serial: tegra: set maximum num of uart ports to 8

Set maximum number of UART ports to 8 as older chips have 5 ports and
Tergra186 and later chips will have 8 ports. Add this info to chip
data. Read device tree compatible of this driver and register uart
driver with max ports of matching chip data.

Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com>
Signed-off-by: Krishna Yarlagadda <kyarlagadda@nvidia.com>
Link: https://lore.kernel.org/r/1567572187-29820-8-git-send-email-kyarlagadda@nvidia.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

@@ -62,7 +62,7 @@
 #define TEGRA_UART_TX_TRIG_4B			0x20
 #define TEGRA_UART_TX_TRIG_1B			0x30
 
-#define TEGRA_UART_MAXIMUM			5
+#define TEGRA_UART_MAXIMUM			8
 
 /* Default UART setting when started: 115200 no parity, stop, 8 data bits */
 #define TEGRA_UART_DEFAULT_BAUD			115200
@@ -87,6 +87,7 @@ struct tegra_uart_chip_data {
 	bool	allow_txfifo_reset_fifo_mode;
 	bool	support_clk_src_div;
 	bool	fifo_mode_enable_status;
+	int	uart_max_port;
 };
 
 struct tegra_uart_port {
@@ -1322,20 +1323,23 @@ static struct tegra_uart_chip_data tegra20_uart_chip_data = {
 	.allow_txfifo_reset_fifo_mode	= true,
 	.support_clk_src_div		= false,
 	.fifo_mode_enable_status	= false,
+	.uart_max_port			= 5,
 };
 
 static struct tegra_uart_chip_data tegra30_uart_chip_data = {
 	.tx_fifo_full_status		= true,
 	.allow_txfifo_reset_fifo_mode	= false,
 	.support_clk_src_div		= true,
 	.fifo_mode_enable_status	= false,
+	.uart_max_port			= 5,
 };
 
 static struct tegra_uart_chip_data tegra186_uart_chip_data = {
 	.tx_fifo_full_status		= true,
 	.allow_txfifo_reset_fifo_mode	= false,
 	.support_clk_src_div		= true,
 	.fifo_mode_enable_status	= true,
+	.uart_max_port			= 8,
 };
 
 static const struct of_device_id tegra_uart_of_match[] = {
@@ -1468,11 +1472,22 @@ static struct platform_driver tegra_uart_platform_driver = {
 static int __init tegra_uart_init(void)
 {
 	int ret;
+	struct device_node *node;
+	const struct of_device_id *match = NULL;
+	const struct tegra_uart_chip_data *cdata = NULL;
+
+	node = of_find_matching_node(NULL, tegra_uart_of_match);
+	if (node)
+		match = of_match_node(tegra_uart_of_match, node);
+	if (match)
+		cdata = match->data;
+	if (cdata)
+		tegra_uart_driver.nr = cdata->uart_max_port;
 
 	ret = uart_register_driver(&tegra_uart_driver);
 	if (ret < 0) {
 		pr_err("Could not register %s driver\n",
-			tegra_uart_driver.driver_name);
+		       tegra_uart_driver.driver_name);
 		return ret;
 	}