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         /*
  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");