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
21 struct 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
ir_spi_tx(struct rc_dev * dev,unsigned int * buffer,unsigned int count)34 static 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(idata->regulator);
71 if (ret)
72 return ret;
73
74 ret = spi_sync_transfer(idata->spi, &xfer, 1);
75 if (ret)
76 dev_err(&idata->spi->dev, "unable to deliver the signal\n");
77
78 regulator_disable(idata->regulator);
79
80 return ret ? ret : count;
81 }
82
ir_spi_set_tx_carrier(struct rc_dev * dev,u32 carrier)83 static 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
ir_spi_set_duty_cycle(struct rc_dev * dev,u32 duty_cycle)95 static 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
ir_spi_probe(struct spi_device * spi)112 static 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(&spi->dev, sizeof(*idata), GFP_KERNEL);
119 if (!idata)
120 return -ENOMEM;
121
122 idata->regulator = devm_regulator_get(&spi->dev, "irda_regulator");
123 if (IS_ERR(idata->regulator))
124 return PTR_ERR(idata->regulator);
125
126 idata->rc = devm_rc_allocate_device(&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(spi->dev.of_node,
139 "led-active-low");
140 ret = of_property_read_u8(spi->dev.of_node, "duty-cycle", &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(idata->rc, dc);
149
150 idata->freq = IR_SPI_DEFAULT_FREQUENCY;
151
152 return devm_rc_register_device(&spi->dev, idata->rc);
153 }
154
155 static const struct of_device_id ir_spi_of_match[] = {
156 { .compatible = "ir-spi-led" },
157 {},
158 };
159 MODULE_DEVICE_TABLE(of, ir_spi_of_match);
160
161 static struct spi_driver ir_spi_driver = {
162 .probe = ir_spi_probe,
163 .driver = {
164 .name = IR_SPI_DRIVER_NAME,
165 .of_match_table = ir_spi_of_match,
166 },
167 };
168
169 module_spi_driver(ir_spi_driver);
170
171 MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
172 MODULE_DESCRIPTION("SPI IR LED");
173 MODULE_LICENSE("GPL v2");
174