Commit b6789320 authored Jun 28, 2015 by Milo Kim Committed by Bryan Wu Jun 29, 2015

leds:lp55xx: fix firmware loading error



LP55xx driver uses not firmware file but raw data to load program through
the firmware interface.(Documents/leds/leds-lp55xx.txt)

  For example, here is how to run blinking green channel pattern.
  (The second engine is seleted and MUX is mapped to 'RGB' mode)
  echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
  echo "RGB" > /sys/bus/i2c/devices/xxxx/engine_mux
  echo 1 > /sys/class/firmware/lp5562/loading
  echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
  echo 0 > /sys/class/firmware/lp5562/loading
  echo 1 > /sys/bus/i2c/devices/xxxx/run_engine

However, '/sys/class/firmware/<device name>' is not created after the
firmware loader user helper was introduced.
This feature is used in the case below.

  As soon as the firmware download is requested by the driver, firmware
  class subsystem tries to find the binary file.
  If it gets failed, then it just falls back to user helper to load
  raw data manually. Here, you can see the device file under
  /sys/class/firmware/.

To make it happen, LP55xx driver requires two configurations.

  1. Enable CONFIG_FW_LOADER_USER_HELPER_FALLBACK in Kconfig
  2. Set option, 'FW_OPT_USERHELPER' on requesting the firmware data.
     It means the second option should be 'false' in
     request_firmware_nowait().
     This option enables to load firmware data manually by calling
     fw_load_from_user_helper().

Cc: linux-leds@vger.kernel.org
Signed-off-by: Milo Kim <milo.kim@ti.com>
Acked-by: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

parent 10c19c9e

drivers/leds/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -232,6 +232,7 @@ config LEDS_LP55XX_COMMON
		tristate "Common Driver for TI/National LP5521/5523/55231/5562/8501"
		depends on LEDS_LP5521 \|\| LEDS_LP5523 \|\| LEDS_LP5562 \|\| LEDS_LP8501
		select FW_LOADER
		select FW_LOADER_USER_HELPER_FALLBACK
		help
		This option supports common operations for LP5521/5523/55231/5562/8501
		devices.

drivers/leds/leds-lp55xx-common.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -223,7 +223,7 @@ static int lp55xx_request_firmware(struct lp55xx_chip *chip)
		const char *name = chip->cl->name;
		struct device *dev = &chip->cl->dev;

		return request_firmware_nowait(THIS_MODULE, true, name, dev,
		return request_firmware_nowait(THIS_MODULE, false, name, dev,
		GFP_KERNEL, chip, lp55xx_firmware_loaded);
		}

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