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_MAX_BUFSIZE 4096
25
26 struct ir_spi_data {
27 u32 freq;
28 bool negated;
29
30 u16 tx_buf[IR_SPI_MAX_BUFSIZE];
31 u16 pulse;
32 u16 space;
33
34 struct rc_dev *rc;
35 struct spi_device *spi;
36 struct regulator *regulator;
37 };
38
ir_spi_tx(struct rc_dev * dev,unsigned int * buffer,unsigned int count)39 static int ir_spi_tx(struct rc_dev *dev, unsigned int *buffer, unsigned int count)
40 {
41 int i;
42 int ret;
43 unsigned int len = 0;
44 struct ir_spi_data *idata = dev->priv;
45 struct spi_transfer xfer;
46
47 /* convert the pulse/space signal to raw binary signal */
48 for (i = 0; i < count; i++) {
49 unsigned int periods;
50 int j;
51 u16 val;
52
53 periods = DIV_ROUND_CLOSEST(buffer[i] * idata->freq, 1000000);
54
55 if (len + periods >= IR_SPI_MAX_BUFSIZE)
56 return -EINVAL;
57
58 /*
59 * The first value in buffer is a pulse, so that 0, 2, 4, ...
60 * contain a pulse duration. On the contrary, 1, 3, 5, ...
61 * contain a space duration.
62 */
63 val = (i % 2) ? idata->space : idata->pulse;
64 for (j = 0; j < periods; j++)
65 idata->tx_buf[len++] = val;
66 }
67
68 memset(&xfer, 0, sizeof(xfer));
69
70 xfer.speed_hz = idata->freq * 16;
71 xfer.len = len * sizeof(*idata->tx_buf);
72 xfer.tx_buf = idata->tx_buf;
73
74 ret = regulator_enable(idata->regulator);
75 if (ret)
76 return ret;
77
78 ret = spi_sync_transfer(idata->spi, &xfer, 1);
79 if (ret)
80 dev_err(&idata->spi->dev, "unable to deliver the signal\n");
81
82 regulator_disable(idata->regulator);
83
84 return ret ? ret : count;
85 }
86
ir_spi_set_tx_carrier(struct rc_dev * dev,u32 carrier)87 static int ir_spi_set_tx_carrier(struct rc_dev *dev, u32 carrier)
88 {
89 struct ir_spi_data *idata = dev->priv;
90
91 if (!carrier)
92 return -EINVAL;
93
94 idata->freq = carrier;
95
96 return 0;
97 }
98
ir_spi_set_duty_cycle(struct rc_dev * dev,u32 duty_cycle)99 static int ir_spi_set_duty_cycle(struct rc_dev *dev, u32 duty_cycle)
100 {
101 struct ir_spi_data *idata = dev->priv;
102 int bits = (duty_cycle * 15) / 100;
103
104 idata->pulse = GENMASK(bits, 0);
105
106 if (idata->negated) {
107 idata->pulse = ~idata->pulse;
108 idata->space = 0xffff;
109 } else {
110 idata->space = 0;
111 }
112
113 return 0;
114 }
115
ir_spi_probe(struct spi_device * spi)116 static int ir_spi_probe(struct spi_device *spi)
117 {
118 struct device *dev = &spi->dev;
119 int ret;
120 u8 dc;
121 struct ir_spi_data *idata;
122
123 idata = devm_kzalloc(dev, sizeof(*idata), GFP_KERNEL);
124 if (!idata)
125 return -ENOMEM;
126
127 idata->regulator = devm_regulator_get(dev, "irda_regulator");
128 if (IS_ERR(idata->regulator))
129 return PTR_ERR(idata->regulator);
130
131 idata->rc = devm_rc_allocate_device(&spi->dev, RC_DRIVER_IR_RAW_TX);
132 if (!idata->rc)
133 return -ENOMEM;
134
135 idata->rc->tx_ir = ir_spi_tx;
136 idata->rc->s_tx_carrier = ir_spi_set_tx_carrier;
137 idata->rc->s_tx_duty_cycle = ir_spi_set_duty_cycle;
138 idata->rc->device_name = "IR SPI";
139 idata->rc->driver_name = IR_SPI_DRIVER_NAME;
140 idata->rc->priv = idata;
141 idata->spi = spi;
142
143 idata->negated = device_property_read_bool(dev, "led-active-low");
144 ret = device_property_read_u8(dev, "duty-cycle", &dc);
145 if (ret)
146 dc = 50;
147
148 /*
149 * ir_spi_set_duty_cycle() cannot fail, it returns int
150 * to be compatible with the rc->s_tx_duty_cycle function.
151 */
152 ir_spi_set_duty_cycle(idata->rc, dc);
153
154 idata->freq = IR_SPI_DEFAULT_FREQUENCY;
155
156 return devm_rc_register_device(dev, idata->rc);
157 }
158
159 static const struct of_device_id ir_spi_of_match[] = {
160 { .compatible = "ir-spi-led" },
161 {}
162 };
163 MODULE_DEVICE_TABLE(of, ir_spi_of_match);
164
165 static const struct spi_device_id ir_spi_ids[] = {
166 { "ir-spi-led" },
167 {}
168 };
169 MODULE_DEVICE_TABLE(spi, ir_spi_ids);
170
171 static struct spi_driver ir_spi_driver = {
172 .probe = ir_spi_probe,
173 .id_table = ir_spi_ids,
174 .driver = {
175 .name = IR_SPI_DRIVER_NAME,
176 .of_match_table = ir_spi_of_match,
177 },
178 };
179 module_spi_driver(ir_spi_driver);
180
181 MODULE_AUTHOR("Andi Shyti <andi@etezian.org>");
182 MODULE_DESCRIPTION("SPI IR LED");
183 MODULE_LICENSE("GPL v2");
184