-	if (ret)
-		dev_err(dev, "failed to read status (%d)\n", ret);
-
-	ret = regmap_update_bits(regmap, SII902X_SYS_CTRL_DATA,
-				 SII902X_SYS_CTRL_DDC_BUS_REQ |
-				 SII902X_SYS_CTRL_DDC_BUS_GRTD, 0);
-	if (ret)
-		return ret;
-
-	timeout = jiffies +
-		  msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);
-	do {
-		ret = regmap_read(regmap, SII902X_SYS_CTRL_DATA, &status);
-		if (ret)
-			return ret;
-	} while (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |
-			   SII902X_SYS_CTRL_DDC_BUS_GRTD) &&
-		 time_before(jiffies, timeout));
-
-	if (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |
-		      SII902X_SYS_CTRL_DDC_BUS_GRTD)) {
-		dev_err(dev, "failed to release the i2c bus\n");
-		return -ETIMEDOUT;
-	}
-
 	return num;
 }
 
@@ -366,6 +344,121 @@ static irqreturn_t sii902x_interrupt(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+/*
+ * The purpose of sii902x_i2c_bypass_select is to enable the pass through
+ * mode of the HDMI transmitter. Do not use regmap from within this function,
+ * only use sii902x_*_unlocked functions to read/modify/write registers.
+ * We are holding the parent adapter lock here, keep this in mind before
+ * adding more i2c transactions.
+ *
+ * Also, since SII902X_SYS_CTRL_DATA is used with regmap_update_bits elsewhere
+ * in this driver, we need to make sure that we only touch 0x1A[2:1] from
+ * within sii902x_i2c_bypass_select and sii902x_i2c_bypass_deselect, and that
+ * we leave the remaining bits as we have found them.
+ */
+static int sii902x_i2c_bypass_select(struct i2c_mux_core *mux, u32 chan_id)
+{
+	struct sii902x *sii902x = i2c_mux_priv(mux);
+	struct device *dev = &sii902x->i2c->dev;
+	unsigned long timeout;
+	u8 status;
+	int ret;
+
+	ret = sii902x_update_bits_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+					   SII902X_SYS_CTRL_DDC_BUS_REQ,
+					   SII902X_SYS_CTRL_DDC_BUS_REQ);
+	if (ret)
+		return ret;
+
+	timeout = jiffies +
+		  msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);
+	do {
+		ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+					    &status);
+		if (ret)
+			return ret;
+	} while (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD) &&
+		 time_before(jiffies, timeout));
+
+	if (!(status & SII902X_SYS_CTRL_DDC_BUS_GRTD)) {
+		dev_err(dev, "Failed to acquire the i2c bus\n");
+		return -ETIMEDOUT;
+	}
+
+	return sii902x_write_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+				      status);
+}
+
+/*
+ * The purpose of sii902x_i2c_bypass_deselect is to disable the pass through
+ * mode of the HDMI transmitter. Do not use regmap from within this function,
+ * only use sii902x_*_unlocked functions to read/modify/write registers.
+ * We are holding the parent adapter lock here, keep this in mind before
+ * adding more i2c transactions.
+ *
+ * Also, since SII902X_SYS_CTRL_DATA is used with regmap_update_bits elsewhere
+ * in this driver, we need to make sure that we only touch 0x1A[2:1] from
+ * within sii902x_i2c_bypass_select and sii902x_i2c_bypass_deselect, and that
+ * we leave the remaining bits as we have found them.
+ */
+static int sii902x_i2c_bypass_deselect(struct i2c_mux_core *mux, u32 chan_id)
+{
+	struct sii902x *sii902x = i2c_mux_priv(mux);
+	struct device *dev = &sii902x->i2c->dev;
+	unsigned long timeout;
+	unsigned int retries;
+	u8 status;
+	int ret;
+
+	/*
+	 * When the HDMI transmitter is in pass through mode, we need an
+	 * (undocumented) additional delay between STOP and START conditions
+	 * to guarantee the bus won't get stuck.
+	 */
+	udelay(30);
+
+	/*
+	 * Sometimes the I2C bus can stall after failure to use the
+	 * EDID channel. Retry a few times to see if things clear
+	 * up, else continue anyway.
+	 */
+	retries = 5;
+	do {
+		ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+					    &status);
+		retries--;
+	} while (ret && retries);
+	if (ret) {
+		dev_err(dev, "failed to read status (%d)\n", ret);
+		return ret;
+	}
+
+	ret = sii902x_update_bits_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+					   SII902X_SYS_CTRL_DDC_BUS_REQ |
+					   SII902X_SYS_CTRL_DDC_BUS_GRTD, 0);
+	if (ret)
+		return ret;
+
+	timeout = jiffies +
+		  msecs_to_jiffies(SII902X_I2C_BUS_ACQUISITION_TIMEOUT_MS);
+	do {
+		ret = sii902x_read_unlocked(sii902x->i2c, SII902X_SYS_CTRL_DATA,
+					    &status);
+		if (ret)
+			return ret;
+	} while (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |
+			   SII902X_SYS_CTRL_DDC_BUS_GRTD) &&
+		 time_before(jiffies, timeout));
+
+	if (status & (SII902X_SYS_CTRL_DDC_BUS_REQ |
+		      SII902X_SYS_CTRL_DDC_BUS_GRTD)) {
+		dev_err(dev, "failed to release the i2c bus\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
 static int sii902x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -375,6 +468,13 @@ static int sii902x_probe(struct i2c_client *client,
 	u8 chipid[4];
 	int ret;
 
+	ret = i2c_check_functionality(client->adapter,
+				      I2C_FUNC_SMBUS_BYTE_DATA);
+	if (!ret) {
+		dev_err(dev, "I2C adapter not suitable\n");
+		return -EIO;
+	}
+
 	sii902x = devm_kzalloc(dev, sizeof(*sii902x), GFP_KERNEL);
 	if (!sii902x)
 		return -ENOMEM;
@@ -433,7 +533,15 @@ static int sii902x_probe(struct i2c_client *client,
 
 	i2c_set_clientdata(client, sii902x);
 
-	return 0;
+	sii902x->i2cmux = i2c_mux_alloc(client->adapter, dev,
+					1, 0, I2C_MUX_GATE,
+					sii902x_i2c_bypass_select,
+					sii902x_i2c_bypass_deselect);
+	if (!sii902x->i2cmux)
+		return -ENOMEM;
+
+	sii902x->i2cmux->priv = sii902x;
+	return i2c_mux_add_adapter(sii902x->i2cmux, 0, 0, 0);
 }
 
 static int sii902x_remove(struct i2c_client *client)
@@ -441,6 +549,7 @@ static int sii902x_remove(struct i2c_client *client)
 {
 	struct sii902x *sii902x = i2c_get_clientdata(client);
 
+	i2c_mux_del_adapters(sii902x->i2cmux);
 	drm_bridge_remove(&sii902x->bridge);
 
 	return 0;