Hi Simon,
On 28/12/18 3:57 AM, Simon Glass wrote:
Hi Lokesh,
On Mon, 24 Dec 2018 at 04:08, Lokesh Vutla <lokeshvu...@ti.com> wrote:
commit 4f86a724e82c0 ("power: regulator: denied disable on always-on
regulator") throws an error when requested to disable an always-on
regulator. It is right that an always-on regulator should not be
attempted to be disabled. But at the same time regulator framework
should not return an error when such request is received. Instead
it should just return success without attempting to disable the
specified regulator. This is because the requesting driver will
not have the idea if the regulator is always-on or not. The
requesting driver will always try to enable/disable regulator as
per the required flow. So it is upto regulator framework to not
break such scenarios.
Can the caller not check the error code? It is -EACCES in this case.
We considered this an one of the option but I ended up fixing regulator
framework due to the following reasons:
- If regulator framework returns -EACCES on this scenario then:
- -EACCES should be checked in all the existing usage of the api[1] or else
someone else might encounter the same problem.
- Any future usage of the api should take of handling this error.
- From a client driver perspective it is not really an error. It is doing the
right thing and receiving an error might be confusing.
Hope this is clear. Also just to add one more point, I adapted this error
handling from Linux kernel[2].
[1] ➜ u-boot git:(master) git grep -in "regulator_set_enable(.*, false)"
cmd/regulator.c:410: ret = regulator_set_enable(dev, false);
drivers/mmc/mmc.c:2552: int ret = regulator_set_enable(mmc->vmmc_supply,
false);
drivers/mmc/omap_hsmmc.c:473: ret = regulator_set_enable(priv->pbias_supply,
false);
drivers/mmc/omap_hsmmc.c:478: ret = regulator_set_enable(mmc->vqmmc_supply,
false);
drivers/net/fec_mxc.c:1414: regulator_set_enable(priv->phy_supply, false);
drivers/phy/meson-gxl-usb2.c:174: int ret =
regulator_set_enable(priv->phy_supply, false);
drivers/phy/phy-rcar-gen3.c:101: return
regulator_set_enable(priv->vbus_supply, false);
drivers/phy/phy-stm32-usbphyc.c:251: ret =
regulator_set_enable(usbphyc_phy->vdda1v1, false);
drivers/phy/phy-stm32-usbphyc.c:257: ret =
regulator_set_enable(usbphyc_phy->vdda1v8, false);
drivers/phy/phy-stm32-usbphyc.c:263: ret =
regulator_set_enable(usbphyc_phy->vdd, false);
drivers/usb/host/dwc2.c:199: ret =
regulator_set_enable(priv->vbus_supply, false);
drivers/usb/host/ehci-generic.c:60: return
regulator_set_enable(priv->vbus_supply, false);
drivers/usb/host/xhci-rockchip.c:161: ret =
regulator_set_enable(plat->vbus_supply, false);
drivers/video/pwm_backlight.c:160: ret =
regulator_set_enable(priv->reg, false);
test/dm/adc.c:74: ut_assertok(regulator_set_enable(supply, false));
[2] [1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/regulator/core.c#n2333
Thanks and regards,
Lokesh
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