On 04/08, Masahiro Yamada wrote: > > > This makes our driver programming life easier. > > > For example, let's see drivers/tty/serial/8250/8250_of.c > > > The "clock-frequency" DT property takes precedence over "clocks" property. > So, it is valid to probe the driver with a NULL pointer for info->clk. > > > if (of_property_read_u32(np, "clock-frequency", &clk)) { > > /* Get clk rate through clk driver if present */ > info->clk = devm_clk_get(&ofdev->dev, NULL); > if (IS_ERR(info->clk)) { > dev_warn(&ofdev->dev, > "clk or clock-frequency not defined\n"); > return PTR_ERR(info->clk); > } > > ret = clk_prepare_enable(info->clk); > if (ret < 0) > return ret; > > clk = clk_get_rate(info->clk); > } > > > As a result, we need to make sure the clk pointer is valid > before calling clk_disable_unprepare(). > > > If we could support pointer checking in callees, we would be able to > clean-up lots of clock consumers. > > I'm not sure if you meant to use that example for the error pointer case? It bails out if clk_get() returns an error pointer. I'm all for a no-op in clk_disable()/unprepare() when the pointer is NULL. But when it's an error pointer the driver should be handling it and bail out before it would ever call enable/prepare on it or disable/unprepare. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project