kernel/drivers/nvmem/core.c, branch linux-4.17.y

nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us

2018-08-24T11:07:02Z

[ Upstream commit 87ed1405ef09d29a14df43295f7b6a93b63bfe6e ] In commit ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") you can see a call like: devm_nvmem_cell_get(dev, NULL); Note that the cell ID passed to the function is NULL. This is because the qcom-qusb2 driver is expected to work only on systems where the PHY node is hooked up via device-tree and is nameless. This works OK for the most part. The first thing nvmem_cell_get() does is to call of_nvmem_cell_get() and there it's documented that a NULL name is fine. The problem happens when the call to of_nvmem_cell_get() returns -EINVAL. In such a case we'll fall back to nvmem_cell_get_from_list() and eventually might (if nvmem_cells isn't an empty list) crash with something that looks like: strcmp nvmem_find_cell __nvmem_device_get nvmem_cell_get_from_list nvmem_cell_get devm_nvmem_cell_get qusb2_phy_probe There are several different ways we could fix this problem: One could argue that perhaps the qcom-qusb2 driver should be changed to use of_nvmem_cell_get() which is allowed to have a NULL name. In that case, we'd need to add a patche to introduce devm_of_nvmem_cell_get() since the qcom-qusb2 driver is using devm managed resources. One could also argue that perhaps we could just add a name to qcom-qusb2. That would be OK but I believe it effectively changes the device tree bindings, so maybe it's a no-go. In this patch I have chosen to fix the problem by simply not crashing when a NULL cell_id is passed to nvmem_cell_get(). NOTE: that for the qcom-qusb2 driver the "nvmem-cells" property is defined to be optional and thus it's expected to be a common case that we would hit this crash and this is more than just a theoretical fix. Fixes: ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") Signed-off-by: Douglas Anderson Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvmem: properly handle returned value nvmem_reg_read

2018-08-03T05:47:52Z

[ Upstream commit 50808bfcc14b854775a9f1d0abe3dac2babcf5c3 ] Function nvmem_reg_read can return a non zero value indicating an error. This returned value must be read and error propagated to nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1): drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but not used [-Wunused-but-set-variable] Signed-off-by: Mathieu Malaterre Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nvmem: Introduce devm_nvmem_(un)register()

2018-03-14T18:28:13Z

Introduce devm_nvmem_register()/devm_nvmem_unregister() to make .remove() unnecessary in trivial drivers. Cc: Srinivas Kandagatla Cc: Heiko Stuebner Cc: Masahiro Yamada Cc: Carlo Caione Cc: Kevin Hilman Cc: Matthias Brugger Cc: cphealy@gmail.com Cc: linux-kernel@vger.kernel.org Cc: linux-mediatek@lists.infradead.org Cc: linux-rockchip@lists.infradead.org Cc: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Andrey Smirnov Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: Allow specifying device name verbatim

2018-03-14T18:28:13Z

Add code to allow avoid having nvmem core append a numeric suffix to the end of the name by passing config->id of -1. Cc: Srinivas Kandagatla Cc: Heiko Stuebner Cc: Masahiro Yamada Cc: Carlo Caione Cc: Kevin Hilman Cc: Matthias Brugger Cc: cphealy@gmail.com Cc: linux-kernel@vger.kernel.org Cc: linux-mediatek@lists.infradead.org Cc: linux-rockchip@lists.infradead.org Cc: linux-amlogic@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Andrey Smirnov Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: switch to device_property_present for reading property "read-only"

2017-12-19T09:39:33Z

Switch to more generic device_property_present to consider also non-DT properties. Signed-off-by: Heiner Kallweit Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: let stride and word_size default to 1

2017-12-19T09:39:33Z

If the caller doesn't set stride and/or word_size in struct nvmem_config then nvmem_register accepts this but we may face strange effects later due to both values being 0. Therefore use 1 as default for both values. Signed-off-by: Heiner Kallweit Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: core: Deduplicate bus_find_device() by name matching

2017-12-19T09:39:33Z

No need to reinvent the wheel, we have bus_find_device_by_name(). Signed-off-by: Lukas Wunner Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

nvmem: set nvmem->owner to nvmem->dev->driver->owner if unset

2017-11-08T12:54:17Z

All nvmem drivers are supposed to set the owner field of struct nvmem_config, but this matches nvmem->dev->driver->owner. As far as I see in drivers/nvmem/ directory, all the drivers are the case. So, make nvmem_register() set the nvmem's owner to the associated driver's owner unless nvmem_config sets otherwise. Remove .owner settings in the drivers that are now redundant. Signed-off-by: Masahiro Yamada Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman

Merge 4.14-rc5 into char-misc-next

2017-10-16T07:22:22Z

We need the fixes in here to resolve merge issues and for testing. Signed-off-by: Greg Kroah-Hartman

nvmem: remove unneeded IS_ENABLED(CONFIG_NVMEM) conditional

2017-09-18T14:20:26Z

As you see in drivers/nvmem/Makefile, this C file is compiled only when CONFIG_NVMEM is y or m. So, IS_ENABLED(CONFIG_NVMEM) is always evaluated to 1 in this file. Signed-off-by: Masahiro Yamada Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman