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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2016 Zodiac Inflight Innovation
* Author: Andrey Smirnov <andrew.smirnov@gmail.com>
*
* Based on analogous driver from U-Boot
*/
#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/lpuart.h>
struct lpuart {
struct console_device cdev;
int baudrate;
int dte_mode;
struct notifier_block notify;
struct resource *io;
void __iomem *base;
struct clk *clk;
};
static struct lpuart *cdev_to_lpuart(struct console_device *cdev)
{
return container_of(cdev, struct lpuart, cdev);
}
static struct lpuart *nb_to_lpuart(struct notifier_block *nb)
{
return container_of(nb, struct lpuart, notify);
}
static void lpuart_enable(struct lpuart *lpuart, bool on)
{
u8 ctrl;
ctrl = readb(lpuart->base + UARTCR2);
if (on)
ctrl |= UARTCR2_TE | UARTCR2_RE;
else
ctrl &= ~(UARTCR2_TE | UARTCR2_RE);
writeb(ctrl, lpuart->base + UARTCR2);
}
static int lpuart_serial_setbaudrate(struct console_device *cdev,
int baudrate)
{
struct lpuart *lpuart = cdev_to_lpuart(cdev);
lpuart_enable(lpuart, false);
/*
* We treat baudrate of 0 as a request to disable UART
*/
if (baudrate) {
lpuart_setbrg(lpuart->base, clk_get_rate(lpuart->clk),
baudrate);
lpuart_enable(lpuart, true);
}
lpuart->baudrate = baudrate;
return 0;
}
static int lpuart_serial_getc(struct console_device *cdev)
{
bool ready;
struct lpuart *lpuart = cdev_to_lpuart(cdev);
do {
const u8 sr1 = readb(lpuart->base + UARTSR1);
ready = !!(sr1 & (UARTSR1_OR | UARTSR1_RDRF));
} while (!ready);
return readb(lpuart->base + UARTDR);
}
static void lpuart_serial_putc(struct console_device *cdev, char c)
{
lpuart_putc(cdev_to_lpuart(cdev)->base, c);
}
/* Test whether a character is in the RX buffer */
static int lpuart_serial_tstc(struct console_device *cdev)
{
return !!readb(cdev_to_lpuart(cdev)->base + UARTRCFIFO);
}
static void lpuart_serial_flush(struct console_device *cdev)
{
bool tx_empty;
struct lpuart *lpuart = cdev_to_lpuart(cdev);
do {
const u8 sr1 = readb(lpuart->base + UARTSR1);
tx_empty = !!(sr1 & UARTSR1_TDRE);
} while (!tx_empty);
}
static int lpuart_clocksource_clock_change(struct notifier_block *nb,
unsigned long event, void *data)
{
struct lpuart *lpuart = nb_to_lpuart(nb);
return lpuart_serial_setbaudrate(&lpuart->cdev, lpuart->baudrate);
}
static int lpuart_serial_probe(struct device_d *dev)
{
int ret;
struct console_device *cdev;
struct lpuart *lpuart;
const char *devname;
lpuart = xzalloc(sizeof(*lpuart));
cdev = &lpuart->cdev;
dev->priv = lpuart;
lpuart->io = dev_request_mem_resource(dev, 0);
if (IS_ERR(lpuart->io)) {
ret = PTR_ERR(lpuart->io);
goto err_free;
}
lpuart->base = IOMEM(lpuart->io->start);
lpuart->clk = clk_get(dev, NULL);
if (IS_ERR(lpuart->clk)) {
ret = PTR_ERR(lpuart->clk);
dev_err(dev, "Failed to get UART clock %d\n", ret);
goto io_release;
}
ret = clk_enable(lpuart->clk);
if (ret) {
dev_err(dev, "Failed to enable UART clock %d\n", ret);
goto io_release;
}
cdev->dev = dev;
cdev->tstc = lpuart_serial_tstc;
cdev->putc = lpuart_serial_putc;
cdev->getc = lpuart_serial_getc;
cdev->flush = lpuart_serial_flush;
cdev->setbrg = lpuart_serial_setbaudrate;
if (dev->device_node) {
devname = of_alias_get(dev->device_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 = lpuart->base;
lpuart_setup(lpuart->base, clk_get_rate(lpuart->clk));
ret = console_register(cdev);
if (!ret) {
lpuart->notify.notifier_call = lpuart_clocksource_clock_change;
clock_register_client(&lpuart->notify);
return 0;
}
clk_put(lpuart->clk);
io_release:
release_region(lpuart->io);
err_free:
free(lpuart);
return ret;
}
static struct of_device_id lpuart_serial_dt_ids[] = {
{ .compatible = "fsl,vf610-lpuart" },
{}
};
static struct driver_d lpuart_serial_driver = {
.name = "lpuart-serial",
.probe = lpuart_serial_probe,
.of_compatible = DRV_OF_COMPAT(lpuart_serial_dt_ids),
};
console_platform_driver(lpuart_serial_driver);
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