kernel/linux.git/drivers/input/touchscreen/ads7846.c, branch v7.2-rc2

Input: ads7846 - don't use scratch for tx_buf when clearing register

2026-06-10T22:47:47+00:00

The workaround for XPT2046 clears the command register, giving the touchscreen controller a NOP. The change incorrectly re-uses the req->scratch variable which is used as rx_buf for xfer[5], so by the time xfer[6] occurs, the contents of req->scratch may not be 0. It was found that the touchscreen controller can end up in a completely unresponsive state due to it being given a command the driver does not expect. Instead, rely on the spi_transfer behavior of tx_buf being NULL to transmit all 0 bits and use the scratch variable for the rx_buf for both the 1 byte command to and 2 byte response from the controller. Also relocates the scratch member of struct ser_req to force it into a different cache line to prevent any potential issues of DMA stepping on unrelated data in other struct members due to sharing the same cache line. This change was tested on real TSC2046 and ADS7843 controllers, but not the XPT2046 the workaround was originally created for. Confirming that the original modification to clear the command register does not impact either real controller. Fixes: 781a07da9bb94 ("Input: ads7846 - add dummy command register clearing cycle") Cc: stable@vger.kernel.org Co-developed-by: Mark Featherston Signed-off-by: Mark Featherston Signed-off-by: Kris Bahnsen Link: https://patch.msgid.link/20260507164943.760009-1-kris@embeddedTS.com Signed-off-by: Dmitry Torokhov

Input: ads7846 - restore half-duplex support

2026-06-10T18:31:29+00:00

On some boards, the SPI controller is limited to half-duplex and the driver fails spamming "ads7846 spi2.1: spi_sync --> -22". Restore half-duplex support with multiple SPI transfers. Fixes: 9c9509717b53 ("Input: ads7846 - convert to full duplex") Signed-off-by: Aaro Koskinen Link: https://patch.msgid.link/20260419161848.825831-2-aaro.koskinen@iki.fi Signed-off-by: Dmitry Torokhov

Input: ads7846 - switch to using cleanup functions

2026-03-25T04:14:20+00:00

Start using __free() and guard() primitives to simplify the code and error handling. Signed-off-by: Dmitry Torokhov

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

Input: ads7846 - fix gpiod allocation

2025-02-03T12:37:57+00:00

commit 767d83361aaa ("Input: ads7846 - Convert to use software nodes") has simplified the code but accidentially converted a devm_gpiod_get() to gpiod_get(). This leaves the gpio reserved on module remove and the driver can no longer be loaded again. Fixes: 767d83361aaa ("Input: ads7846 - Convert to use software nodes") Cc: stable@vger.kernel.org Signed-off-by: H. Nikolaus Schaller Link: https://lore.kernel.org/r/6e9b143f19cdfda835711a8a7a3966e5a2494cff.1738410204.git.hns@goldelico.com Signed-off-by: Dmitry Torokhov

Merge tag 'input-for-v6.13-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

2024-11-25T18:31:39+00:00

Pull input updates from Dmitry Torokhov: - support for NT36672A touchscreen added to novatek-nvt-ts driver - a change to ads7846 driver to prevent XPT2046 from locking up - a change switching platform input dirves back to using remove() method (from remove_new()) - updates to a number of input drivers to use the new cleanup facilities (__free(...), guard(), and scoped-guard()) which ensure that the resources and locks are released properly and automatically - other assorted driver cleanups and fixes. * tag 'input-for-v6.13-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: (109 commits) Input: mpr121 - use devm_regulator_get_enable_read_voltage() Input: sun4i-lradc-keys - don't include 'pm_wakeup.h' directly Input: spear-keyboard - don't include 'pm_wakeup.h' directly Input: cypress-sf - constify struct i2c_device_id Input: ads7846 - increase xfer array size in 'struct ser_req' Input: fix the input_event struct documentation Input: i8042 - fix typo dublicate to duplicate Input: ads7846 - add dummy command register clearing cycle Input: cs40l50 - fix wrong usage of INIT_WORK() Input: introduce notion of passive observers for input handlers Input: maple_keyb - use guard notation when acquiring mutex Input: locomokbd - use guard notation when acquiring spinlock Input: hilkbd - use guard notation when acquiring spinlock Input: synaptics-rmi4 - switch to using cleanup functions in F34 Input: synaptics - fix a typo dt-bindings: input: rotary-encoder: Fix "rotary-encoder,rollover" type Input: omap-keypad - use guard notation when acquiring mutex Input: imagis - fix warning regarding 'imagis_3038_data' being unused Input: userio - remove unneeded semicolon Input: sparcspkr - use cleanup facility for device_node ...

