drivers/gpu/drm/panel/panel-samsung-s6e63m0-spi.c

   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");