1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Siemens SIMATIC IPC driver for LEDs
4  *
5  * Copyright (c) Siemens AG, 2018-2021
6  *
7  * Authors:
8  *  Henning Schild <henning.schild@siemens.com>
9  *  Jan Kiszka <jan.kiszka@siemens.com>
10  *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
11  */
12 
13 #include <linux/ioport.h>
14 #include <linux/kernel.h>
15 #include <linux/leds.h>
16 #include <linux/module.h>
17 #include <linux/pci.h>
18 #include <linux/platform_data/x86/simatic-ipc-base.h>
19 #include <linux/platform_device.h>
20 #include <linux/sizes.h>
21 #include <linux/spinlock.h>
22 
23 #define SIMATIC_IPC_LED_PORT_BASE	0x404E
24 
25 struct simatic_ipc_led {
26 	unsigned int value; /* mask for io */
27 	char *name;
28 	struct led_classdev cdev;
29 };
30 
31 static struct simatic_ipc_led simatic_ipc_leds_io[] = {
32 	{1 << 15, "green:" LED_FUNCTION_STATUS "-1" },
33 	{1 << 7,  "yellow:" LED_FUNCTION_STATUS "-1" },
34 	{1 << 14, "red:" LED_FUNCTION_STATUS "-2" },
35 	{1 << 6,  "yellow:" LED_FUNCTION_STATUS "-2" },
36 	{1 << 13, "red:" LED_FUNCTION_STATUS "-3" },
37 	{1 << 5,  "yellow:" LED_FUNCTION_STATUS "-3" },
38 	{ }
39 };
40 
41 static struct resource simatic_ipc_led_io_res =
42 	DEFINE_RES_IO_NAMED(SIMATIC_IPC_LED_PORT_BASE, SZ_2, KBUILD_MODNAME);
43 
44 static DEFINE_SPINLOCK(reg_lock);
45 
46 static inline struct simatic_ipc_led *cdev_to_led(struct led_classdev *led_cd)
47 {
48 	return container_of(led_cd, struct simatic_ipc_led, cdev);
49 }
50 
51 static void simatic_ipc_led_set_io(struct led_classdev *led_cd,
52 				   enum led_brightness brightness)
53 {
54 	struct simatic_ipc_led *led = cdev_to_led(led_cd);
55 	unsigned long flags;
56 	unsigned int val;
57 
58 	spin_lock_irqsave(&reg_lock, flags);
59 
60 	val = inw(SIMATIC_IPC_LED_PORT_BASE);
61 	if (brightness == LED_OFF)
62 		outw(val | led->value, SIMATIC_IPC_LED_PORT_BASE);
63 	else
64 		outw(val & ~led->value, SIMATIC_IPC_LED_PORT_BASE);
65 
66 	spin_unlock_irqrestore(&reg_lock, flags);
67 }
68 
69 static enum led_brightness simatic_ipc_led_get_io(struct led_classdev *led_cd)
70 {
71 	struct simatic_ipc_led *led = cdev_to_led(led_cd);
72 
73 	return inw(SIMATIC_IPC_LED_PORT_BASE) & led->value ? LED_OFF : led_cd->max_brightness;
74 }
75 
76 static int simatic_ipc_leds_probe(struct platform_device *pdev)
77 {
78 	const struct simatic_ipc_platform *plat = pdev->dev.platform_data;
79 	struct device *dev = &pdev->dev;
80 	struct simatic_ipc_led *ipcled;
81 	struct led_classdev *cdev;
82 	struct resource *res;
83 	int err;
84 
85 	switch (plat->devmode) {
86 	case SIMATIC_IPC_DEVICE_227D:
87 	case SIMATIC_IPC_DEVICE_427E:
88 		res = &simatic_ipc_led_io_res;
89 		ipcled = simatic_ipc_leds_io;
90 		/* on 227D the two bytes work the other way araound */
91 		if (plat->devmode == SIMATIC_IPC_DEVICE_227D) {
92 			while (ipcled->value) {
93 				ipcled->value = swab16(ipcled->value);
94 				ipcled++;
95 			}
96 			ipcled = simatic_ipc_leds_io;
97 		}
98 		if (!devm_request_region(dev, res->start, resource_size(res), KBUILD_MODNAME)) {
99 			dev_err(dev, "Unable to register IO resource at %pR\n", res);
100 			return -EBUSY;
101 		}
102 		break;
103 	default:
104 		return -ENODEV;
105 	}
106 
107 	while (ipcled->value) {
108 		cdev = &ipcled->cdev;
109 		cdev->brightness_set = simatic_ipc_led_set_io;
110 		cdev->brightness_get = simatic_ipc_led_get_io;
111 		cdev->max_brightness = LED_ON;
112 		cdev->name = ipcled->name;
113 
114 		err = devm_led_classdev_register(dev, cdev);
115 		if (err < 0)
116 			return err;
117 		ipcled++;
118 	}
119 
120 	return 0;
121 }
122 
123 static struct platform_driver simatic_ipc_led_driver = {
124 	.probe = simatic_ipc_leds_probe,
125 	.driver = {
126 		.name = KBUILD_MODNAME,
127 	}
128 };
129 
130 module_platform_driver(simatic_ipc_led_driver);
131 
132 MODULE_LICENSE("GPL v2");
133 MODULE_ALIAS("platform:" KBUILD_MODNAME);
134 MODULE_AUTHOR("Henning Schild <henning.schild@siemens.com>");
135