17.09.2020 14:38, Thierry Reding пишет: > On Wed, Sep 09, 2020 at 01:39:44AM +0300, Dmitry Osipenko wrote: >> Use clk-bulk helpers and factor out clocks initialization into separate >> function in order to make code cleaner. >> >> The clocks initialization now performed after reset-control initialization >> in order to avoid a noisy -PROBE_DEFER errors on T186+ from the clk-bulk >> helper which doesn't silence this error code. Hence reset_control_get() >> now may return -EPROBE_DEFER on newer Tegra SoCs because they use BPMP >> driver that provides reset controls and BPMP doesn't come up early during >> boot. Previously rst was protected by the clocks retrieval and now this >> patch makes dev_err_probe() to be used for the rst error handling. >> >> Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> >> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> >> --- >> drivers/i2c/busses/i2c-tegra.c | 187 ++++++++++++--------------------- >> 1 file changed, 67 insertions(+), 120 deletions(-) > > This is tempting from a diffstat point of view, but the downside is that > we can now no longer validate that all of the necessary clocks are given > in device tree. > > Previously the driver would fail to probe the I2C controller if any of > the expected clocks were not defined in device tree, but now it's just > going to continue without it and not give any indication as to what's > wrong. The clocks can't be missed randomly in a device-tree because they are a part of the core tegra.dtsi The tegra-i2c DT binding isn't converted to YAML, but once it will be, then the dtbs_check will tell you about such obvious problems like a missing mandatory property. Even if clock is missing, then you won't miss this problem since I2C shouldn't work in that case. There is a Qualcomm I2C driver that already uses clk_bulk_get_all() and doesn't worry about "accidentally" missing clocks. It's still possible to add the clk-num checking, but it should be unpractical. We could always add it later on if there will be a real incident. Do you agree?
