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// 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/of.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;
while (1) {
status = p->serial_in(p, UART_LSR);
if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)))
break;
p->serial_in(p, UART_RX);
if (--tmout == 0)
break;
udelay(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_BOOT_AUTOCONF | UPF_FIXED_PORT | UPF_FIXED_TYPE;
port->type = PORT_TEGRA;
port->dev = &pdev->dev;
port->handle_break = tegra_uart_handle_break;
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);
ret = uart_read_port_properties(port);
if (ret)
return ret;
port->iotype = UPIO_MEM32;
port->regshift = 2;
uart->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
if (IS_ERR(uart->rst))
return PTR_ERR(uart->rst);
if (!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 void 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);
}
#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[] __maybe_unused = {
{ "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_new = 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");
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