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path: root/drivers/tty/serial/8250/8250_tegra.c
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Diffstat (limited to 'drivers/tty/serial/8250/8250_tegra.c')
-rw-r--r--drivers/tty/serial/8250/8250_tegra.c200
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_tegra.c b/drivers/tty/serial/8250/8250_tegra.c
new file mode 100644
index 000000000..b6694ddfc
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_tegra.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Serial Port driver for Tegra devices
+ *
+ * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
+ */
+
+#include <linux/acpi.h>
+#include <linux/clk.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "8250.h"
+
+struct tegra_uart {
+ struct clk *clk;
+ struct reset_control *rst;
+ int line;
+};
+
+static void tegra_uart_handle_break(struct uart_port *p)
+{
+ unsigned int status, tmout = 10000;
+
+ do {
+ status = p->serial_in(p, UART_LSR);
+ if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
+ status = p->serial_in(p, UART_RX);
+ else
+ break;
+ if (--tmout == 0)
+ break;
+ udelay(1);
+ } while (1);
+}
+
+static int tegra_uart_probe(struct platform_device *pdev)
+{
+ struct uart_8250_port port8250;
+ struct tegra_uart *uart;
+ struct uart_port *port;
+ struct resource *res;
+ int ret;
+
+ uart = devm_kzalloc(&pdev->dev, sizeof(*uart), GFP_KERNEL);
+ if (!uart)
+ return -ENOMEM;
+
+ memset(&port8250, 0, sizeof(port8250));
+
+ port = &port8250.port;
+ spin_lock_init(&port->lock);
+
+ port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
+ UPF_FIXED_TYPE;
+ port->iotype = UPIO_MEM32;
+ port->regshift = 2;
+ port->type = PORT_TEGRA;
+ port->irqflags |= IRQF_SHARED;
+ port->dev = &pdev->dev;
+ port->handle_break = tegra_uart_handle_break;
+
+ ret = of_alias_get_id(pdev->dev.of_node, "serial");
+ if (ret >= 0)
+ port->line = ret;
+
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ return ret;
+
+ port->irq = ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ port->membase = devm_ioremap(&pdev->dev, res->start,
+ resource_size(res));
+ if (!port->membase)
+ return -ENOMEM;
+
+ port->mapbase = res->start;
+ port->mapsize = resource_size(res);
+
+ uart->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+ if (IS_ERR(uart->rst))
+ return PTR_ERR(uart->rst);
+
+ if (device_property_read_u32(&pdev->dev, "clock-frequency",
+ &port->uartclk)) {
+ uart->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(uart->clk)) {
+ dev_err(&pdev->dev, "failed to get clock!\n");
+ return -ENODEV;
+ }
+
+ ret = clk_prepare_enable(uart->clk);
+ if (ret < 0)
+ return ret;
+
+ port->uartclk = clk_get_rate(uart->clk);
+ }
+
+ ret = reset_control_deassert(uart->rst);
+ if (ret)
+ goto err_clkdisable;
+
+ ret = serial8250_register_8250_port(&port8250);
+ if (ret < 0)
+ goto err_ctrl_assert;
+
+ platform_set_drvdata(pdev, uart);
+ uart->line = ret;
+
+ return 0;
+
+err_ctrl_assert:
+ reset_control_assert(uart->rst);
+err_clkdisable:
+ clk_disable_unprepare(uart->clk);
+
+ return ret;
+}
+
+static int tegra_uart_remove(struct platform_device *pdev)
+{
+ struct tegra_uart *uart = platform_get_drvdata(pdev);
+
+ serial8250_unregister_port(uart->line);
+ reset_control_assert(uart->rst);
+ clk_disable_unprepare(uart->clk);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_uart_suspend(struct device *dev)
+{
+ struct tegra_uart *uart = dev_get_drvdata(dev);
+ struct uart_8250_port *port8250 = serial8250_get_port(uart->line);
+ struct uart_port *port = &port8250->port;
+
+ serial8250_suspend_port(uart->line);
+
+ if (!uart_console(port) || console_suspend_enabled)
+ clk_disable_unprepare(uart->clk);
+
+ return 0;
+}
+
+static int tegra_uart_resume(struct device *dev)
+{
+ struct tegra_uart *uart = dev_get_drvdata(dev);
+ struct uart_8250_port *port8250 = serial8250_get_port(uart->line);
+ struct uart_port *port = &port8250->port;
+
+ if (!uart_console(port) || console_suspend_enabled)
+ clk_prepare_enable(uart->clk);
+
+ serial8250_resume_port(uart->line);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(tegra_uart_pm_ops, tegra_uart_suspend,
+ tegra_uart_resume);
+
+static const struct of_device_id tegra_uart_of_match[] = {
+ { .compatible = "nvidia,tegra20-uart", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
+
+static const struct acpi_device_id tegra_uart_acpi_match[] = {
+ { "NVDA0100", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(acpi, tegra_uart_acpi_match);
+
+static struct platform_driver tegra_uart_driver = {
+ .driver = {
+ .name = "tegra-uart",
+ .pm = &tegra_uart_pm_ops,
+ .of_match_table = tegra_uart_of_match,
+ .acpi_match_table = ACPI_PTR(tegra_uart_acpi_match),
+ },
+ .probe = tegra_uart_probe,
+ .remove = tegra_uart_remove,
+};
+
+module_platform_driver(tegra_uart_driver);
+
+MODULE_AUTHOR("Jeff Brasen <jbrasen@nvidia.com>");
+MODULE_DESCRIPTION("NVIDIA Tegra 8250 Driver");
+MODULE_LICENSE("GPL v2");