drivers/mfd/at91-usart.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Driver for AT91 USART
0004  *
0005  * Copyright (C) 2018 Microchip Technology
0006  *
0007  * Author: Radu Pirea <radu.pirea@microchip.com>
0008  *
0009  */
0010
0011 #include <dt-bindings/mfd/at91-usart.h>
0012
0013 #include <linux/module.h>
0014 #include <linux/mfd/core.h>
0015 #include <linux/of.h>
0016 #include <linux/property.h>
0017
0018 static const struct mfd_cell at91_usart_spi_subdev =
0019     MFD_CELL_NAME("at91_usart_spi");
0020
0021 static const struct mfd_cell at91_usart_serial_subdev =
0022     MFD_CELL_NAME("atmel_usart_serial");
0023
0024 static int at91_usart_mode_probe(struct platform_device *pdev)
0025 {
0026     const struct mfd_cell *cell;
0027     u32 opmode = AT91_USART_MODE_SERIAL;
0028
0029     device_property_read_u32(&pdev->dev, "atmel,usart-mode", &opmode);
0030
0031     switch (opmode) {
0032     case AT91_USART_MODE_SPI:
0033         cell = &at91_usart_spi_subdev;
0034         break;
0035     case AT91_USART_MODE_SERIAL:
0036         cell = &at91_usart_serial_subdev;
0037         break;
0038     default:
0039         dev_err(&pdev->dev, "atmel,usart-mode has an invalid value %u\n",
0040             opmode);
0041         return -EINVAL;
0042     }
0043
0044     return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, cell, 1,
0045                   NULL, 0, NULL);
0046 }
0047
0048 static const struct of_device_id at91_usart_mode_of_match[] = {
0049     { .compatible = "atmel,at91rm9200-usart" },
0050     { .compatible = "atmel,at91sam9260-usart" },
0051     { /* sentinel */ }
0052 };
0053
0054 MODULE_DEVICE_TABLE(of, at91_usart_mode_of_match);
0055
0056 static struct platform_driver at91_usart_mfd = {
0057     .probe  = at91_usart_mode_probe,
0058     .driver = {
0059         .name       = "at91_usart_mode",
0060         .of_match_table = at91_usart_mode_of_match,
0061     },
0062 };
0063
0064 module_platform_driver(at91_usart_mfd);
0065
0066 MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
0067 MODULE_DESCRIPTION("AT91 USART MFD driver");
0068 MODULE_LICENSE("GPL v2");