kernel/linux.git/drivers/mfd/syscon.c, branch v6.6.132

mfd: syscon: Fix race in device_node_get_regmap()

2025-02-08T08:51:57+00:00

[ Upstream commit 805f7aaf7fee14a57b56af01d270edf6c10765e8 ] It is possible for multiple, simultaneous callers calling device_node_get_regmap() with the same node to fail to find an entry in the syscon_list. There is a period of time while the first caller is calling of_syscon_register() that subsequent callers also fail to find an entry in the syscon_list and then call of_syscon_register() a second time. Fix this by keeping the lock held until after of_syscon_register() completes and adds the node to syscon_list. Convert the spinlock to a mutex as many of the functions called in of_syscon_register() such as kzalloc() and of_clk_get() may sleep. Fixes: bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform devices") Signed-off-by: Rob Herring (Arm) Reviewed-by: Krzysztof Kozlowski Tested-by: Krzysztof Kozlowski Tested-by: Will McVicker Tested-by: Pankaj Dubey Reviewed-by: Pankaj Dubey Link: https://lore.kernel.org/r/20241217-syscon-fixes-v2-1-4f56d750541d@kernel.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

mfd: syscon: Use scoped variables with memory allocators to simplify error paths

2025-02-08T08:51:57+00:00

[ Upstream commit 82f898f47112bc7b787cb9ce8803c4e2f9f60c89 ] Allocate the memory with scoped/cleanup.h to reduce error handling and make the code a bit simpler. Signed-off-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20240707114823.9175-2-krzysztof.kozlowski@linaro.org Signed-off-by: Lee Jones Stable-dep-of: 805f7aaf7fee ("mfd: syscon: Fix race in device_node_get_regmap()") Signed-off-by: Sasha Levin

mfd: syscon: Add of_syscon_register_regmap() API

2025-02-08T08:51:57+00:00

[ Upstream commit 769cb63166d90f1fadafa4352f180cbd96b6cb77 ] The of_syscon_register_regmap() API allows an externally created regmap to be registered with syscon. This regmap can then be returned to client drivers using the syscon_regmap_lookup_by_phandle() APIs. The API is used by platforms where mmio access to the syscon registers is not possible, and a underlying soc driver like exynos-pmu provides a SoC specific regmap that can issue a SMC or hypervisor call to write the register. This approach keeps the SoC complexities out of syscon, but allows common drivers such as syscon-poweroff, syscon-reboot and friends that are used by many SoCs already to be re-used. Signed-off-by: Peter Griffin Reviewed-by: Arnd Bergmann Reviewed-by: Sam Protsenko Tested-by: Will McVicker Reviewed-by: Krzysztof Kozlowski Link: https://lore.kernel.org/r/20240621115544.1655458-2-peter.griffin@linaro.org Signed-off-by: Lee Jones Stable-dep-of: 805f7aaf7fee ("mfd: syscon: Fix race in device_node_get_regmap()") Signed-off-by: Sasha Levin

mfd: syscon: Call of_node_put() only when of_parse_phandle() takes a ref

2024-03-26T22:19:51+00:00

[ Upstream commit d2b0680cf3b05490b579e71b0df6e07451977745 ] of_parse_phandle() returns a device_node with refcount incremented, which the callee needs to call of_node_put() on when done. We should only call of_node_put() when the property argument is provided though as otherwise nothing has taken a reference on the node. Fixes: 45330bb43421 ("mfd: syscon: Allow property as NULL in syscon_regmap_lookup_by_phandle") Signed-off-by: Peter Griffin Link: https://lore.kernel.org/r/20240220115012.471689-2-peter.griffin@linaro.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

mfd: syscon: Fix null pointer dereference in of_syscon_register()

2024-01-25T23:35:49+00:00

[ Upstream commit 41673c66b3d0c09915698fec5c13b24336f18dd1 ] kasprintf() returns a pointer to dynamically allocated memory which can be NULL upon failure. Fixes: e15d7f2b81d2 ("mfd: syscon: Use a unique name with regmap_config") Signed-off-by: Kunwu Chan Reviewed-by: Arnd Bergmann Link: https://lore.kernel.org/r/20231204092443.2462115-1-chentao@kylinos.cn Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

mfd: syscon: Allow reset control for syscon devices

2023-02-22T08:25:53+00:00

Simple syscon devices may require deassertion of a reset signal in order to access their register set. Rather than requiring a custom driver to implement this, we can use the generic "resets" specifiers to link a reset line to the syscon. This change adds an optional reset line to the syscon device description, and deasserts the reset if detected. Signed-off-by: Jeremy Kerr Reviewed-by: Arnd Bergmann Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20230105005010.124948-3-jk@codeconstruct.com.au

Revert "mfd: syscon: Remove repetition of the regmap_get_val_endian()"

2022-10-23T19:04:56+00:00

This reverts commit 72a95859728a7866522e6633818bebc1c2519b17. It broke reboots on big-endian MIPS and MIPS64 malta QEMU instances, which use the syscon driver. Little-endian is not effected, which means likely it's important to handle regmap_get_val_endian() in this function after all. Fixes: 72a95859728a ("mfd: syscon: Remove repetition of the regmap_get_val_endian()") Reviewed-by: Andy Shevchenko Cc: Lee Jones Signed-off-by: Jason A. Donenfeld Signed-off-by: Linus Torvalds

mfd: syscon: Remove repetition of the regmap_get_val_endian()

2022-09-29T18:06:57+00:00

Since the commit 0dbdb76c0ca8 ("regmap: mmio: Parse endianness definitions from DT") regmap MMIO parses DT itsef, no need to repeat this in the caller(s). Signed-off-by: Andy Shevchenko Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20220808140811.26734-1-andriy.shevchenko@linux.intel.com

syscon: Use %pa to format the variable of resource_size_t type

2022-07-19T09:54:39+00:00

Instead of explicit casting, use %pa specifier to format the variable of resource_size_t type. Signed-off-by: Andy Shevchenko Acked-by: Arnd Bergmann Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20220531202404.70282-1-andriy.shevchenko@linux.intel.com

mfd: syscon: Use of_iomap() instead of ioremap()

2021-09-07T07:34:08+00:00

This automatically selects between ioremap() and ioremap_np() on platforms that require it, such as Apple SoCs. Signed-off-by: Hector Martin Acked-by: Arnd Bergmann Signed-off-by: Lee Jones