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3fd14cdcc0
Core:
* Remove support for asynchronous erase (not implemented by any of
the existing drivers anyway)
* Remove Cyrille from the list of SPI NOR and MTD maintainers
* Fix kernel doc headers
* Allow users to define the partitions parsers they want to test
through a DT property (compatible of the partitions subnode)
* Remove the bfin-async-flash driver (the only architecture using
it has been removed)
* Fix pagetest test
* Add extra checks in mtd_erase()
* Simplify the MTD partition creation logic and get rid of
mtd_add_device_partitions()
Drivers:
* Add endianness information to the physmap DT binding
* Add Eon EN29LV400A IDs to JEDEC probe logic
* Use %*ph where appropriate
SPI NOR changes:
Drivers:
* Make fsl-quaspi assign different names to MTD devices connected
to the same QSPI controller
* Remove an unneeded driver.bus assigned in the fsl-qspi driver
NAND changes:
Core:
* Prepare arrival of the SPI NAND subsystem by implementing a
generic (interface-agnostic) layer to ease manipulation of NAND
devices
* Move onenand code base to the drivers/mtd/nand/ dir
* Rework timing mode selection
* Provide a generic way for NAND chip drivers to flag a specific
GET/SET FEATURE operation as supported/unsupported
* Stop embedding ONFI/JEDEC param page in nand_chip
Drivers:
* Rework/cleanup of the mxc driver
* Various cleanups in the vf610 driver
* Migrate the fsmc and vf610 to ->exec_op()
* Get rid of the pxa driver (replaced by marvell_nand)
* Support ->setup_data_interface() in the GPMI driver
* Fix probe error path in several drivers
* Remove support for unused hw_syndrome mode in sunxi_nand
* Various minor improvements
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Merge tag 'mtd/for-4.17' of git://git.infradead.org/linux-mtd
Pull MTD updates from Boris Brezillon:
"MTD Core:
- Remove support for asynchronous erase (not implemented by any of
the existing drivers anyway)
- Remove Cyrille from the list of SPI NOR and MTD maintainers
- Fix kernel doc headers
- Allow users to define the partitions parsers they want to test
through a DT property (compatible of the partitions subnode)
- Remove the bfin-async-flash driver (the only architecture using it
has been removed)
- Fix pagetest test
- Add extra checks in mtd_erase()
- Simplify the MTD partition creation logic and get rid of
mtd_add_device_partitions()
MTD Drivers:
- Add endianness information to the physmap DT binding
- Add Eon EN29LV400A IDs to JEDEC probe logic
- Use %*ph where appropriate
SPI NOR Drivers:
- Make fsl-quaspi assign different names to MTD devices connected to
the same QSPI controller
- Remove an unneeded driver.bus assigned in the fsl-qspi driver
NAND Core:
- Prepare arrival of the SPI NAND subsystem by implementing a generic
(interface-agnostic) layer to ease manipulation of NAND devices
- Move onenand code base to the drivers/mtd/nand/ dir
- Rework timing mode selection
- Provide a generic way for NAND chip drivers to flag a specific
GET/SET FEATURE operation as supported/unsupported
- Stop embedding ONFI/JEDEC param page in nand_chip
NAND Drivers:
- Rework/cleanup of the mxc driver
- Various cleanups in the vf610 driver
- Migrate the fsmc and vf610 to ->exec_op()
- Get rid of the pxa driver (replaced by marvell_nand)
- Support ->setup_data_interface() in the GPMI driver
- Fix probe error path in several drivers
- Remove support for unused hw_syndrome mode in sunxi_nand
- Various minor improvements"
* tag 'mtd/for-4.17' of git://git.infradead.org/linux-mtd: (89 commits)
dt-bindings: fsl-quadspi: Add the example of two SPI NOR
mtd: fsl-quadspi: Distinguish the mtd device names
mtd: nand: Fix some function description mismatches in core.c
mtd: fsl-quadspi: Remove unneeded driver.bus assignment
mtd: rawnand: marvell: Rename ->ecc_clk into ->core_clk
mtd: rawnand: s3c2410: enhance the probe function error path
mtd: rawnand: tango: fix probe function error path
mtd: rawnand: sh_flctl: fix the probe function error path
mtd: rawnand: omap2: fix the probe function error path
mtd: rawnand: mxc: fix probe function error path
mtd: rawnand: denali: fix probe function error path
mtd: rawnand: davinci: fix probe function error path
mtd: rawnand: cafe: fix probe function error path
mtd: rawnand: brcmnand: fix probe function error path
mtd: rawnand: sunxi: Stop supporting ECC_HW_SYNDROME mode
mtd: rawnand: marvell: Fix clock resource by adding a register clock
mtd: ftl: Use DIV_ROUND_UP()
mtd: Fix some function description mismatches in mtdcore.c
mtd: physmap_of: update struct map_info's swap as per map requirement
dt-bindings: mtd-physmap: Add endianness supports
...
