1// SPDX-License-Identifier: GPL-2.0
2// SPI driven IR LED device driver
3//
4// Copyright (c) 2016 Samsung Electronics Co., Ltd.
5// Copyright (c) Andi Shyti <andi@etezian.org>
6
7#include <linux/delay.h>
8#include <linux/fs.h>
9#include <linux/module.h>
10#include <linux/mutex.h>
11#include <linux/of_gpio.h>
12#include <linux/regulator/consumer.h>
13#include <linux/spi/spi.h>
14#include <media/rc-core.h>
15
16#define IR_SPI_DRIVER_NAME "ir-spi"
17
18#define IR_SPI_DEFAULT_FREQUENCY 38000
19#define IR_SPI_MAX_BUFSIZE 4096
20
21struct ir_spi_data {
22 u32 freq;
23 bool negated;
24
25 u16 tx_buf[IR_SPI_MAX_BUFSIZE];
26 u16 pulse;
27 u16 space;
28
29 struct rc_dev *rc;
30 struct spi_device *spi;
31 struct regulator *regulator;
32};
33
34static int ir_spi_tx(struct rc_dev *dev,
35 unsigned int *buffer, unsigned int count)
36{
37 int i;
38 int ret;
39 unsigned int len = 0;
40 struct ir_spi_data *idata = dev->priv;
41 struct spi_transfer xfer;
42
43 /* convert the pulse/space signal to raw binary signal */
44 for (i = 0; i < count; i++) {
45 unsigned int periods;
46 int j;
47 u16 val;
48
49 periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
50
51 if (len + periods >= IR_SPI_MAX_BUFSIZE)
52 return -EINVAL;
53
54 /*
55 * the first value in buffer is a pulse, so that 0, 2, 4, ...
56 * contain a pulse duration. On the contrary, 1, 3, 5, ...
57 * contain a space duration.
58 */
59 val = (i % 2) ? idata->space : idata->pulse;
60 for (j = 0; j < periods; j++)
61 idata->tx_buf[len++] = val;
62 }
63
64 memset(&xfer, 0, sizeof(xfer));
65
66 xfer.speed_hz = idata->freq * 16;
67 xfer.len = len * sizeof(*idata->tx_buf);
68 xfer.tx_buf = idata->tx_buf;
69
70 ret = regulator_enable(regulator: idata->regulator);
71 if (ret)
72 return ret;
73
74 ret = spi_sync_transfer(spi: idata->spi, xfers: &xfer, num_xfers: 1);
75 if (ret)
76 dev_err(&idata->spi->dev, "unable to deliver the signal\n");
77
78 regulator_disable(regulator: idata->regulator);
79
80 return ret ? ret : count;
81}
82
83static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
84{
85 struct ir_spi_data *idata = dev->priv;
86
87 if (!carrier)
88 return -EINVAL;
89
90 idata->freq = carrier;
91
92 return 0;
93}
94
95static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
96{
97 struct ir_spi_data *idata = dev->priv;
98 int bits = (duty_cycle * 15) / 100;
99
100 idata->pulse = GENMASK(bits, 0);
101
102 if (idata->negated) {
103 idata->pulse = ~idata->pulse;
104 idata->space = 0xffff;
105 } else {
106 idata->space = 0;
107 }
108
109 return 0;
110}
111
112static int ir_spi_probe(struct spi_device *spi)
113{
114 int ret;
115 u8 dc;
116 struct ir_spi_data *idata;
117
118 idata = devm_kzalloc(dev: &spi->dev, size: sizeof(*idata), GFP_KERNEL);
119 if (!idata)
120 return -ENOMEM;
121
122 idata->regulator = devm_regulator_get(dev: &spi->dev, id: "irda_regulator");
123 if (IS_ERR(ptr: idata->regulator))
124 return PTR_ERR(ptr: idata->regulator);
125
126 idata->rc = devm_rc_allocate_device(dev: &spi->dev, RC_DRIVER_IR_RAW_TX);
127 if (!idata->rc)
128 return -ENOMEM;
129
130 idata->rc->tx_ir = ir_spi_tx;
131 idata->rc->s_tx_carrier = ir_spi_set_tx_carrier;
132 idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
133 idata->rc->device_name = "IR SPI";
134 idata->rc->driver_name = IR_SPI_DRIVER_NAME;
135 idata->rc->priv = idata;
136 idata->spi = spi;
137
138 idata->negated = of_property_read_bool(np: spi->dev.of_node,
139 propname: "led-active-low");
140 ret = of_property_read_u8(np: spi->dev.of_node, propname: "duty-cycle", out_value: &dc);
141 if (ret)
142 dc = 50;
143
144 /* ir_spi_set_duty_cycle cannot fail,
145 * it returns int to be compatible with the
146 * rc->s_tx_duty_cycle function
147 */
148 ir_spi_set_duty_cycle(dev: idata->rc, duty_cycle: dc);
149
150 idata->freq = IR_SPI_DEFAULT_FREQUENCY;
151
152 return devm_rc_register_device(parent: &spi->dev, dev: idata->rc);
153}
154
155static const struct of_device_id ir_spi_of_match[] = {
156 { .compatible = "ir-spi-led" },
157 {},
158};
159MODULE_DEVICE_TABLE(of, ir_spi_of_match);
160
161static const struct spi_device_id ir_spi_ids[] = {
162 { "ir-spi-led" },
163 {},
164};
165MODULE_DEVICE_TABLE(spi, ir_spi_ids);
166
167static struct spi_driver ir_spi_driver = {
168 .probe = ir_spi_probe,
169 .id_table = ir_spi_ids,
170 .driver = {
171 .name = IR_SPI_DRIVER_NAME,
172 .of_match_table = ir_spi_of_match,
173 },
174};
175
176module_spi_driver(ir_spi_driver);
177
178MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
179MODULE_DESCRIPTION("SPI IR LED");
180MODULE_LICENSE("GPL v2");
181

source code of linux/drivers/media/rc/ir-spi.c