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965dc5fc MW |
1 | /* |
2 | * Driver for GE Fanuc's FPGA based GPIO pins | |
3 | * | |
4 | * Author: Martyn Welch <martyn.welch@gefanuc.com> | |
5 | * | |
6 | * 2008 (c) GE Fanuc 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/compiler.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/io.h> | |
24 | #include <linux/of.h> | |
25 | #include <linux/of_device.h> | |
26 | #include <linux/of_platform.h> | |
27 | #include <linux/of_gpio.h> | |
28 | #include <linux/gpio.h> | |
29 | ||
30 | #define GEF_GPIO_DIRECT 0x00 | |
31 | #define GEF_GPIO_IN 0x04 | |
32 | #define GEF_GPIO_OUT 0x08 | |
33 | #define GEF_GPIO_TRIG 0x0C | |
34 | #define GEF_GPIO_POLAR_A 0x10 | |
35 | #define GEF_GPIO_POLAR_B 0x14 | |
36 | #define GEF_GPIO_INT_STAT 0x18 | |
37 | #define GEF_GPIO_OVERRUN 0x1C | |
38 | #define GEF_GPIO_MODE 0x20 | |
39 | ||
40 | #define NUM_GPIO 19 | |
41 | ||
42 | static void _gef_gpio_set(void __iomem *reg, unsigned int offset, int value) | |
43 | { | |
44 | unsigned int data; | |
45 | ||
46 | data = ioread32be(reg); | |
47 | /* value: 0=low; 1=high */ | |
48 | if (value & 0x1) | |
49 | data = data | (0x1 << offset); | |
50 | else | |
51 | data = data & ~(0x1 << offset); | |
52 | ||
53 | iowrite32be(data, reg); | |
54 | } | |
55 | ||
56 | ||
57 | static int gef_gpio_dir_in(struct gpio_chip *chip, unsigned offset) | |
58 | { | |
59 | unsigned int data; | |
60 | struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip); | |
61 | ||
62 | data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT); | |
63 | data = data | (0x1 << offset); | |
64 | iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT); | |
65 | ||
66 | return 0; | |
67 | } | |
68 | ||
69 | static int gef_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int value) | |
70 | { | |
71 | unsigned int data; | |
72 | struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip); | |
73 | ||
74 | /* Set direction before switching to input */ | |
75 | _gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value); | |
76 | ||
77 | data = ioread32be(mmchip->regs + GEF_GPIO_DIRECT); | |
78 | data = data & ~(0x1 << offset); | |
79 | iowrite32be(data, mmchip->regs + GEF_GPIO_DIRECT); | |
80 | ||
81 | return 0; | |
82 | } | |
83 | ||
84 | static int gef_gpio_get(struct gpio_chip *chip, unsigned offset) | |
85 | { | |
86 | unsigned int data; | |
87 | int state = 0; | |
88 | struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip); | |
89 | ||
90 | data = ioread32be(mmchip->regs + GEF_GPIO_IN); | |
91 | state = (int)((data >> offset) & 0x1); | |
92 | ||
93 | return state; | |
94 | } | |
95 | ||
96 | static void gef_gpio_set(struct gpio_chip *chip, unsigned offset, int value) | |
97 | { | |
98 | struct of_mm_gpio_chip *mmchip = to_of_mm_gpio_chip(chip); | |
99 | ||
100 | _gef_gpio_set(mmchip->regs + GEF_GPIO_OUT, offset, value); | |
101 | } | |
102 | ||
103 | static int __init gef_gpio_init(void) | |
104 | { | |
105 | struct device_node *np; | |
106 | ||
107 | for_each_compatible_node(np, NULL, "gef,sbc610-gpio") { | |
108 | int retval; | |
109 | struct of_mm_gpio_chip *gef_gpio_chip; | |
110 | ||
111 | pr_debug("%s: Initialising GEF GPIO\n", np->full_name); | |
112 | ||
113 | /* Allocate chip structure */ | |
114 | gef_gpio_chip = kzalloc(sizeof(*gef_gpio_chip), GFP_KERNEL); | |
115 | if (!gef_gpio_chip) { | |
116 | pr_err("%s: Unable to allocate structure\n", | |
117 | np->full_name); | |
118 | continue; | |
119 | } | |
120 | ||
121 | /* Setup pointers to chip functions */ | |
122 | gef_gpio_chip->of_gc.gpio_cells = 2; | |
123 | gef_gpio_chip->of_gc.gc.ngpio = NUM_GPIO; | |
124 | gef_gpio_chip->of_gc.gc.direction_input = gef_gpio_dir_in; | |
125 | gef_gpio_chip->of_gc.gc.direction_output = gef_gpio_dir_out; | |
126 | gef_gpio_chip->of_gc.gc.get = gef_gpio_get; | |
127 | gef_gpio_chip->of_gc.gc.set = gef_gpio_set; | |
128 | ||
129 | /* This function adds a memory mapped GPIO chip */ | |
130 | retval = of_mm_gpiochip_add(np, gef_gpio_chip); | |
131 | if (retval) { | |
132 | kfree(gef_gpio_chip); | |
133 | pr_err("%s: Unable to add GPIO\n", np->full_name); | |
134 | } | |
135 | } | |
136 | ||
137 | return 0; | |
138 | }; | |
139 | arch_initcall(gef_gpio_init); | |
140 | ||
141 | MODULE_DESCRIPTION("GE Fanuc I/O FPGA GPIO driver"); | |
142 | MODULE_AUTHOR("Martyn Welch <martyn.welch@gefanuc.com"); | |
143 | MODULE_LICENSE("GPL"); |