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/bits.h>
8#include <linux/device.h>
9#include <linux/err.h>
10#include <linux/math.h>
11#include <linux/mod_devicetable.h>
12#include <linux/module.h>
13#include <linux/property.h>
14#include <linux/regulator/consumer.h>
15#include <linux/spi/spi.h>
16#include <linux/string.h>
17#include <linux/types.h>
18
19#include <media/rc-core.h>
20
21#define IR_SPI_DRIVER_NAME "ir-spi"
22
23#define IR_SPI_DEFAULT_FREQUENCY 38000
24#define IR_SPI_BITS_PER_PULSE 16
25
26struct ir_spi_data {
27 u32 freq;
28 bool negated;
29
30 u16 pulse;
31 u16 space;
32
33 struct rc_dev *rc;
34 struct spi_device *spi;
35 struct regulator *regulator;
36};
37
38static int ir_spi_tx(struct rc_dev *dev, unsigned int *buffer, unsigned int count)
39{
40 int i;
41 int ret;
42 unsigned int len = 0;
43 struct ir_spi_data *idata = dev->priv;
44 struct spi_transfer xfer;
45 u16 *tx_buf;
46
47 /* convert the pulse/space signal to raw binary signal */
48 for (i = 0; i < count; i++) {
49 buffer[i] = DIV_ROUND_CLOSEST_ULL((u64)buffer[i] * idata->freq,
50 1000000);
51 len += buffer[i];
52 }
53
54 tx_buf = kmalloc_array(len, sizeof(*tx_buf), GFP_KERNEL);
55 if (!tx_buf)
56 return -ENOMEM;
57
58 len = 0;
59 for (i = 0; i < count; i++) {
60 int j;
61 u16 val;
62
63 /*
64 * The first value in buffer is a pulse, so that 0, 2, 4, ...
65 * contain a pulse duration. On the contrary, 1, 3, 5, ...
66 * contain a space duration.
67 */
68 val = (i % 2) ? idata->space : idata->pulse;
69 for (j = 0; j < buffer[i]; j++)
70 tx_buf[len++] = val;
71 }
72
73 memset(&xfer, 0, sizeof(xfer));
74
75 xfer.speed_hz = idata->freq * IR_SPI_BITS_PER_PULSE;
76 xfer.len = len * sizeof(*tx_buf);
77 xfer.tx_buf = tx_buf;
78
79 ret = regulator_enable(regulator: idata->regulator);
80 if (ret)
81 goto err_free_tx_buf;
82
83 ret = spi_sync_transfer(spi: idata->spi, xfers: &xfer, num_xfers: 1);
84 if (ret)
85 dev_err(&idata->spi->dev, "unable to deliver the signal\n");
86
87 regulator_disable(regulator: idata->regulator);
88
89err_free_tx_buf:
90
91 kfree(objp: tx_buf);
92
93 return ret ? ret : count;
94}
95
96static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
97{
98 struct ir_spi_data *idata = dev->priv;
99
100 if (!carrier)
101 return -EINVAL;
102
103 if (carrier > idata->spi->max_speed_hz / IR_SPI_BITS_PER_PULSE)
104 return -EINVAL;
105
106 idata->freq = carrier;
107
108 return 0;
109}
110
111static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
112{
113 struct ir_spi_data *idata = dev->priv;
114 int bits = (duty_cycle * 15) / 100;
115
116 idata->pulse = GENMASK(bits, 0);
117
118 if (idata->negated) {
119 idata->pulse = ~idata->pulse;
120 idata->space = 0xffff;
121 } else {
122 idata->space = 0;
123 }
124
125 return 0;
126}
127
128static int ir_spi_probe(struct spi_device *spi)
129{
130 struct device *dev = &spi->dev;
131 int ret;
132 u8 dc;
133 struct ir_spi_data *idata;
134
135 idata = devm_kzalloc(dev, size: sizeof(*idata), GFP_KERNEL);
136 if (!idata)
137 return -ENOMEM;
138
139 idata->regulator = devm_regulator_get(dev, id: "irda_regulator");
140 if (IS_ERR(ptr: idata->regulator))
141 return PTR_ERR(ptr: idata->regulator);
142
143 idata->rc = devm_rc_allocate_device(dev: &spi->dev, RC_DRIVER_IR_RAW_TX);
144 if (!idata->rc)
145 return -ENOMEM;
146
147 idata->rc->tx_ir = ir_spi_tx;
148 idata->rc->s_tx_carrier = ir_spi_set_tx_carrier;
149 idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
150 idata->rc->device_name = "IR SPI";
151 idata->rc->driver_name = IR_SPI_DRIVER_NAME;
152 idata->rc->priv = idata;
153 idata->spi = spi;
154
155 idata->negated = device_property_read_bool(dev, propname: "led-active-low");
156 ret = device_property_read_u8(dev, propname: "duty-cycle", val: &dc);
157 if (ret)
158 dc = 50;
159
160 /*
161 * ir_spi_set_duty_cycle() cannot fail, it returns int
162 * to be compatible with the rc->s_tx_duty_cycle function.
163 */
164 ir_spi_set_duty_cycle(dev: idata->rc, duty_cycle: dc);
165
166 idata->freq = IR_SPI_DEFAULT_FREQUENCY;
167
168 return devm_rc_register_device(parent: dev, dev: idata->rc);
169}
170
171static const struct of_device_id ir_spi_of_match[] = {
172 { .compatible = "ir-spi-led" },
173 {}
174};
175MODULE_DEVICE_TABLE(of, ir_spi_of_match);
176
177static const struct spi_device_id ir_spi_ids[] = {
178 { "ir-spi-led" },
179 {}
180};
181MODULE_DEVICE_TABLE(spi, ir_spi_ids);
182
183static struct spi_driver ir_spi_driver = {
184 .probe = ir_spi_probe,
185 .id_table = ir_spi_ids,
186 .driver = {
187 .name = IR_SPI_DRIVER_NAME,
188 .of_match_table = ir_spi_of_match,
189 },
190};
191module_spi_driver(ir_spi_driver);
192
193MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
194MODULE_DESCRIPTION("SPI IR LED");
195MODULE_LICENSE("GPL v2");
196

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