[RFC PATCH] mxs: Don't enable 4P2 reg if mx28 is powered only from DCDC_BATT without 5V

mxs_power_enable_4p2() was added to mxs_batt_boot() in 'commit a0f97610757d ("ARM: mxs: Enable DCDC converter for battery boot")' to enable DCDC converter when board is powered from 5V and has detected sufficient battery voltage. This involves enabling 4P2 regulator and there is a code in mxs_power_enable_4p2() that disables VDDIO, VDDA, VDDD outputs of the DCDC converter and enables BO for each power rail e.g.
setbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_DISABLE_FET | POWER_VDDIOCTRL_PWDN_BRNOUT);
In case the mx28 is powered by the 5V source and linear regulators are supplying power to the VDDIO, VDDA, VDDD rails there is no issue.
However if the mx28 is powered by the DCDC_BATT source only without 5V, disabling the DCDC converter outputs causes brownout power down.
The proposed solution is not to call mxs_power_enable_4p2() at all if the mx28 is powered by the DCDC_BATT source only. There is no reason to enable 4P2 regulator in this case and setup of all registers is done in mxs_batt_boot().
Also there is no need to enable 5V brownout in mxs_power_init() in this case.
Please consider if this is acceptable and I will submit a proper patch.
Signed-off-by: Alan Kay alan@londelec.com ---
arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index c33170f06d..c8feadce54 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -752,7 +752,9 @@ static void mxs_batt_boot(void) POWER_5VCTRL_CHARGE_4P2_ILIMIT_MASK, 0x8 << POWER_5VCTRL_CHARGE_4P2_ILIMIT_OFFSET);
+#ifndef CONFIG_SPL_MXS_NO_VDD5V_SOURCE mxs_power_enable_4p2(); +#endif }
/** @@ -1267,7 +1269,9 @@ void mxs_power_init(void) POWER_CTRL_VBUS_VALID_IRQ | POWER_CTRL_BATT_BO_IRQ | POWER_CTRL_DCDC4P2_BO_IRQ, &power_regs->hw_power_ctrl_clr);
+#ifndef CONFIG_SPL_MXS_NO_VDD5V_SOURCE writel(POWER_5VCTRL_PWDN_5VBRNOUT, &power_regs->hw_power_5vctrl_set); +#endif
early_delay(1000); }

Hi Alan,
[Adding Lukasz and Cody]
On Tue, Aug 30, 2022 at 2:49 PM Alan Kay alan@londelec.com wrote:
mxs_power_enable_4p2() was added to mxs_batt_boot() in 'commit a0f97610757d ("ARM: mxs: Enable DCDC converter for battery boot")' to enable DCDC converter when board is powered from 5V and has detected sufficient battery voltage. This involves enabling 4P2 regulator and there is a code in mxs_power_enable_4p2() that disables VDDIO, VDDA, VDDD outputs of the DCDC converter and enables BO for each power rail e.g.
setbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_DISABLE_FET | POWER_VDDIOCTRL_PWDN_BRNOUT);
In case the mx28 is powered by the 5V source and linear regulators are supplying power to the VDDIO, VDDA, VDDD rails there is no issue.
However if the mx28 is powered by the DCDC_BATT source only without 5V, disabling the DCDC converter outputs causes brownout power down.
The proposed solution is not to call mxs_power_enable_4p2() at all if the mx28 is powered by the DCDC_BATT source only. There is no reason to enable 4P2 regulator in this case and setup of all registers is done in mxs_batt_boot().
Also there is no need to enable 5V brownout in mxs_power_init() in this case.
Please consider if this is acceptable and I will submit a proper patch.
Signed-off-by: Alan Kay alan@londelec.com
Cody also sent a fix for this issue:
https://patchwork.ozlabs.org/project/uboot/patch/20230703163340.101490-2-cod...

