1 files changed, 110 insertions, 34 deletions

diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
index 12d03e678295..0609582a62f7 100644
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -13,10 +13,12 @@
  */
 
 #include <linux/clk.h>
+#include <linux/console.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 
 #include "8250.h"
 
@@ -44,7 +46,7 @@ struct bcm2835aux_data {
 	u32 cntl;
 };
 
-static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up)
+static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up, bool toggle_ier)
 {
 	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
 		struct bcm2835aux_data *data = dev_get_drvdata(up->port.dev);
@@ -63,7 +65,7 @@ static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up)
 		serial8250_out_MCR(up, UART_MCR_RTS);
 }
 
-static void bcm2835aux_rs485_stop_tx(struct uart_8250_port *up)
+static void bcm2835aux_rs485_stop_tx(struct uart_8250_port *up, bool toggle_ier)
 {
 	if (up->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
 		serial8250_out_MCR(up, 0);
@@ -80,9 +82,11 @@ static void bcm2835aux_rs485_stop_tx(struct uart_8250_port *up)
 
 static int bcm2835aux_serial_probe(struct platform_device *pdev)
 {
+	const struct software_node *bcm2835_swnode;
 	struct uart_8250_port up = { };
 	struct bcm2835aux_data *data;
 	struct resource *res;
+	unsigned int uartclk;
 	int ret;
 
 	/* allocate the custom structure */
@@ -93,13 +97,10 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	/* initialize data */
 	up.capabilities = UART_CAP_FIFO | UART_CAP_MINI;
 	up.port.dev = &pdev->dev;
-	up.port.regshift = 2;
 	up.port.type = PORT_16550;
-	up.port.iotype = UPIO_MEM;
-	up.port.fifosize = 8;
-	up.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE |
-			UPF_SKIP_TEST | UPF_IOREMAP;
+	up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SKIP_TEST | UPF_IOREMAP;
 	up.port.rs485_config = serial8250_em485_config;
+	up.port.rs485_supported = serial8250_em485_supported;
 	up.rs485_start_tx = bcm2835aux_rs485_start_tx;
 	up.rs485_stop_tx = bcm2835aux_rs485_stop_tx;
 
@@ -109,19 +110,9 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, data);
 
 	/* get the clock - this also enables the HW */
-	data->clk = devm_clk_get(&pdev->dev, NULL);
-	ret = PTR_ERR_OR_ZERO(data->clk);
-	if (ret) {
-		if (ret != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "could not get clk: %d\n", ret);
-		return ret;
-	}
-
-	/* get the interrupt */
-	ret = platform_get_irq(pdev, 0);
-	if (ret < 0)
-		return ret;
-	up.port.irq = ret;
+	data->clk = devm_clk_get_optional(&pdev->dev, NULL);
+	if (IS_ERR(data->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk), "could not get clk\n");
 
 	/* map the main registers */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -129,35 +120,46 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "memory resource not found");
 		return -EINVAL;
 	}
+
 	up.port.mapbase = res->start;
 	up.port.mapsize = resource_size(res);
 
-	/* Check for a fixed line number */
-	ret = of_alias_get_id(pdev->dev.of_node, "serial");
-	if (ret >= 0)
-		up.port.line = ret;
+	bcm2835_swnode = device_get_match_data(&pdev->dev);
+	if (bcm2835_swnode) {
+		ret = device_add_software_node(&pdev->dev, bcm2835_swnode);
+		if (ret)
+			return ret;
+	}
+
+	ret = uart_read_port_properties(&up.port);
+	if (ret)
+		goto rm_swnode;
+
+	up.port.regshift = 2;
+	up.port.fifosize = 8;
 
 	/* enable the clock as a last step */
 	ret = clk_prepare_enable(data->clk);
 	if (ret) {
-		dev_err(&pdev->dev, "unable to enable uart clock - %d\n",
-			ret);
-		return ret;
+		dev_err_probe(&pdev->dev, ret, "unable to enable uart clock\n");
+		goto rm_swnode;
 	}
 
