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 const struct mfd_cell at91_usart_spi_subdev =
  19         MFD_CELL_NAME("at91_usart_spi");
  20
  21 static const struct mfd_cell at91_usart_serial_subdev =
  22         MFD_CELL_NAME("atmel_usart_serial");
  23
  24 static int at91_usart_mode_probe(struct platform_device *pdev)
  25 {
  26         const struct mfd_cell *cell;
  27         u32 opmode = AT91_USART_MODE_SERIAL;
  28
  29         device_property_read_u32(&pdev->dev, "atmel,usart-mode", &opmode);
  30
  31         switch (opmode) {
  32         case AT91_USART_MODE_SPI:
  33                 cell = &at91_usart_spi_subdev;
  34                 break;
  35         case AT91_USART_MODE_SERIAL:
  36                 cell = &at91_usart_serial_subdev;
  37                 break;
  38         default:
  39                 dev_err(&pdev->dev, "atmel,usart-mode has an invalid value %u\n",
  40                         opmode);
  41                 return -EINVAL;
  42         }
  43
  44         return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, cell, 1,
  45                               NULL, 0, NULL);
  46 }
  47
  48 static const struct of_device_id at91_usart_mode_of_match[] = {
  49         { .compatible = "atmel,at91rm9200-usart" },
  50         { .compatible = "atmel,at91sam9260-usart" },
  51         { /* sentinel */ }
  52 };
  53
  54 MODULE_DEVICE_TABLE(of, at91_usart_mode_of_match);
  55
  56 static struct platform_driver at91_usart_mfd = {
  57         .probe  = at91_usart_mode_probe,
  58         .driver = {
  59                 .name           = "at91_usart_mode",
  60                 .of_match_table = at91_usart_mode_of_match,
  61         },
  62 };
  63
  64 module_platform_driver(at91_usart_mfd);
  65
  66 MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
  67 MODULE_DESCRIPTION("AT91 USART MFD driver");
  68 MODULE_LICENSE("GPL v2");