1 /*
2  * Driver for GE FPGA based GPIO
3  *
4  * Author: Martyn Welch <martyn.welch@ge.com>
5  *
6  * 2008 (c) GE Intelligent Platforms Embedded Systems, Inc.
7  *
8  * This file is licensed under the terms of the GNU General Public License
9  * version 2.  This program is licensed "as is" without any warranty of any
10  * kind, whether express or implied.
11  */
12 
13 /* TODO
14  *
15  * Configuration of output modes (totem-pole/open-drain)
16  * Interrupt configuration - interrupts are always generated the FPGA relies on
17  * the I/O interrupt controllers mask to stop them propergating
18  */
19 
20 #include <linux/kernel.h>
21 #include <linux/io.h>
22 #include <linux/slab.h>
23 #include <linux/of_device.h>
24 #include <linux/of_address.h>
25 #include <linux/module.h>
26 #include <linux/gpio/driver.h>
27 
28 #define GEF_GPIO_DIRECT		0x00
29 #define GEF_GPIO_IN		0x04
30 #define GEF_GPIO_OUT		0x08
31 #define GEF_GPIO_TRIG		0x0C
32 #define GEF_GPIO_POLAR_A	0x10
33 #define GEF_GPIO_POLAR_B	0x14
34 #define GEF_GPIO_INT_STAT	0x18
35 #define GEF_GPIO_OVERRUN	0x1C
36 #define GEF_GPIO_MODE		0x20
37 
38 static const struct of_device_id gef_gpio_ids[] = {
39 	{
40 		.compatible	= "gef,sbc610-gpio",
41 		.data		= (void *)19,
42 	}, {
43 		.compatible	= "gef,sbc310-gpio",
44 		.data		= (void *)6,
45 	}, {
46 		.compatible	= "ge,imp3a-gpio",
47 		.data		= (void *)16,
48 	},
49 	{ }
50 };
51 MODULE_DEVICE_TABLE(of, gef_gpio_ids);
52 
gef_gpio_probe(struct platform_device * pdev)53 static int __init gef_gpio_probe(struct platform_device *pdev)
54 {
55 	struct gpio_chip *gc;
56 	void __iomem *regs;
57 	int ret;
58 
59 	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
60 	if (!gc)
61 		return -ENOMEM;
62 
63 	regs = of_iomap(pdev->dev.of_node, 0);
64 	if (!regs)
65 		return -ENOMEM;
66 
67 	ret = bgpio_init(gc, &pdev->dev, 4, regs + GEF_GPIO_IN,
68 			 regs + GEF_GPIO_OUT, NULL, NULL,
69 			 regs + GEF_GPIO_DIRECT, BGPIOF_BIG_ENDIAN_BYTE_ORDER);
70 	if (ret) {
71 		dev_err(&pdev->dev, "bgpio_init failed\n");
72 		goto err0;
73 	}
74 
75 	/* Setup pointers to chip functions */
76 	gc->label = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOF", pdev->dev.of_node);
77 	if (!gc->label) {
78 		ret = -ENOMEM;
79 		goto err0;
80 	}
81 
82 	gc->base = -1;
83 	gc->ngpio = (u16)(uintptr_t)of_device_get_match_data(&pdev->dev);
84 	gc->of_gpio_n_cells = 2;
85 	gc->of_node = pdev->dev.of_node;
86 
87 	/* This function adds a memory mapped GPIO chip */
88 	ret = devm_gpiochip_add_data(&pdev->dev, gc, NULL);
89 	if (ret)
90 		goto err0;
91 
92 	return 0;
93 err0:
94 	iounmap(regs);
95 	pr_err("%pOF: GPIO chip registration failed\n", pdev->dev.of_node);
96 	return ret;
97 };
98 
99 static struct platform_driver gef_gpio_driver = {
100 	.driver = {
101 		.name		= "gef-gpio",
102 		.of_match_table	= gef_gpio_ids,
103 	},
104 };
105 module_platform_driver_probe(gef_gpio_driver, gef_gpio_probe);
106 
107 MODULE_DESCRIPTION("GE I/O FPGA GPIO driver");
108 MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com");
109 MODULE_LICENSE("GPL");
110