[PATCH 1/3] drm/mipi-dbi: Add support for Type B

[kernel test robot]

Hi,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linux/master]
[also build test WARNING on robh/for-next drm-intel/for-linux-next drm-exynos/exynos-drm-next tegra-drm/drm/tegra/for-next linus/master v5.10-rc4 next-20201118]
[cannot apply to drm/drm-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/mdurnev-gmail-com/drm-mipi-dbi-Type-B-bus-support-drm-tiny-MRB2801/20201118-153901
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 09162bc32c880a791c6c0668ce0745cf7958f576
config: alpha-randconfig-s032-20201118 (attached as .config)
compiler: alpha-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-107-gaf3512a6-dirty
        # https://github.com/0day-ci/linux/commit/f75093067b26ff68b2de896f317a03a10d8bc7ff
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review mdurnev-gmail-com/drm-mipi-dbi-Type-B-bus-support-drm-tiny-MRB2801/20201118-153901
        git checkout f75093067b26ff68b2de896f317a03a10d8bc7ff
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=alpha 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>


"sparse warnings: (new ones prefixed by >>)"
>> drivers/gpu/drm/drm_mipi_dbi.c:1255:20: sparse: sparse: Using plain integer as NULL pointer

vim +1255 drivers/gpu/drm/drm_mipi_dbi.c

  1234	
  1235	/**
  1236	 * mipi_dbi_gpio_init - Initialize MIPI DBI Type B interface implemented via GPIO
  1237	 * @dbi: MIPI DBI structure to initialize
  1238	 * @dc: D/C gpio
  1239	 * @wr: W/R gpio
  1240	 * @db: DB gpios
  1241	 * @wr_up_delay: Delay after setting DB and before changing W/R from low to high
  1242	 * @wr_down_delay: Delay after changing W/R from low to high
  1243	 *
  1244	 * This function sets &mipi_dbi->command, enables &mipi_dbi->read_commands for the
  1245	 * usual read commands. It should be followed by a call to mipi_dbi_dev_init() or
  1246	 * a driver-specific init.
  1247	 *
  1248	 * Returns:
  1249	 * Zero on success, negative error code on failure.
  1250	 */
  1251	int mipi_dbi_gpio_init(struct mipi_dbi *dbi, struct gpio_desc *dc,
  1252			      struct gpio_desc *wr, struct gpio_descs *db,
  1253			      unsigned long wr_up_delay, unsigned long wr_down_delay)
  1254	{
> 1255		dbi->spi = 0; /* Type B uses GPIO lines rather than SPI */
  1256	
  1257		dbi->read_commands = mipi_dbi_dcs_read_commands;
  1258		dbi->command = mipi_dbi_gpio_command;
  1259	
  1260		dbi->dc = dc;
  1261		dbi->wr = wr;
  1262		dbi->db = db;
  1263		dbi->wr_up_delay = wr_up_delay;
  1264		dbi->wr_down_delay = wr_down_delay;
  1265	
  1266		if (mipi_dbi_machine_little_endian())
  1267			dbi->swap_bytes = true;
  1268	
  1269		mutex_init(&dbi->cmdlock);
  1270	
  1271		return 0;
  1272	}
  1273	EXPORT_SYMBOL(mipi_dbi_gpio_init);
  1274	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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