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============================
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Subsystem drivers using GPIO
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============================
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Note that standard kernel drivers exist for common GPIO tasks and will provide
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the right in-kernel and userspace APIs/ABIs for the job, and that these
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drivers can quite easily interconnect with other kernel subsystems using
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hardware descriptions such as device tree or ACPI:
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- leds-gpio: drivers/leds/leds-gpio.c will handle LEDs connected to GPIO
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lines, giving you the LED sysfs interface
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- ledtrig-gpio: drivers/leds/trigger/ledtrig-gpio.c will provide a LED trigger,
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i.e. a LED will turn on/off in response to a GPIO line going high or low
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(and that LED may in turn use the leds-gpio as per above).
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- gpio-keys: drivers/input/keyboard/gpio_keys.c is used when your GPIO line
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can generate interrupts in response to a key press. Also supports debounce.
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- gpio-keys-polled: drivers/input/keyboard/gpio_keys_polled.c is used when your
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GPIO line cannot generate interrupts, so it needs to be periodically polled
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by a timer.
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- gpio_mouse: drivers/input/mouse/gpio_mouse.c is used to provide a mouse with
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up to three buttons by simply using GPIOs and no mouse port. You can cut the
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mouse cable and connect the wires to GPIO lines or solder a mouse connector
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to the lines for a more permanent solution of this type.
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- gpio-beeper: drivers/input/misc/gpio-beeper.c is used to provide a beep from
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an external speaker connected to a GPIO line.
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- extcon-gpio: drivers/extcon/extcon-gpio.c is used when you need to read an
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external connector status, such as a headset line for an audio driver or an
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HDMI connector. It will provide a better userspace sysfs interface than GPIO.
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- restart-gpio: drivers/power/reset/gpio-restart.c is used to restart/reboot
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the system by pulling a GPIO line and will register a restart handler so
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userspace can issue the right system call to restart the system.
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- poweroff-gpio: drivers/power/reset/gpio-poweroff.c is used to power the
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system down by pulling a GPIO line and will register a pm_power_off()
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callback so that userspace can issue the right system call to power down the
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system.
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- gpio-gate-clock: drivers/clk/clk-gpio.c is used to control a gated clock
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(off/on) that uses a GPIO, and integrated with the clock subsystem.
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- i2c-gpio: drivers/i2c/busses/i2c-gpio.c is used to drive an I2C bus
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(two wires, SDA and SCL lines) by hammering (bitbang) two GPIO lines. It will
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appear as any other I2C bus to the system and makes it possible to connect
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drivers for the I2C devices on the bus like any other I2C bus driver.
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- spi_gpio: drivers/spi/spi-gpio.c is used to drive an SPI bus (variable number
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of wires, at least SCK and optionally MISO, MOSI and chip select lines) using
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GPIO hammering (bitbang). It will appear as any other SPI bus on the system
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and makes it possible to connect drivers for SPI devices on the bus like
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any other SPI bus driver. For example any MMC/SD card can then be connected
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to this SPI by using the mmc_spi host from the MMC/SD card subsystem.
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- w1-gpio: drivers/w1/masters/w1-gpio.c is used to drive a one-wire bus using
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a GPIO line, integrating with the W1 subsystem and handling devices on
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the bus like any other W1 device.
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- gpio-fan: drivers/hwmon/gpio-fan.c is used to control a fan for cooling the
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system, connected to a GPIO line (and optionally a GPIO alarm line),
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presenting all the right in-kernel and sysfs interfaces to make your system
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not overheat.
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- gpio-regulator: drivers/regulator/gpio-regulator.c is used to control a
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regulator providing a certain voltage by pulling a GPIO line, integrating
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with the regulator subsystem and giving you all the right interfaces.
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- gpio-wdt: drivers/watchdog/gpio_wdt.c is used to provide a watchdog timer
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that will periodically "ping" a hardware connected to a GPIO line by toggling
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it from 1-to-0-to-1. If that hardware does not receive its "ping"
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periodically, it will reset the system.
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- gpio-nand: drivers/mtd/nand/raw/gpio.c is used to connect a NAND flash chip
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to a set of simple GPIO lines: RDY, NCE, ALE, CLE, NWP. It interacts with the
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NAND flash MTD subsystem and provides chip access and partition parsing like
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any other NAND driving hardware.
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- ps2-gpio: drivers/input/serio/ps2-gpio.c is used to drive a PS/2 (IBM) serio
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bus, data and clock line, by bit banging two GPIO lines. It will appear as
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any other serio bus to the system and makes it possible to connect drivers
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for e.g. keyboards and other PS/2 protocol based devices.
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Apart from this there are special GPIO drivers in subsystems like MMC/SD to
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read card detect and write protect GPIO lines, and in the TTY serial subsystem
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to emulate MCTRL (modem control) signals CTS/RTS by using two GPIO lines. The
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MTD NOR flash has add-ons for extra GPIO lines too, though the address bus is
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usually connected directly to the flash.
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Use those instead of talking directly to the GPIOs using sysfs; they integrate
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with kernel frameworks better than your userspace code could. Needless to say,
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just using the appropriate kernel drivers will simplify and speed up your
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embedded hacking in particular by providing ready-made components.
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