1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/device.h>
4 #include <linux/module.h>
5 #include <linux/spi/spi.h>
6 #include <linux/delay.h>
7 
8 #include <drm/drm_print.h>
9 
10 #include "panel-samsung-s6e63m0.h"
11 
12 #define DATA_MASK	0x100
13 
14 static int s6e63m0_spi_dcs_read(struct device *dev, const u8 cmd, u8 *data)
15 {
16 	/*
17 	 * FIXME: implement reading DCS commands over SPI so we can
18 	 * properly identify which physical panel is connected.
19 	 */
20 	*data = 0;
21 
22 	return 0;
23 }
24 
25 static int s6e63m0_spi_write_word(struct device *dev, u16 data)
26 {
27 	struct spi_device *spi = to_spi_device(dev);
28 	struct spi_transfer xfer = {
29 		.len	= 2,
30 		.tx_buf = &data,
31 	};
32 	struct spi_message msg;
33 
34 	spi_message_init(&msg);
35 	spi_message_add_tail(&xfer, &msg);
36 
37 	return spi_sync(spi, &msg);
38 }
39 
40 static int s6e63m0_spi_dcs_write(struct device *dev, const u8 *data, size_t len)
41 {
42 	int ret = 0;
43 
44 	dev_dbg(dev, "SPI writing dcs seq: %*ph\n", (int)len, data);
45 	ret = s6e63m0_spi_write_word(dev, *data);
46 
47 	while (!ret && --len) {
48 		++data;
49 		ret = s6e63m0_spi_write_word(dev, *data | DATA_MASK);
50 	}
51 
52 	if (ret) {
53 		dev_err(dev, "SPI error %d writing dcs seq: %*ph\n", ret,
54 			(int)len, data);
55 	}
56 
57 	usleep_range(300, 310);
58 
59 	return ret;
60 }
61 
62 static int s6e63m0_spi_probe(struct spi_device *spi)
63 {
64 	struct device *dev = &spi->dev;
65 	int ret;
66 
67 	spi->bits_per_word = 9;
68 	spi->mode = SPI_MODE_3;
69 	ret = spi_setup(spi);
70 	if (ret < 0) {
71 		dev_err(dev, "spi setup failed.\n");
72 		return ret;
73 	}
74 	return s6e63m0_probe(dev, s6e63m0_spi_dcs_read, s6e63m0_spi_dcs_write,
75 			     false);
76 }
77 
78 static int s6e63m0_spi_remove(struct spi_device *spi)
79 {
80 	return s6e63m0_remove(&spi->dev);
81 }
82 
83 static const struct of_device_id s6e63m0_spi_of_match[] = {
84 	{ .compatible = "samsung,s6e63m0" },
85 	{ /* sentinel */ }
86 };
87 MODULE_DEVICE_TABLE(of, s6e63m0_spi_of_match);
88 
89 static struct spi_driver s6e63m0_spi_driver = {
90 	.probe			= s6e63m0_spi_probe,
91 	.remove			= s6e63m0_spi_remove,
92 	.driver			= {
93 		.name		= "panel-samsung-s6e63m0",
94 		.of_match_table = s6e63m0_spi_of_match,
95 	},
96 };
97 module_spi_driver(s6e63m0_spi_driver);
98 
99 MODULE_AUTHOR("Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>");
100 MODULE_DESCRIPTION("s6e63m0 LCD SPI Driver");
101 MODULE_LICENSE("GPL v2");
102