Hi Mark,
Date: Tue, 28 Apr 2020 06:24:10 +0200 From: Lukasz Majewski lukma@denx.de
Hi Lukasz,
Hi Mark,
The fix in commit b7adcdd073c0 has the side-effect that the regulator will be disabled when requesting the relevant gpio in regulator_common_ofdata_to_platdata() and enabled in regulator_pre_probe() when the regulator was already enabled. This leads to a short interruption in the 3.3V power to the PCIe slot on the firefly-rk3399 which makes an ADATA SX8000NP NVMe SSD unhappy.
Fix this by setting the GPIOD_IS_OUT_ACTIVE flag again when the 'regulator-boot-on' property is set, but check for this property explicitly instead of relying on the "boot_on" member of the uclass platdata.
Signed-off-by: Mark Kettenis kettenis@openbsd.org
drivers/power/regulator/regulator-uclass.c | 3 --- drivers/power/regulator/regulator_common.c | 2 ++ 2 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/power/regulator/regulator-uclass.c b/drivers/power/regulator/regulator-uclass.c index c9d26344d7..90961de95c 100644 --- a/drivers/power/regulator/regulator-uclass.c +++ b/drivers/power/regulator/regulator-uclass.c @@ -464,9 +464,6 @@ static int regulator_pre_probe(struct udevice *dev) (uc_pdata->min_uA == uc_pdata->max_uA)) uc_pdata->flags |= REGULATOR_FLAG_AUTOSET_UA;
- if (uc_pdata->boot_on)
regulator_set_enable(dev, uc_pdata->boot_on);- return 0;
}
diff --git a/drivers/power/regulator/regulator_common.c b/drivers/power/regulator/regulator_common.c index 33b73b7c2f..bc13b88476 100644 --- a/drivers/power/regulator/regulator_common.c +++ b/drivers/power/regulator/regulator_common.c @@ -17,6 +17,8 @@ int regulator_common_ofdata_to_platdata(struct udevice *dev, if (!dev_read_bool(dev, "enable-active-high")) flags |= GPIOD_ACTIVE_LOW;
if (dev_read_bool(dev, "regulator-boot-on"))
flags |= GPIOD_IS_OUT_ACTIVE;/* Get optional enable GPIO desc */ gpio = &dev_pdata->gpio;
Sorry, but this is a simple revert of my commit and breaks use cases described in the commit message of this fix.
No, it isn't a simple revert, and I don't think it will break the i.MX ethernet driver.
I need to check this - as this issue was critical for i.MX53 (it caused the board not being able to update U-Boot after this change).
I think the analysis in the commit message is a bit flawed. I don't think there was something actually wrong with commit e8e9715df2d4 because at the time regulator_pre_probe() was called before regulator_common_ofdata_to_platdata().
This was changed in 29f7d05a347ab ("dm: core: Move ofdata_to_platdata() call earlier"), which was the commit git bisect led me to. After that commit the boot_on member no longer being set.
My diff is indeed mostly a revert of yours, but it replaces the boot_on member check with an explicit check of the "boot-on" property. As a result the GPIOD_IS_OUT_ACTIVE flag is set correctly and the regulator should be turned on (or stay on in my case).
I must have overlooked the difference. In my case the regulator had to be powered up early (in the preprobe) so ETH initialization would be performed with enabled power.
Do you see some kind of "glitch" on the gpio in regulator_common_of_platdata?
I don't have the tools to actually measure the pin but yes all the evidence points to a glitch. I also instrumented the actual gpio driver and it defenitely is setting the pin low (0) and setting it high (1) again later. So I think it is essential that GPIOD_IS_OUT_ACTIVE is set when the gpio is set in the gpio_request_by_name() call. Enabling it later later isn't good enough.
What I'm seeing on my hardware is that the NVMe device is still present on the PCIe bus, but reports a bogus size and a different firmware version string. I'm fairly certain that a glitch on the 3.3V pin is interrupting the load of the firmware that is stored on the card itself. When this happens, the only thing that fixes it is a complete power cycle of the board.
The regulator-boot-on property [1] shall prevent from the issue you described in the commit message of this revert.
Links: [1] - https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bind...
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de