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
18static const struct mfd_cell at91_usart_spi_subdev =
19	MFD_CELL_NAME("at91_usart_spi");
20
21static const struct mfd_cell at91_usart_serial_subdev =
22	MFD_CELL_NAME("atmel_usart_serial");
23
24static 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
48static const struct of_device_id at91_usart_mode_of_match[] = {
49	{ .compatible = "atmel,at91rm9200-usart" },
50	{ .compatible = "atmel,at91sam9260-usart" },
51	{ /* sentinel */ }
52};
53
54MODULE_DEVICE_TABLE(of, at91_usart_mode_of_match);
55
56static 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
64module_platform_driver(at91_usart_mfd);
65
66MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
67MODULE_DESCRIPTION("AT91 USART MFD driver");
68MODULE_LICENSE("GPL v2");
69