+	uartclk = clk_get_rate(data->clk);
+	if (uartclk)
+		up.port.uartclk = uartclk;
+
 	/* the HW-clock divider for bcm2835aux is 8,
 	 * but 8250 expects a divider of 16,
 	 * so we have to multiply the actual clock by 2
 	 * to get identical baudrates.
 	 */
-	up.port.uartclk = clk_get_rate(data->clk) * 2;
+	up.port.uartclk *= 2;
 
 	/* register the port */
 	ret = serial8250_register_8250_port(&up);
 	if (ret < 0) {
-		if (ret != -EPROBE_DEFER)
-			dev_err(&pdev->dev,
-				"unable to register 8250 port - %d\n", ret);
+		dev_err_probe(&pdev->dev, ret, "unable to register 8250 port\n");
 		goto dis_clk;
 	}
 	data->line = ret;
@@ -166,29 +168,103 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 
 dis_clk:
 	clk_disable_unprepare(data->clk);
+rm_swnode:
+	device_remove_software_node(&pdev->dev);
 	return ret;
 }
 
-static int bcm2835aux_serial_remove(struct platform_device *pdev)
+static void bcm2835aux_serial_remove(struct platform_device *pdev)
 {
 	struct bcm2835aux_data *data = platform_get_drvdata(pdev);
 
 	serial8250_unregister_port(data->line);
 	clk_disable_unprepare(data->clk);
-
-	return 0;
+	device_remove_software_node(&pdev->dev);
 }
 
+/*
+ * Some UEFI implementations (e.g. tianocore/edk2 for the Raspberry Pi)
+ * describe the miniuart with a base address that encompasses the auxiliary
+ * registers shared between the miniuart and spi.
+ *
+ * This is due to historical reasons, see discussion here:
+ * https://edk2.groups.io/g/devel/topic/87501357#84349
+ *
+ * We need to add the offset between the miniuart and auxiliary registers
+ * to get the real miniuart base address.
+ */
+static const struct property_entry bcm2835_acpi_properties[] = {
+	PROPERTY_ENTRY_U32("reg-offset", 0x40),
+	{ }
+};
+
+static const struct software_node bcm2835_acpi_node = {
+	.properties = bcm2835_acpi_properties,
+};
+
 static const struct of_device_id bcm2835aux_serial_match[] = {
 	{ .compatible = "brcm,bcm2835-aux-uart" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, bcm2835aux_serial_match);
 
+static const struct acpi_device_id bcm2835aux_serial_acpi_match[] = {
+	{ "BCM2836", (kernel_ulong_t)&bcm2835_acpi_node },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match);
+
+static bool bcm2835aux_can_disable_clock(struct device *dev)
+{
+	struct bcm2835aux_data *data = dev_get_drvdata(dev);
+	struct uart_8250_port *up = serial8250_get_port(data->line);
+
+	if (device_may_wakeup(dev))
+		return false;
+
+	if (uart_console(&up->port) && !console_suspend_enabled)
+		return false;
+
+	return true;
+}
+
+static int bcm2835aux_suspend(struct device *dev)
+{
+	struct bcm2835aux_data *data = dev_get_drvdata(dev);
+
+	serial8250_suspend_port(data->line);
+
+	if (!bcm2835aux_can_disable_clock(dev))
+		return 0;
+
+	clk_disable_unprepare(data->clk);
+	return 0;
+}
+
+static int bcm2835aux_resume(struct device *dev)
+{
+	struct bcm2835aux_data *data = dev_get_drvdata(dev);
+	int ret;
+
+	if (bcm2835aux_can_disable_clock(dev)) {
+		ret = clk_prepare_enable(data->clk);
+		if (ret)
+			return ret;
+	}
+
+	serial8250_resume_port(data->line);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(bcm2835aux_dev_pm_ops, bcm2835aux_suspend, bcm2835aux_resume);
+
 static struct platform_driver bcm2835aux_serial_driver = {
 	.driver = {
 		.name = "bcm2835-aux-uart",
 		.of_match_table = bcm2835aux_serial_match,
+		.acpi_match_table = bcm2835aux_serial_acpi_match,
+		.pm = pm_ptr(&bcm2835aux_dev_pm_ops),
 	},
 	.probe  = bcm2835aux_serial_probe,
 	.remove = bcm2835aux_serial_remove,