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Peng Fan9300f712016-05-03 10:02:23 +08001/*
2 * Take drivers/gpio/gpio-74x164.c as reference.
3 *
4 * 74Hx164 - Generic serial-in/parallel-out 8-bits shift register GPIO driver
5 *
6 * Copyright (C) 2016 Peng Fan <van.freenix@gmail.com>
7 *
8 * SPDX-License-Identifier: GPL-2.0+
9 *
10 */
11
12#include <common.h>
13#include <errno.h>
14#include <dm.h>
15#include <fdtdec.h>
16#include <malloc.h>
17#include <asm/gpio.h>
18#include <asm/io.h>
19#include <dt-bindings/gpio/gpio.h>
20#include <spi.h>
21
22DECLARE_GLOBAL_DATA_PTR;
23
24/*
25 * struct gen_74x164_chip - Data for 74Hx164
26 *
27 * @oe: OE pin
28 * @nregs: number of registers
29 * @buffer: buffer for chained chips
30 */
31#define GEN_74X164_NUMBER_GPIOS 8
32
33struct gen_74x164_priv {
34 struct gpio_desc oe;
35 u32 nregs;
36 /*
37 * Since the nregs are chained, every byte sent will make
38 * the previous byte shift to the next register in the
39 * chain. Thus, the first byte sent will end up in the last
40 * register at the end of the transfer. So, to have a logical
41 * numbering, store the bytes in reverse order.
42 */
43 u8 *buffer;
44};
45
46static int gen_74x164_write_conf(struct udevice *dev)
47{
48 struct gen_74x164_priv *priv = dev_get_priv(dev);
49 int ret;
50
51 ret = dm_spi_claim_bus(dev);
52 if (ret)
53 return ret;
54
55 ret = dm_spi_xfer(dev, priv->nregs * 8, priv->buffer, NULL,
56 SPI_XFER_BEGIN | SPI_XFER_END);
57
58 dm_spi_release_bus(dev);
59
60 return ret;
61}
62
63static int gen_74x164_get_value(struct udevice *dev, unsigned offset)
64{
65 struct gen_74x164_priv *priv = dev_get_priv(dev);
66 uint bank = priv->nregs - 1 - offset / 8;
67 uint pin = offset % 8;
68
69 return (priv->buffer[bank] >> pin) & 0x1;
70}
71
72static int gen_74x164_set_value(struct udevice *dev, unsigned offset,
73 int value)
74{
75 struct gen_74x164_priv *priv = dev_get_priv(dev);
76 uint bank = priv->nregs - 1 - offset / 8;
77 uint pin = offset % 8;
78 int ret;
79
80 if (value)
81 priv->buffer[bank] |= 1 << pin;
82 else
83 priv->buffer[bank] &= ~(1 << pin);
84
85 ret = gen_74x164_write_conf(dev);
86 if (ret)
87 return ret;
88
89 return 0;
90}
91
92static int gen_74x164_direction_input(struct udevice *dev, unsigned offset)
93{
94 return -ENOSYS;
95}
96
97static int gen_74x164_direction_output(struct udevice *dev, unsigned offset,
98 int value)
99{
100 return gen_74x164_set_value(dev, offset, value);
101}
102
103static int gen_74x164_get_function(struct udevice *dev, unsigned offset)
104{
105 return GPIOF_OUTPUT;
106}
107
108static int gen_74x164_xlate(struct udevice *dev, struct gpio_desc *desc,
Simon Glass3a571232017-05-18 20:09:18 -0600109 struct ofnode_phandle_args *args)
Peng Fan9300f712016-05-03 10:02:23 +0800110{
111 desc->offset = args->args[0];
112 desc->flags = args->args[1] & GPIO_ACTIVE_LOW ? GPIOD_ACTIVE_LOW : 0;
113
114 return 0;
115}
116
117static const struct dm_gpio_ops gen_74x164_ops = {
118 .direction_input = gen_74x164_direction_input,
119 .direction_output = gen_74x164_direction_output,
120 .get_value = gen_74x164_get_value,
121 .set_value = gen_74x164_set_value,
122 .get_function = gen_74x164_get_function,
123 .xlate = gen_74x164_xlate,
124};
125
126static int gen_74x164_probe(struct udevice *dev)
127{
128 struct gen_74x164_priv *priv = dev_get_priv(dev);
129 struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
130 char *str, name[32];
131 int ret;
132 const void *fdt = gd->fdt_blob;
Simon Glasse160f7d2017-01-17 16:52:55 -0700133 int node = dev_of_offset(dev);
Peng Fan9300f712016-05-03 10:02:23 +0800134
135 snprintf(name, sizeof(name), "%s_", dev->name);
136 str = strdup(name);
137 if (!str)
138 return -ENOMEM;
139
140 /*
141 * See Linux kernel:
142 * Documentation/devicetree/bindings/gpio/gpio-74x164.txt
143 */
144 priv->nregs = fdtdec_get_int(fdt, node, "registers-number", 1);
145 priv->buffer = calloc(priv->nregs, sizeof(u8));
146 if (!priv->buffer) {
147 ret = -ENOMEM;
148 goto free_str;
149 }
150
151 ret = fdtdec_get_byte_array(fdt, node, "registers-default",
152 priv->buffer, priv->nregs);
153 if (ret)
154 dev_dbg(dev, "No registers-default property\n");
155
156 ret = gpio_request_by_name(dev, "oe-gpios", 0, &priv->oe,
157 GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
158 if (ret) {
Peng Fanaab203e2017-04-13 14:09:56 +0800159 dev_dbg(dev, "No oe-pins property\n");
Peng Fan9300f712016-05-03 10:02:23 +0800160 }
161
162 uc_priv->bank_name = str;
163 uc_priv->gpio_count = priv->nregs * 8;
164
165 ret = gen_74x164_write_conf(dev);
166 if (ret)
167 goto free_buf;
168
169 dev_dbg(dev, "%s is ready\n", dev->name);
170
171 return 0;
172
173free_buf:
174 free(priv->buffer);
175free_str:
176 free(str);
177 return ret;
178}
179
180static const struct udevice_id gen_74x164_ids[] = {
181 { .compatible = "fairchild,74hc595" },
182 { }
183};
184
185U_BOOT_DRIVER(74x164) = {
186 .name = "74x164",
187 .id = UCLASS_GPIO,
188 .ops = &gen_74x164_ops,
189 .probe = gen_74x164_probe,
190 .priv_auto_alloc_size = sizeof(struct gen_74x164_priv),
191 .of_match = gen_74x164_ids,
192};