// SPDX-License-Identifier: GPL-2.0+ /* * Serial Port driver for Tegra devices * * Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved. */ #include #include #include #include #include #include #include #include #include #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 = tegra_uart_remove, }; module_platform_driver(tegra_uart_driver); MODULE_AUTHOR("Jeff Brasen "); MODULE_DESCRIPTION("NVIDIA Tegra 8250 Driver"); MODULE_LICENSE("GPL v2");