From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Kettenis Date: Tue, 28 Apr 2020 11:23:31 +0200 (CEST) Subject: [PATCH] regulator: fix: enable gpio when requested In-Reply-To: <20200428062410.73ef4efe@jawa> (message from Lukasz Majewski on Tue, 28 Apr 2020 06:24:10 +0200) References: <20200427090947.75951-1-kettenis@openbsd.org> <20200428062410.73ef4efe@jawa> Message-ID: <01619e6f9447d890@bloch.sibelius.xs4all.nl> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de > Date: Tue, 28 Apr 2020 06:24:10 +0200 > From: Lukasz Majewski 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 > > --- > > 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 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). > 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/bindings/regulator/regulator.yaml#L40 > > 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 at denx.de