drivers/serial/serial_bcm283x_pl011.c

   1 /*
   2  * Copyright (c) 2018 Alexander Graf <agraf@suse.de>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <asm/gpio.h>
  10 #include <dm/pinctrl.h>
  11 #include <dm/platform_data/serial_pl01x.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  */
  22 static bool bcm283x_is_serial_muxed(void)
  23 {
  24         int serial_gpio = 15;
  25         struct udevice *dev;
  26
  27         if (uclass_first_device(UCLASS_PINCTRL, &dev) || !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
  36 static int bcm283x_pl011_serial_ofdata_to_platdata(struct udevice *dev)
  37 {
  38         struct pl01x_serial_platdata *plat = dev_get_platdata(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         ret = pl01x_serial_ofdata_to_platdata(dev);
  46         if (ret)
  47                 return ret;
  48
  49         /*
  50          * TODO: Reinitialization doesn't always work for now, just skip
  51          *       init always - we know we're already initialized
  52          */
  53         plat->skip_init = true;
  54
  55         return 0;
  56 }
  57
  58 static const struct udevice_id bcm283x_pl011_serial_id[] = {
  59         {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
  60         {}
  61 };
  62
  63 U_BOOT_DRIVER(bcm283x_pl011_uart) = {
  64         .name   = "bcm283x_pl011",
  65         .id     = UCLASS_SERIAL,
  66         .of_match = of_match_ptr(bcm283x_pl011_serial_id),
  67         .ofdata_to_platdata = of_match_ptr(bcm283x_pl011_serial_ofdata_to_platdata),
  68         .platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
  69         .probe  = pl01x_serial_probe,
  70         .ops    = &pl01x_serial_ops,
  71         .flags  = DM_FLAG_PRE_RELOC,
  72         .priv_auto_alloc_size = sizeof(struct pl01x_priv),
  73 };