1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * PPC4xx gpio driver
4 *
5 * Copyright (c) 2008 Harris Corporation
6 * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
7 * Copyright (c) MontaVista Software, Inc. 2008.
8 *
9 * Author: Steve Falco <sfalco@harris.com>
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/init.h>
14 #include <linux/spinlock.h>
15 #include <linux/io.h>
16 #include <linux/of.h>
17 #include <linux/of_gpio.h>
18 #include <linux/gpio/driver.h>
19 #include <linux/types.h>
20 #include <linux/slab.h>
21
22 #define GPIO_MASK(gpio) (0x80000000 >> (gpio))
23 #define GPIO_MASK2(gpio) (0xc0000000 >> ((gpio) * 2))
24
25 /* Physical GPIO register layout */
26 struct ppc4xx_gpio {
27 __be32 or;
28 __be32 tcr;
29 __be32 osrl;
30 __be32 osrh;
31 __be32 tsrl;
32 __be32 tsrh;
33 __be32 odr;
34 __be32 ir;
35 __be32 rr1;
36 __be32 rr2;
37 __be32 rr3;
38 __be32 reserved1;
39 __be32 isr1l;
40 __be32 isr1h;
41 __be32 isr2l;
42 __be32 isr2h;
43 __be32 isr3l;
44 __be32 isr3h;
45 };
46
47 struct ppc4xx_gpio_chip {
48 struct of_mm_gpio_chip mm_gc;
49 spinlock_t lock;
50 };
51
52 /*
53 * GPIO LIB API implementation for GPIOs
54 *
55 * There are a maximum of 32 gpios in each gpio controller.
56 */
57
ppc4xx_gpio_get(struct gpio_chip * gc,unsigned int gpio)58 static int ppc4xx_gpio_get(struct gpio_chip *gc, unsigned int gpio)
59 {
60 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
61 struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
62
63 return !!(in_be32(®s->ir) & GPIO_MASK(gpio));
64 }
65
66 static inline void
__ppc4xx_gpio_set(struct gpio_chip * gc,unsigned int gpio,int val)67 __ppc4xx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
68 {
69 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
70 struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
71
72 if (val)
73 setbits32(®s->or, GPIO_MASK(gpio));
74 else
75 clrbits32(®s->or, GPIO_MASK(gpio));
76 }
77
78 static void
ppc4xx_gpio_set(struct gpio_chip * gc,unsigned int gpio,int val)79 ppc4xx_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
80 {
81 struct ppc4xx_gpio_chip *chip = gpiochip_get_data(gc);
82 unsigned long flags;
83
84 spin_lock_irqsave(&chip->lock, flags);
85
86 __ppc4xx_gpio_set(gc, gpio, val);
87
88 spin_unlock_irqrestore(&chip->lock, flags);
89
90 pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
91 }
92
ppc4xx_gpio_dir_in(struct gpio_chip * gc,unsigned int gpio)93 static int ppc4xx_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
94 {
95 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
96 struct ppc4xx_gpio_chip *chip = gpiochip_get_data(gc);
97 struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
98 unsigned long flags;
99
100 spin_lock_irqsave(&chip->lock, flags);
101
102 /* Disable open-drain function */
103 clrbits32(®s->odr, GPIO_MASK(gpio));
104
105 /* Float the pin */
106 clrbits32(®s->tcr, GPIO_MASK(gpio));
107
108 /* Bits 0-15 use TSRL/OSRL, bits 16-31 use TSRH/OSRH */
109 if (gpio < 16) {
110 clrbits32(®s->osrl, GPIO_MASK2(gpio));
111 clrbits32(®s->tsrl, GPIO_MASK2(gpio));
112 } else {
113 clrbits32(®s->osrh, GPIO_MASK2(gpio));
114 clrbits32(®s->tsrh, GPIO_MASK2(gpio));
115 }
116
117 spin_unlock_irqrestore(&chip->lock, flags);
118
119 return 0;
120 }
121
122 static int
ppc4xx_gpio_dir_out(struct gpio_chip * gc,unsigned int gpio,int val)123 ppc4xx_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
124 {
125 struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
126 struct ppc4xx_gpio_chip *chip = gpiochip_get_data(gc);
127 struct ppc4xx_gpio __iomem *regs = mm_gc->regs;
128 unsigned long flags;
129
130 spin_lock_irqsave(&chip->lock, flags);
131
132 /* First set initial value */
133 __ppc4xx_gpio_set(gc, gpio, val);
134
135 /* Disable open-drain function */
136 clrbits32(®s->odr, GPIO_MASK(gpio));
137
138 /* Drive the pin */
139 setbits32(®s->tcr, GPIO_MASK(gpio));
140
141 /* Bits 0-15 use TSRL, bits 16-31 use TSRH */
142 if (gpio < 16) {
143 clrbits32(®s->osrl, GPIO_MASK2(gpio));
144 clrbits32(®s->tsrl, GPIO_MASK2(gpio));
145 } else {
146 clrbits32(®s->osrh, GPIO_MASK2(gpio));
147 clrbits32(®s->tsrh, GPIO_MASK2(gpio));
148 }
149
150 spin_unlock_irqrestore(&chip->lock, flags);
151
152 pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
153
154 return 0;
155 }
156
ppc4xx_add_gpiochips(void)157 static int __init ppc4xx_add_gpiochips(void)
158 {
159 struct device_node *np;
160
161 for_each_compatible_node(np, NULL, "ibm,ppc4xx-gpio") {
162 int ret;
163 struct ppc4xx_gpio_chip *ppc4xx_gc;
164 struct of_mm_gpio_chip *mm_gc;
165 struct gpio_chip *gc;
166
167 ppc4xx_gc = kzalloc(sizeof(*ppc4xx_gc), GFP_KERNEL);
168 if (!ppc4xx_gc) {
169 ret = -ENOMEM;
170 goto err;
171 }
172
173 spin_lock_init(&ppc4xx_gc->lock);
174
175 mm_gc = &ppc4xx_gc->mm_gc;
176 gc = &mm_gc->gc;
177
178 gc->ngpio = 32;
179 gc->direction_input = ppc4xx_gpio_dir_in;
180 gc->direction_output = ppc4xx_gpio_dir_out;
181 gc->get = ppc4xx_gpio_get;
182 gc->set = ppc4xx_gpio_set;
183
184 ret = of_mm_gpiochip_add_data(np, mm_gc, ppc4xx_gc);
185 if (ret)
186 goto err;
187 continue;
188 err:
189 pr_err("%pOF: registration failed with status %d\n", np, ret);
190 kfree(ppc4xx_gc);
191 /* try others anyway */
192 }
193 return 0;
194 }
195 arch_initcall(ppc4xx_add_gpiochips);
196