tegra: i2c: Add function to know about current bus

Rather than using a variable in various places, add a single function,
tegra_i2c_get_bus(), which returns a pointer to information about a
bus.

This will make it easier to move to the new i2c framework.

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/i2c/tegra_i2c.c

@@ -284,7 +284,8 @@ exit:
 	return error;
 }
 
-static int tegra_i2c_write_data(u32 addr, u8 *data, u32 len)
+static int tegra_i2c_write_data(struct i2c_bus *bus, u32 addr, u8 *data,
+				u32 len)
 {
 	int error;
 	struct i2c_trans_info trans_info;
@@ -295,14 +296,15 @@ static int tegra_i2c_write_data(u32 addr, u8 *data, u32 len)
 	trans_info.num_bytes = len;
 	trans_info.is_10bit_address = 0;
 
-	error = send_recv_packets(&i2c_controllers[i2c_bus_num], &trans_info);
+	error = send_recv_packets(bus, &trans_info);
 	if (error)
 		debug("tegra_i2c_write_data: Error (%d) !!!\n", error);
 
 	return error;
 }
 
-static int tegra_i2c_read_data(u32 addr, u8 *data, u32 len)
+static int tegra_i2c_read_data(struct i2c_bus *bus, u32 addr, u8 *data,
+			       u32 len)
 {
 	int error;
 	struct i2c_trans_info trans_info;
@@ -313,7 +315,7 @@ static int tegra_i2c_read_data(u32 addr, u8 *data, u32 len)
 	trans_info.num_bytes = len;
 	trans_info.is_10bit_address = 0;
 
-	error = send_recv_packets(&i2c_controllers[i2c_bus_num], &trans_info);
+	error = send_recv_packets(bus, &trans_info);
 	if (error)
 		debug("tegra_i2c_read_data: Error (%d) !!!\n", error);
 
@@ -324,18 +326,48 @@ static int tegra_i2c_read_data(u32 addr, u8 *data, u32 len)
 #error "Please enable device tree support to use this driver"
 #endif
 
+/**
+ * Check that a bus number is valid and return a pointer to it
+ *
+ * @param bus_num	Bus number to check / return
+ * @return pointer to bus, if valid, else NULL
+ */
+static struct i2c_bus *tegra_i2c_get_bus(unsigned int bus_num)
+{
+	struct i2c_bus *bus;
+
+	if (bus_num >= TEGRA_I2C_NUM_CONTROLLERS) {
+		debug("%s: Invalid bus number %u\n", __func__, bus_num);
+		return NULL;
+	}
+	bus = &i2c_controllers[bus_num];
+	if (!bus->inited) {
+		debug("%s: Bus %u not available\n", __func__, bus_num);
+		return NULL;
+	}
+
+	return bus;
+}
+
 unsigned int i2c_get_bus_speed(void)
 {
-	return i2c_controllers[i2c_bus_num].speed;
+	struct i2c_bus *bus;
+
+	bus = tegra_i2c_get_bus(i2c_bus_num);
+	if (!bus)
+		return 0;
+	return bus->speed;
 }
 
 int i2c_set_bus_speed(unsigned int speed)
 {
-	struct i2c_bus *i2c_bus;
+	struct i2c_bus *bus;
 
-	i2c_bus = &i2c_controllers[i2c_bus_num];
-	i2c_bus->speed = speed;
-	i2c_init_controller(i2c_bus);
+	bus = tegra_i2c_get_bus(i2c_bus_num);
+	if (!bus)
+		return 0;
+	bus->speed = speed;
+	i2c_init_controller(bus);
 
 	return 0;
 }
@@ -458,7 +490,7 @@ void i2c_init(int speed, int slaveaddr)
 }
 
 /* i2c write version without the register address */
-int i2c_write_data(uchar chip, uchar *buffer, int len)
+int i2c_write_data(struct i2c_bus *bus, uchar chip, uchar *buffer, int len)
 {
 	int rc;
 
