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u-boot/drivers/serial/serial_intel_mid.c
Simon Glass d30c7209df serial: Update NS16550_t and struct NS16550
Typedefs should not be used in U-Boot and structs should be lower case.
Update the code to use struct ns16550 consistently.

Put a header guard on the file while we are here.

Signed-off-by: Simon Glass <sjg@chromium.org>

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2021-01-05 12:24:40 -07:00

67 lines
1.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2017 Intel Corporation
*/
#include <common.h>
#include <dm.h>
#include <ns16550.h>
#include <serial.h>
/*
* The UART clock is calculated as
*
* UART clock = XTAL * UART_MUL / UART_DIV
*
* The baudrate is calculated as
*
* baud rate = UART clock / UART_PS / DLAB
*/
#define UART_PS 0x30
#define UART_MUL 0x34
#define UART_DIV 0x38
static void mid_writel(struct ns16550_plat *plat, int offset, int value)
{
unsigned char *addr;
offset *= 1 << plat->reg_shift;
addr = (unsigned char *)plat->base + offset;
writel(value, addr + plat->reg_offset);
}
static int mid_serial_probe(struct udevice *dev)
{
struct ns16550_plat *plat = dev_get_plat(dev);
/*
* Initialize fractional divider correctly for Intel Edison
* platform.
*
* For backward compatibility we have to set initial DLAB value
* to 16 and speed to 115200 baud, where initial frequency is
* 29491200Hz, and XTAL frequency is 38.4MHz.
*/
mid_writel(plat, UART_MUL, 96);
mid_writel(plat, UART_DIV, 125);
mid_writel(plat, UART_PS, 16);
return ns16550_serial_probe(dev);
}
static const struct udevice_id mid_serial_ids[] = {
{ .compatible = "intel,mid-uart" },
{}
};
U_BOOT_DRIVER(serial_intel_mid) = {
.name = "serial_intel_mid",
.id = UCLASS_SERIAL,
.of_match = mid_serial_ids,
.of_to_plat = ns16550_serial_of_to_plat,
.plat_auto = sizeof(struct ns16550_plat),
.priv_auto = sizeof(struct ns16550),
.probe = mid_serial_probe,
.ops = &ns16550_serial_ops,
};