xref: /openbmc/linux/arch/mips/rb532/gpio.c (revision 46f28427)
1 /*
2  *  Miscellaneous functions for IDT EB434 board
3  *
4  *  Copyright 2004 IDT Inc. (rischelp@idt.com)
5  *  Copyright 2006 Phil Sutter <n0-1@freewrt.org>
6  *  Copyright 2007 Florian Fainelli <florian@openwrt.org>
7  *
8  *  This program is free software; you can redistribute  it and/or modify it
9  *  under  the terms of  the GNU General  Public License as published by the
10  *  Free Software Foundation;  either version 2 of the  License, or (at your
11  *  option) any later version.
12  *
13  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
14  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
15  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
16  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
17  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
19  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
21  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23  *
24  *  You should have received a copy of the  GNU General Public License along
25  *  with this program; if not, write  to the Free Software Foundation, Inc.,
26  *  675 Mass Ave, Cambridge, MA 02139, USA.
27  */
28 
29 #include <linux/kernel.h>
30 #include <linux/init.h>
31 #include <linux/types.h>
32 #include <linux/export.h>
33 #include <linux/spinlock.h>
34 #include <linux/platform_device.h>
35 #include <linux/gpio/driver.h>
36 
37 #include <asm/mach-rc32434/rb.h>
38 #include <asm/mach-rc32434/gpio.h>
39 
40 #define GPIOBASE	0x050000
41 /* Offsets relative to GPIOBASE */
42 #define GPIOFUNC	0x00
43 #define GPIOCFG		0x04
44 #define GPIOD		0x08
45 #define GPIOILEVEL	0x0C
46 #define GPIOISTAT	0x10
47 #define GPIONMIEN	0x14
48 #define IMASK6		0x38
49 
50 struct rb532_gpio_chip {
51 	struct gpio_chip chip;
52 	void __iomem	 *regbase;
53 };
54 
55 static struct resource rb532_gpio_reg0_res[] = {
56 	{
57 		.name	= "gpio_reg0",
58 		.start	= REGBASE + GPIOBASE,
59 		.end	= REGBASE + GPIOBASE + sizeof(struct rb532_gpio_reg) - 1,
60 		.flags	= IORESOURCE_MEM,
61 	}
62 };
63 
64 /* rb532_set_bit - sanely set a bit
65  *
66  * bitval: new value for the bit
67  * offset: bit index in the 4 byte address range
68  * ioaddr: 4 byte aligned address being altered
69  */
70 static inline void rb532_set_bit(unsigned bitval,
71 		unsigned offset, void __iomem *ioaddr)
72 {
73 	unsigned long flags;
74 	u32 val;
75 
76 	local_irq_save(flags);
77 
78 	val = readl(ioaddr);
79 	val &= ~(!bitval << offset);   /* unset bit if bitval == 0 */
80 	val |= (!!bitval << offset);   /* set bit if bitval == 1 */
81 	writel(val, ioaddr);
82 
83 	local_irq_restore(flags);
84 }
85 
86 /* rb532_get_bit - read a bit
87  *
88  * returns the boolean state of the bit, which may be > 1
89  */
90 static inline int rb532_get_bit(unsigned offset, void __iomem *ioaddr)
91 {
92 	return readl(ioaddr) & (1 << offset);
93 }
94 
95 /*
96  * Return GPIO level */
97 static int rb532_gpio_get(struct gpio_chip *chip, unsigned offset)
98 {
99 	struct rb532_gpio_chip	*gpch;
100 
101 	gpch = gpiochip_get_data(chip);
102 	return !!rb532_get_bit(offset, gpch->regbase + GPIOD);
103 }
104 
105 /*
106  * Set output GPIO level
107  */
108 static void rb532_gpio_set(struct gpio_chip *chip,
109 				unsigned offset, int value)
110 {
111 	struct rb532_gpio_chip	*gpch;
112 
113 	gpch = gpiochip_get_data(chip);
114 	rb532_set_bit(value, offset, gpch->regbase + GPIOD);
115 }
116 
117 /*
118  * Set GPIO direction to input
119  */
120 static int rb532_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
121 {
122 	struct rb532_gpio_chip	*gpch;
123 
124 	gpch = gpiochip_get_data(chip);
125 
126 	/* disable alternate function in case it's set */
127 	rb532_set_bit(0, offset, gpch->regbase + GPIOFUNC);
128 
129 	rb532_set_bit(0, offset, gpch->regbase + GPIOCFG);
130 	return 0;
131 }
132 
133 /*
134  * Set GPIO direction to output
135  */
136 static int rb532_gpio_direction_output(struct gpio_chip *chip,
137 					unsigned offset, int value)
138 {
139 	struct rb532_gpio_chip	*gpch;
140 
141 	gpch = gpiochip_get_data(chip);
142 
143 	/* disable alternate function in case it's set */
144 	rb532_set_bit(0, offset, gpch->regbase + GPIOFUNC);
145 
146 	/* set the initial output value */
147 	rb532_set_bit(value, offset, gpch->regbase + GPIOD);
148 
149 	rb532_set_bit(1, offset, gpch->regbase + GPIOCFG);
150 	return 0;
151 }
152 
153 static int rb532_gpio_to_irq(struct gpio_chip *chip, unsigned gpio)
154 {
155 	return 8 + 4 * 32 + gpio;
156 }
157 
158 static struct rb532_gpio_chip rb532_gpio_chip[] = {
159 	[0] = {
160 		.chip = {
161 			.label			= "gpio0",
162 			.direction_input	= rb532_gpio_direction_input,
163 			.direction_output	= rb532_gpio_direction_output,
164 			.get			= rb532_gpio_get,
165 			.set			= rb532_gpio_set,
166 			.to_irq			= rb532_gpio_to_irq,
167 			.base			= 0,
168 			.ngpio			= 32,
169 		},
170 	},
171 };
172 
173 /*
174  * Set GPIO interrupt level
175  */
176 void rb532_gpio_set_ilevel(int bit, unsigned gpio)
177 {
178 	rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOILEVEL);
179 }
180 EXPORT_SYMBOL(rb532_gpio_set_ilevel);
181 
182 /*
183  * Set GPIO interrupt status
184  */
185 void rb532_gpio_set_istat(int bit, unsigned gpio)
186 {
187 	rb532_set_bit(bit, gpio, rb532_gpio_chip->regbase + GPIOISTAT);
188 }
189 EXPORT_SYMBOL(rb532_gpio_set_istat);
190 
191 /*
192  * Configure GPIO alternate function
193  */
194 void rb532_gpio_set_func(unsigned gpio)
195 {
196        rb532_set_bit(1, gpio, rb532_gpio_chip->regbase + GPIOFUNC);
197 }
198 EXPORT_SYMBOL(rb532_gpio_set_func);
199 
200 int __init rb532_gpio_init(void)
201 {
202 	struct resource *r;
203 
204 	r = rb532_gpio_reg0_res;
205 	rb532_gpio_chip->regbase = ioremap(r->start, resource_size(r));
206 
207 	if (!rb532_gpio_chip->regbase) {
208 		printk(KERN_ERR "rb532: cannot remap GPIO register 0\n");
209 		return -ENXIO;
210 	}
211 
212 	/* Register our GPIO chip */
213 	gpiochip_add_data(&rb532_gpio_chip->chip, rb532_gpio_chip);
214 
215 	return 0;
216 }
217 arch_initcall(rb532_gpio_init);
218