@@ -470,7 +502,7 @@ int i2c_write_data(uchar chip, uchar *buffer, int len)
 	debug("\n");
 
 	/* Shift 7-bit address over for lower-level i2c functions */
-	rc = tegra_i2c_write_data(chip << 1, buffer, len);
+	rc = tegra_i2c_write_data(bus, chip << 1, buffer, len);
 	if (rc)
 		debug("i2c_write_data(): rc=%d\n", rc);
 
@@ -478,13 +510,13 @@ int i2c_write_data(uchar chip, uchar *buffer, int len)
 }
 
 /* i2c read version without the register address */
-int i2c_read_data(uchar chip, uchar *buffer, int len)
+int i2c_read_data(struct i2c_bus *bus, uchar chip, uchar *buffer, int len)
 {
 	int rc;
 
 	debug("inside i2c_read_data():\n");
 	/* Shift 7-bit address over for lower-level i2c functions */
-	rc = tegra_i2c_read_data(chip << 1, buffer, len);
+	rc = tegra_i2c_read_data(bus, chip << 1, buffer, len);
 	if (rc) {
 		debug("i2c_read_data(): rc=%d\n", rc);
 		return rc;
@@ -502,12 +534,16 @@ int i2c_read_data(uchar chip, uchar *buffer, int len)
 /* Probe to see if a chip is present. */
 int i2c_probe(uchar chip)
 {
+	struct i2c_bus *bus;
 	int rc;
 	uchar reg;
 
 	debug("i2c_probe: addr=0x%x\n", chip);
+	bus = tegra_i2c_get_bus(i2c_get_bus_num());
+	if (!bus)
+		return 1;
 	reg = 0;
-	rc = i2c_write_data(chip, &reg, 1);
+	rc = i2c_write_data(bus, chip, &reg, 1);
 	if (rc) {
 		debug("Error probing 0x%x.\n", chip);
 		return 1;
@@ -524,11 +560,15 @@ static int i2c_addr_ok(const uint addr, const int alen)
 /* Read bytes */
 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
+	struct i2c_bus *bus;
 	uint offset;
 	int i;
 
 	debug("i2c_read: chip=0x%x, addr=0x%x, len=0x%x\n",
 				chip, addr, len);
+	bus = tegra_i2c_get_bus(i2c_bus_num);
+	if (!bus)
+		return 1;
 	if (!i2c_addr_ok(addr, alen)) {
 		debug("i2c_read: Bad address %x.%d.\n", addr, alen);
 		return 1;
@@ -540,13 +580,13 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 				data[alen - i - 1] =
 					(addr + offset) >> (8 * i);
 			}
-			if (i2c_write_data(chip, data, alen)) {
+			if (i2c_write_data(bus, chip, data, alen)) {
 				debug("i2c_read: error sending (0x%x)\n",
 					addr);
 				return 1;
 			}
 		}
-		if (i2c_read_data(chip, buffer + offset, 1)) {
+		if (i2c_read_data(bus, chip, buffer + offset, 1)) {
 			debug("i2c_read: error reading (0x%x)\n", addr);
 			return 1;
 		}
@@ -558,11 +598,15 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 /* Write bytes */
 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 {
+	struct i2c_bus *bus;
 	uint offset;
 	int i;
 
 	debug("i2c_write: chip=0x%x, addr=0x%x, len=0x%x\n",
 				chip, addr, len);
+	bus = tegra_i2c_get_bus(i2c_bus_num);
+	if (!bus)
+		return 1;
 	if (!i2c_addr_ok(addr, alen)) {
 		debug("i2c_write: Bad address %x.%d.\n", addr, alen);
 		return 1;
@@ -572,7 +616,7 @@ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 		for (i = 0; i < alen; i++)
 			data[alen - i - 1] = (addr + offset) >> (8 * i);
 		data[alen] = buffer[offset];
-		if (i2c_write_data(chip, data, alen + 1)) {
+		if (i2c_write_data(bus, chip, data, alen + 1)) {
 			debug("i2c_write: error sending (0x%x)\n", addr);
 			return 1;
 		}