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 struct spi_device *spi = to_spi_device(dev); 17 u16 buf[1]; 18 u16 rbuf[1]; 19 int ret; 20 21 /* SPI buffers are always in CPU order */ 22 buf[0] = (u16)cmd; 23 ret = spi_write_then_read(spi, buf, 2, rbuf, 2); 24 dev_dbg(dev, "READ CMD: %04x RET: %04x\n", buf[0], rbuf[0]); 25 if (!ret) 26 /* These high 8 bits of the 9 contains the readout */ 27 *data = (rbuf[0] & 0x1ff) >> 1; 28 29 return ret; 30 } 31 32 static int s6e63m0_spi_write_word(struct device *dev, u16 data) 33 { 34 struct spi_device *spi = to_spi_device(dev); 35 36 /* SPI buffers are always in CPU order */ 37 return spi_write(spi, &data, 2); 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 46 /* 47 * This sends 9 bits with the first bit (bit 8) set to 0 48 * This indicates that this is a command. Anything after the 49 * command is data. 50 */ 51 ret = s6e63m0_spi_write_word(dev, *data); 52 53 while (!ret && --len) { 54 ++data; 55 /* This sends 9 bits with the first bit (bit 8) set to 1 */ 56 ret = s6e63m0_spi_write_word(dev, *data | DATA_MASK); 57 } 58 59 if (ret) { 60 dev_err(dev, "SPI error %d writing dcs seq: %*ph\n", ret, 61 (int)len, data); 62 } 63 64 usleep_range(300, 310); 65 66 return ret; 67 } 68 69 static int s6e63m0_spi_probe(struct spi_device *spi) 70 { 71 struct device *dev = &spi->dev; 72 int ret; 73 74 spi->bits_per_word = 9; 75 /* Preserve e.g. SPI_3WIRE setting */ 76 spi->mode |= SPI_MODE_3; 77 ret = spi_setup(spi); 78 if (ret < 0) { 79 dev_err(dev, "spi setup failed.\n"); 80 return ret; 81 } 82 return s6e63m0_probe(dev, s6e63m0_spi_dcs_read, s6e63m0_spi_dcs_write, 83 false); 84 } 85 86 static int s6e63m0_spi_remove(struct spi_device *spi) 87 { 88 return s6e63m0_remove(&spi->dev); 89 } 90 91 static const struct of_device_id s6e63m0_spi_of_match[] = { 92 { .compatible = "samsung,s6e63m0" }, 93 { /* sentinel */ } 94 }; 95 MODULE_DEVICE_TABLE(of, s6e63m0_spi_of_match); 96 97 static struct spi_driver s6e63m0_spi_driver = { 98 .probe = s6e63m0_spi_probe, 99 .remove = s6e63m0_spi_remove, 100 .driver = { 101 .name = "panel-samsung-s6e63m0", 102 .of_match_table = s6e63m0_spi_of_match, 103 }, 104 }; 105 module_spi_driver(s6e63m0_spi_driver); 106 107 MODULE_AUTHOR("Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>"); 108 MODULE_DESCRIPTION("s6e63m0 LCD SPI Driver"); 109 MODULE_LICENSE("GPL v2"); 110