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
at91_usart_mode_probe(struct platform_device * pdev)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");
69