Hi Fabio, Alan,
Hi Alan,
[Adding Lukasz and Cody]
On Tue, Aug 30, 2022 at 2:49 PM Alan Kay alan@londelec.com wrote:
mxs_power_enable_4p2() was added to mxs_batt_boot() in 'commit a0f97610757d ("ARM: mxs: Enable DCDC converter for battery boot")' to enable DCDC converter when board is powered from 5V and has detected sufficient battery voltage. This involves enabling 4P2 regulator and there is a code in mxs_power_enable_4p2() that disables VDDIO, VDDA, VDDD outputs of the DCDC converter and enables BO for each power rail e.g.
setbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_DISABLE_FET |
POWER_VDDIOCTRL_PWDN_BRNOUT);
In case the mx28 is powered by the 5V source and linear regulators are supplying power to the VDDIO, VDDA, VDDD rails there is no issue.
However if the mx28 is powered by the DCDC_BATT source only without 5V, disabling the DCDC converter outputs causes brownout power down.
The proposed solution is not to call mxs_power_enable_4p2() at all if the mx28 is powered by the DCDC_BATT source only. There is no reason to enable 4P2 regulator in this case and setup of all registers is done in mxs_batt_boot().
Also there is no need to enable 5V brownout in mxs_power_init() in this case.
Please consider if this is acceptable and I will submit a proper patch.
Signed-off-by: Alan Kay alan@londelec.com
Cody also sent a fix for this issue:
https://patchwork.ozlabs.org/project/uboot/patch/20230703163340.101490-2-cod...
Isn't this already addressed with: https://source.denx.de/u-boot/u-boot/-/commit/79230640cb4fb780e2be9bb9a47b31...
Please also look into the recent patches for imx287 (xea board for reference):
tig -- arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
At least SHA1: 65b9b3462bec2966911658836983819ab4e4823e
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Hi Lukasz,
On Mon, Oct 9, 2023 at 8:49 AM Lukasz Majewski lukma@denx.de wrote:
Hi Fabio, Alan,
Hi Alan,
[Adding Lukasz and Cody]
On Tue, Aug 30, 2022 at 2:49 PM Alan Kay alan@londelec.com wrote:
mxs_power_enable_4p2() was added to mxs_batt_boot() in 'commit a0f97610757d ("ARM: mxs: Enable DCDC converter for battery boot")' to enable DCDC converter when board is powered from 5V and has detected sufficient battery voltage. This involves enabling 4P2 regulator and there is a code in mxs_power_enable_4p2() that disables VDDIO, VDDA, VDDD outputs of the DCDC converter and enables BO for each power rail e.g.
setbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_DISABLE_FET |
POWER_VDDIOCTRL_PWDN_BRNOUT);
In case the mx28 is powered by the 5V source and linear regulators are supplying power to the VDDIO, VDDA, VDDD rails there is no issue.
However if the mx28 is powered by the DCDC_BATT source only without 5V, disabling the DCDC converter outputs causes brownout power down.
The proposed solution is not to call mxs_power_enable_4p2() at all if the mx28 is powered by the DCDC_BATT source only. There is no reason to enable 4P2 regulator in this case and setup of all registers is done in mxs_batt_boot().
Also there is no need to enable 5V brownout in mxs_power_init() in this case.
Please consider if this is acceptable and I will submit a proper patch.
Signed-off-by: Alan Kay alan@londelec.com
Cody also sent a fix for this issue:
https://patchwork.ozlabs.org/project/uboot/patch/20230703163340.101490-2-cod...
Isn't this already addressed with: https://source.denx.de/u-boot/u-boot/-/commit/79230640cb4fb780e2be9bb9a47b31...
Please also look into the recent patches for imx287 (xea board for reference):
tig -- arch/arm/cpu/arm926ejs/mxs/spl_power_init.c
At least SHA1: 65b9b3462bec2966911658836983819ab4e4823e
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Erika Unter HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
The patch: https://source.denx.de/u-boot/u-boot/-/commit/79230640cb4fb780e2be9bb9a47b31... does fix the issue, please feel free to discard my patch, thank you.
Best regards, Alan Kay

Hi Alan and Cody,
On Mon, Oct 9, 2023 at 9:45 AM Alan Kay alan@londelec.com wrote:
The patch: https://source.denx.de/u-boot/u-boot/-/commit/79230640cb4fb780e2be9bb9a47b31... does fix the issue, please feel free to discard my patch, thank you.
Ok, what about the patch below?
https://patchwork.ozlabs.org/project/uboot/patch/20230703205700.9120-1-cody@...
Is this still needed?

On Fri, Dec 15, 2023 at 1:20 PM Fabio Estevam festevam@gmail.com wrote:
Ok, what about the patch below?
https://patchwork.ozlabs.org/project/uboot/patch/20230703205700.9120-1-cody@...
Is this still needed?
I looked in the i.MX28 Reference Manual, and the one above looks a correct fix. I will queue it.

On Fri, Dec 15, 2023 at 7:23 PM Fabio Estevam festevam@gmail.com wrote:
On Fri, Dec 15, 2023 at 1:20 PM Fabio Estevam festevam@gmail.com wrote:
Ok, what about the patch below?
https://patchwork.ozlabs.org/project/uboot/patch/20230703205700.9120-1-cody@...
Is this still needed?
I looked in the i.MX28 Reference Manual, and the one above looks a correct fix. I will queue it.
Yes, this patch is needed, thank you for queuing it.
participants (4)
-
Alan Kay
-
Cody Green
-
Fabio Estevam
-
Lukasz Majewski