1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Copyright (c) 2018 Alexander Graf <agraf@suse.de> 4 */ 5 6#include <common.h> 7#include <dm.h> 8#include <asm/gpio.h> 9#include <dm/pinctrl.h> 10#include <dm/platform_data/serial_pl01x.h> 11#include <serial.h> 12#include "serial_pl01x_internal.h" 13 14/* 15 * Check if this serial device is muxed 16 * 17 * The serial device will only work properly if it has been muxed to the serial 18 * pins by firmware. Check whether that happened here. 19 * 20 * Return: true if serial device is muxed, false if not 21 */ 22static bool bcm283x_is_serial_muxed(void) 23{ 24 int serial_gpio = 15; 25 struct udevice *dev; 26 27 if (uclass_first_device_err(UCLASS_PINCTRL, &dev)) 28 return false; 29 30 if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT0) 31 return false; 32 33 return true; 34} 35 36static int bcm283x_pl011_serial_probe(struct udevice *dev) 37{ 38 struct pl01x_serial_plat *plat = dev_get_plat(dev); 39 int ret; 40 41 /* Don't spawn the device if it's not muxed */ 42 if (!bcm283x_is_serial_muxed()) 43 return -ENODEV; 44 45 /* 46 * Read the ofdata here rather than in an of_to_plat() method 47 * since we need the soc simple-bus to be probed so that the 'ranges' 48 * property is used. 49 */ 50 ret = pl01x_serial_of_to_plat(dev); 51 if (ret) 52 return ret; 53 54 /* 55 * TODO: Reinitialization doesn't always work for now, just skip 56 * init always - we know we're already initialized 57 */ 58 plat->skip_init = true; 59 60 return pl01x_serial_probe(dev); 61} 62 63static int bcm283x_pl011_serial_setbrg(struct udevice *dev, int baudrate) 64{ 65 int r; 66 67 r = pl01x_serial_setbrg(dev, baudrate); 68 69 /* 70 * We may have been muxed to a bogus line before. Drain the RX 71 * queue so we start at a clean slate. 72 */ 73 while (pl01x_serial_getc(dev) != -EAGAIN) ; 74 75 return r; 76} 77 78static const struct dm_serial_ops bcm283x_pl011_serial_ops = { 79 .putc = pl01x_serial_putc, 80 .pending = pl01x_serial_pending, 81 .getc = pl01x_serial_getc, 82 .setbrg = bcm283x_pl011_serial_setbrg, 83}; 84 85static const struct udevice_id bcm283x_pl011_serial_id[] = { 86 {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011}, 87 {} 88}; 89 90U_BOOT_DRIVER(bcm283x_pl011_uart) = { 91 .name = "bcm283x_pl011", 92 .id = UCLASS_SERIAL, 93 .of_match = of_match_ptr(bcm283x_pl011_serial_id), 94 .probe = bcm283x_pl011_serial_probe, 95 .plat_auto = sizeof(struct pl01x_serial_plat), 96 .ops = &bcm283x_pl011_serial_ops, 97#if !CONFIG_IS_ENABLED(OF_CONTROL) || IS_ENABLED(CONFIG_OF_BOARD) 98 .flags = DM_FLAG_PRE_RELOC, 99#endif 100 .priv_auto = sizeof(struct pl01x_priv), 101}; 102