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// 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);
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