Input: ads7846 - increase xfer array size in 'struct ser_req'

2024-11-15T02:04:52+00:00

Clang warns (or errors with CONFIG_WERROR=y, trimmed for brevity): drivers/input/touchscreen/ads7846.c:412:2: error: array index 6 is past the end of the array (that has type 'struct spi_transfer[6]') [-Werror,-Warray-bounds] 412 | req->xfer[6].tx_buf = &req->scratch; | ^ ~ ... drivers/input/touchscreen/ads7846.c:416:2: error: array index 7 is past the end of the array (that has type 'struct spi_transfer[6]') [-Werror,-Warray-bounds] 416 | req->xfer[7].rx_buf = &req->scratch; | ^ ~ drivers/input/touchscreen/ads7846.c:334:2: note: array 'xfer' declared here 334 | struct spi_transfer xfer[6]; | ^ Increase the size of xfer in 'struct ser_req' to ensure that there is enough space for all necessary members and there are no out of bounds accesses, clearing up the warning. Fixes: 781a07da9bb9 ("Input: ads7846 - add dummy command register clearing cycle") Signed-off-by: Nathan Chancellor Reviewed-by: Marek Vasut Link: https://lore.kernel.org/r/20241111-input-ads7846-increase-xfer-array-size-v1-1-06cd92e9f20f@kernel.org Signed-off-by: Dmitry Torokhov

Input: ads7846 - add dummy command register clearing cycle

2024-11-08T05:59:13+00:00

On STM32MP135F with XPT2046 touch controller attached to SPI bus, it has been observed that the touch controller locks up after Linux kernel has finished booting. Adding a dummy cycle on the SPI bus seems to mitigate the lock up. The XPTEK XPT2046 controller seems to be an identical clone of TI TSC2046, the datasheet seems to be a clone of the TI part as well, text seem to be word to word identical, except all the pictures have been drawn again. This touch controller is present e.g. on WaveShare 3.2inch RPi LCD (B) panel, the DTO provided by WaveShare uses 50 kHz SPI clock for this touch controller, which is unusually low and possibly might have been used as some sort of workaround for an issue. The SPI LCD on the same bus uses 16 MHz clock. SPI bus DT properties spi-cs-setup-delay-ns, spi-cs-hold-delay-ns, spi-cs-inactive-delay-ns, spi-rx-delay-us, spi-tx-delay-us set to range of 500ns..5us seem to have no impact on the behavior of the touch controller, the lock up always occurs. The STM32MP13xx SPI controller users GPIO control for the nCS pins. Since the dummy cycle happens after the controller has been put into power down mode and both ADC and REF regulators have been disabled, the cycle should have no impact on the configuration of the controller, i.e. it should be a NOP. It is unclear whether this problem is specific to this cloned XPT2046 controller, or whether this is also present on TSC2046. A test on either TSC2046 or ADS7846 would be very welcome. Signed-off-by: Marek Vasut Link: https://lore.kernel.org/r/20240320072533.170029-1-marex@denx.de Signed-off-by: Dmitry Torokhov

move asm/unaligned.h to linux/unaligned.h

2024-10-02T21:23:23+00:00

asm/unaligned.h is always an include of asm-generic/unaligned.h; might as well move that thing to linux/unaligned.h and include that - there's nothing arch-specific in that header. auto-generated by the following: for i in `git grep -l -w asm/unaligned.h`; do sed -i -e "s/asm\/unaligned.h/linux\/unaligned.h/" $i done for i in `git grep -l -w asm-generic/unaligned.h`; do sed -i -e "s/asm-generic\/unaligned.h/linux\/unaligned.h/" $i done git mv include/asm-generic/unaligned.h include/linux/unaligned.h git mv tools/include/asm-generic/unaligned.h tools/include/linux/unaligned.h sed -i -e "/unaligned.h/d" include/asm-generic/Kbuild sed -i -e "s/__ASM_GENERIC/__LINUX/" include/linux/unaligned.h tools/include/linux/unaligned.h