From: Lee Jones lee.jones@linaro.org
[ Upstream commit b195e101580db390f50b0d587b7f66f241d2bc88 ]
If a child device calls mfd_cell_{en,dis}able() without an appropriate call-back being set, we are likely to encounter a panic. Avoid this by adding suitable checking.
Signed-off-by: Lee Jones lee.jones@linaro.org Reviewed-by: Daniel Thompson daniel.thompson@linaro.org Reviewed-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mfd/mfd-core.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 23276a80e3b48..96d02b6f06fd8 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -28,6 +28,11 @@ int mfd_cell_enable(struct platform_device *pdev) const struct mfd_cell *cell = mfd_get_cell(pdev); int err = 0;
+ if (!cell->enable) { + dev_dbg(&pdev->dev, "No .enable() call-back registered\n"); + return 0; + } + /* only call enable hook if the cell wasn't previously enabled */ if (atomic_inc_return(cell->usage_count) == 1) err = cell->enable(pdev); @@ -45,6 +50,11 @@ int mfd_cell_disable(struct platform_device *pdev) const struct mfd_cell *cell = mfd_get_cell(pdev); int err = 0;
+ if (!cell->disable) { + dev_dbg(&pdev->dev, "No .disable() call-back registered\n"); + return 0; + } + /* only disable if no other clients are using it */ if (atomic_dec_return(cell->usage_count) == 0) err = cell->disable(pdev);