diff options
Diffstat (limited to 'drivers/serial/serial_lpuart32.c')
| -rw-r--r-- | drivers/serial/serial_lpuart32.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/serial/serial_lpuart32.c b/drivers/serial/serial_lpuart32.c new file mode 100644 index 0000000000..09d4b620be --- /dev/null +++ b/drivers/serial/serial_lpuart32.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2023 Pengutronix + */ + +#include <common.h> +#include <driver.h> +#include <init.h> +#include <malloc.h> +#include <notifier.h> +#include <io.h> +#include <of.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <serial/lpuart32.h> + +struct lpuart32_devtype_data { + unsigned int reg_offs; +}; + +struct lpuart32 { + struct console_device cdev; + int baudrate; + int dte_mode; + struct notifier_block notify; + struct resource *io; + void __iomem *base; + struct clk *clk; +}; + +static struct lpuart32 *cdev_to_lpuart32(struct console_device *cdev) +{ + return container_of(cdev, struct lpuart32, cdev); +} + +static void lpuart32_enable(struct lpuart32 *lpuart32) +{ + writel(LPUART32_UARTCTRL_TE | LPUART32_UARTCTRL_RE, + lpuart32->base + LPUART32_UARTCTRL); +} + +static void lpuart32_disable(struct lpuart32 *lpuart32) +{ + writel(0, lpuart32->base + LPUART32_UARTCTRL); +} + +/* Test whether a character is in the RX buffer */ +static int lpuart32_serial_tstc(struct console_device *cdev) +{ + struct lpuart32 *lpuart32 = cdev_to_lpuart32(cdev); + + if (readl(lpuart32->base + LPUART32_UARTSTAT) & LPUART32_UARTSTAT_OR) + writel(LPUART32_UARTSTAT_OR, lpuart32->base + LPUART32_UARTSTAT); + + return readl(lpuart32->base + LPUART32_UARTSTAT) & LPUART32_UARTSTAT_RDRF; +} + +static int lpuart32_serial_setbaudrate(struct console_device *cdev, + int baudrate) +{ + struct lpuart32 *lpuart32 = cdev_to_lpuart32(cdev); + + lpuart32_disable(lpuart32); + + /* + * We treat baudrate of 0 as a request to disable UART + */ + if (baudrate) { + lpuart32_setbrg(lpuart32->base, clk_get_rate(lpuart32->clk), + baudrate); + lpuart32_enable(lpuart32); + } + + lpuart32->baudrate = baudrate; + + return 0; +} + +static int lpuart32_serial_getc(struct console_device *cdev) +{ + struct lpuart32 *lpuart32 = cdev_to_lpuart32(cdev); + + while (!lpuart32_serial_tstc(cdev)); + + return readl(lpuart32->base + LPUART32_UARTDATA) & 0xff; +} + +static void lpuart32_serial_putc(struct console_device *cdev, char c) +{ + struct lpuart32 *lpuart32 = cdev_to_lpuart32(cdev); + + lpuart32_putc(lpuart32->base, c); +} + +static void lpuart32_serial_flush(struct console_device *cdev) +{ +} + +static int lpuart32_serial_probe(struct device *dev) +{ + int ret; + struct console_device *cdev; + struct lpuart32 *lpuart32; + const char *devname; + struct lpuart32_devtype_data *devtype; + + ret = dev_get_drvdata(dev, (const void **)&devtype); + if (ret) + return ret; + + lpuart32 = xzalloc(sizeof(*lpuart32)); + cdev = &lpuart32->cdev; + dev->priv = lpuart32; + + lpuart32->io = dev_request_mem_resource(dev, 0); + if (IS_ERR(lpuart32->io)) { + ret = PTR_ERR(lpuart32->io); + goto err_free; + } + lpuart32->base = IOMEM(lpuart32->io->start) + devtype->reg_offs; + + lpuart32->clk = clk_get(dev, NULL); + if (IS_ERR(lpuart32->clk)) { + ret = PTR_ERR(lpuart32->clk); + dev_err(dev, "Failed to get UART clock %d\n", ret); + goto io_release; + } + + ret = clk_enable(lpuart32->clk); + if (ret) { + dev_err(dev, "Failed to enable UART clock %d\n", ret); + goto io_release; + } + + cdev->dev = dev; + cdev->tstc = lpuart32_serial_tstc; + cdev->putc = lpuart32_serial_putc; + cdev->getc = lpuart32_serial_getc; + cdev->flush = lpuart32_serial_flush; + cdev->setbrg = lpuart32_serial_setbaudrate; + + if (dev->of_node) { + devname = of_alias_get(dev->of_node); + if (devname) { + cdev->devname = xstrdup(devname); + cdev->devid = DEVICE_ID_SINGLE; + } + } + + cdev->linux_console_name = "ttyLP"; + cdev->linux_earlycon_name = "lpuart"; + cdev->phys_base = lpuart32->base; + + lpuart32_setup(lpuart32->base, clk_get_rate(lpuart32->clk)); + + ret = console_register(cdev); + if (!ret) + return 0; + + clk_put(lpuart32->clk); +io_release: + release_region(lpuart32->io); +err_free: + free(lpuart32); + + return ret; +} + +static struct lpuart32_devtype_data imx7ulp_data = { + .reg_offs = 0x10, +}; + +static struct of_device_id lpuart32_serial_dt_ids[] = { + { + .compatible = "fsl,imx7ulp-lpuart", + .data = &imx7ulp_data, + }, { + /* sentinel */ + } +}; +MODULE_DEVICE_TABLE(of, lpuart32_serial_dt_ids); + +static struct driver lpuart32_serial_driver = { + .name = "lpuart32-serial", + .probe = lpuart32_serial_probe, + .of_compatible = DRV_OF_COMPAT(lpuart32_serial_dt_ids), +}; +console_platform_driver(lpuart32_serial_driver); |