drivers/mfd/at91-usart.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Driver for AT91 USART
   4  *
   5  * Copyright (C) 2018 Microchip Technology
   6  *
   7  * Author: Radu Pirea <radu.pirea@microchip.com>
   8  *
   9  */
  10
  11 #include <dt-bindings/mfd/at91-usart.h>
  12
  13 #include <linux/module.h>
  14 #include <linux/mfd/core.h>
  15 #include <linux/of.h>
  16 #include <linux/property.h>
  17
  18 static struct mfd_cell at91_usart_spi_subdev = {
  19                 .name = "at91_usart_spi",
  20                 .of_compatible = "microchip,at91sam9g45-usart-spi",
  21         };
  22
  23 static struct mfd_cell at91_usart_serial_subdev = {
  24                 .name = "atmel_usart_serial",
  25                 .of_compatible = "atmel,at91rm9200-usart-serial",
  26         };
  27
  28 static int at91_usart_mode_probe(struct platform_device *pdev)
  29 {
  30         struct mfd_cell cell;
  31         u32 opmode = AT91_USART_MODE_SERIAL;
  32
  33         device_property_read_u32(&pdev->dev, "atmel,usart-mode", &opmode);
  34
  35         switch (opmode) {
  36         case AT91_USART_MODE_SPI:
  37                 cell = at91_usart_spi_subdev;
  38                 break;
  39         case AT91_USART_MODE_SERIAL:
  40                 cell = at91_usart_serial_subdev;
  41                 break;
  42         default:
  43                 dev_err(&pdev->dev, "atmel,usart-mode has an invalid value %u\n",
  44                         opmode);
  45                 return -EINVAL;
  46         }
  47
  48         return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, &cell, 1,
  49                               NULL, 0, NULL);
  50 }
  51
  52 static const struct of_device_id at91_usart_mode_of_match[] = {
  53         { .compatible = "atmel,at91rm9200-usart" },
  54         { .compatible = "atmel,at91sam9260-usart" },
  55         { /* sentinel */ }
  56 };
  57
  58 MODULE_DEVICE_TABLE(of, at91_usart_mode_of_match);
  59
  60 static struct platform_driver at91_usart_mfd = {
  61         .probe  = at91_usart_mode_probe,
  62         .driver = {
  63                 .name           = "at91_usart_mode",
  64                 .of_match_table = at91_usart_mode_of_match,
  65         },
  66 };
  67
  68 module_platform_driver(at91_usart_mfd);
  69
  70 MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
  71 MODULE_DESCRIPTION("AT91 USART MFD driver");
  72 MODULE_LICENSE("GPL v2");