1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
/*
* PCF8575 I2C GPIO EXPANDER DRIVER
*
* Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
*
* Vignesh R <vigneshr@ti.com>
*
* SPDX-License-Identifier: GPL-2.0
*
*
* Driver for TI PCF-8575 16-bit I2C gpio expander. Based on
* gpio-pcf857x Linux Kernel(v4.7) driver.
*
* Copyright (C) 2007 David Brownell
*
*/
/*
* NOTE: The driver and devicetree bindings are borrowed from Linux
* Kernel, but driver does not support all PCF857x devices. It currently
* supports PCF8575 16-bit expander by TI and NXP.
*
* TODO(vigneshr@ti.com):
* Support 8 bit PCF857x compatible expanders.
*/
#include <common.h>
#include <dm.h>
#include <i2c.h>
#include <asm-generic/gpio.h>
DECLARE_GLOBAL_DATA_PTR;
struct pcf8575_chip {
int gpio_count; /* No. GPIOs supported by the chip */
/* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
* We can't actually know whether a pin is configured (a) as output
* and driving the signal low, or (b) as input and reporting a low
* value ... without knowing the last value written since the chip
* came out of reset (if any). We can't read the latched output.
* In short, the only reliable solution for setting up pin direction
* is to do it explicitly.
*
* Using "out" avoids that trouble. When left initialized to zero,
* our software copy of the "latch" then matches the chip's all-ones
* reset state. Otherwise it flags pins to be driven low.
*/
unsigned int out; /* software latch */
const char *bank_name; /* Name of the expander bank */
};
/* Read/Write to 16-bit I/O expander */
static int pcf8575_i2c_write_le16(struct udevice *dev, unsigned int word)
{
struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
u8 buf[2] = { word & 0xff, word >> 8, };
int ret;
ret = dm_i2c_write(dev, 0, buf, 2);
if (ret)
printf("%s i2c write failed to addr %x\n", __func__,
chip->chip_addr);
return ret;
}
static int pcf8575_i2c_read_le16(struct udevice *dev)
{
struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
u8 buf[2];
int ret;
ret = dm_i2c_read(dev, 0, buf, 2);
if (ret) {
printf("%s i2c read failed from addr %x\n", __func__,
chip->chip_addr);
return ret;
}
return (buf[1] << 8) | buf[0];
}
static int pcf8575_direction_input(struct udevice *dev, unsigned offset)
{
struct pcf8575_chip *plat = dev_get_platdata(dev);
int status;
plat->out |= BIT(offset);
status = pcf8575_i2c_write_le16(dev, plat->out);
return status;
}
static int pcf8575_direction_output(struct udevice *dev,
unsigned int offset, int value)
{
struct pcf8575_chip *plat = dev_get_platdata(dev);
int ret;
if (value)
plat->out |= BIT(offset);
else
plat->out &= ~BIT(offset);
ret = pcf8575_i2c_write_le16(dev, plat->out);
return ret;
}
static int pcf8575_get_value(struct udevice *dev, unsigned int offset)
{
int value;
value = pcf8575_i2c_read_le16(dev);
return (value < 0) ? value : ((value & BIT(offset)) >> offset);
}
static int pcf8575_set_value(struct udevice *dev, unsigned int offset,
int value)
{
return pcf8575_direction_output(dev, offset, value);
}
static int pcf8575_ofdata_platdata(struct udevice *dev)
{
struct pcf8575_chip *plat = dev_get_platdata(dev);
struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
int n_latch;
uc_priv->gpio_count = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev),
"gpio-count", 16);
uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev_of_offset(dev),
"gpio-bank-name", NULL);
if (!uc_priv->bank_name)
uc_priv->bank_name = fdt_get_name(gd->fdt_blob,
dev_of_offset(dev), NULL);
n_latch = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
"lines-initial-states", 0);
plat->out = ~n_latch;
return 0;
}
static int pcf8575_gpio_probe(struct udevice *dev)
{
struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
debug("%s GPIO controller with %d gpios probed\n",
uc_priv->bank_name, uc_priv->gpio_count);
return 0;
}
static const struct dm_gpio_ops pcf8575_gpio_ops = {
.direction_input = pcf8575_direction_input,
.direction_output = pcf8575_direction_output,
.get_value = pcf8575_get_value,
.set_value = pcf8575_set_value,
};
static const struct udevice_id pcf8575_gpio_ids[] = {
{ .compatible = "nxp,pcf8575" },
{ .compatible = "ti,pcf8575" },
{ }
};
U_BOOT_DRIVER(gpio_pcf8575) = {
.name = "gpio_pcf8575",
.id = UCLASS_GPIO,
.ops = &pcf8575_gpio_ops,
.of_match = pcf8575_gpio_ids,
.ofdata_to_platdata = pcf8575_ofdata_platdata,
.probe = pcf8575_gpio_probe,
.platdata_auto_alloc_size = sizeof(struct pcf8575_chip),
};
|
