diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_tegra.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_tegra.c | 201 |
1 files changed, 201 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..c424e2ae0 --- /dev/null +++ b/drivers/tty/serial/8250/8250_tegra.c @@ -0,0 +1,201 @@ +// 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; + + 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_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[] __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 <jbrasen@nvidia.com>"); +MODULE_DESCRIPTION("NVIDIA Tegra 8250 Driver"); +MODULE_LICENSE("GPL v2"); |