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 .name = "at91_usart_spi",
20 .of_compatible = "microchip,at91sam9g45-usart-spi",
21 };
22
23 static const struct mfd_cell at91_usart_serial_subdev = {
24 .name = "atmel_usart_serial",
25 .of_compatible = "atmel,at91rm9200-usart-serial",
26 };
27
at91_usart_mode_probe(struct platform_device * pdev)28 static int at91_usart_mode_probe(struct platform_device *pdev)
29 {
30 const 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");
73