Re: [PATCH 5/5] arm64: dts: allwinner: a64-amarula-relic: Add OV5640 camera node

On Mon, Dec 3, 2018 at 3:55 PM Chen-Yu Tsai [off-list ref] wrote:

On Mon, Dec 3, 2018 at 6:08 PM Jagan Teki [off-list ref] wrote:

quoted

Amarula A64-Relic board by default bound with OV5640 camera,
so add support for it with below pin information.

- PE13, PE12 via i2c-gpio bitbanging
- CLK_CSI_MCLK as external clock
- PE1 as external clock pin muxing
- DLDO3 as vcc-csi supply
- DLDO3 as AVDD supply
- ALDO1 as DOVDD supply
- ELDO3 as DVDD supply
- PE14 gpio for reset pin
- PE15 gpio for powerdown pin

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 .../allwinner/sun50i-a64-amarula-relic.dts    | 54 +++++++++++++++++++
 arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi |  5 ++
 2 files changed, 59 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-amarula-relic.dts b/arch/arm64/boot/dts/allwinner/sun50i-a64-amarula-relic.dts
index 6cb2b7f0c817..9ac6d773188b 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-amarula-relic.dts
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-amarula-relic.dts

@@ -22,6 +22,41 @@
                stdout-path = "serial0:115200n8";
        };

+       i2c-csi {
+               compatible = "i2c-gpio";
+               sda-gpios = <&pio 4 13 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+               scl-gpios = <&pio 4 12 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

FYI our hardware doesn't do open drain.

True, but the kernel is enforcing it seems, from the change from [1].
does that mean Linux use open drain even though hardware doens't have?
or did I miss anything?

[    3.659235] gpio-141 (sda): enforced open drain please flag it
properly in DT/ACPI DSDT/board file
[    3.679954] gpio-140 (scl): enforced open drain please flag it
properly in DT/ACPI DSDT/board file
[    3.814878] i2c-gpio i2c-csi: using lines 141 (SDA) and 140 (SCL)

quoted

+               i2c-gpio,delay-us = <5>;
+               #address-cells = <1>;
+               #size-cells = <0>;
+
+               ov5640: camera@3c {
+                       compatible = "ovti,ov5640";
+                       reg = <0x3c>;
+                       pinctrl-names = "default";
+                       pinctrl-0 = <&csi_mclk_pin>;
+                       clocks = <&ccu CLK_CSI_MCLK>;
+                       clock-names = "xclk";
+
+                       AVDD-supply = <&reg_dldo3>;
+                       DOVDD-supply = <&reg_aldo1>;

DOVDD is the supply for I/O. You say it is ALDO1 here.

quoted

+                       DVDD-supply = <&reg_eldo3>;
+                       reset-gpios = <&pio 4 14 GPIO_ACTIVE_LOW>; /* CSI-RST-R: PE14 */
+                       powerdown-gpios = <&pio 4 15 GPIO_ACTIVE_HIGH>; /* CSI-STBY-R: PE15 */
+
+                       port {
+                               ov5640_ep: endpoint {
+                                       remote-endpoint = <&csi_ep>;
+                                       bus-width = <8>;
+                                       hsync-active = <1>; /* Active high */
+                                       vsync-active = <0>; /* Active low */
+                                       data-active = <1>;  /* Active high */
+                                       pclk-sample = <1>;  /* Rising */
+                               };
+                       };
+               };
+       };
+
        wifi_pwrseq: wifi-pwrseq {
                compatible = "mmc-pwrseq-simple";
                clocks = <&rtc 1>;

@@ -30,6 +65,25 @@
        };
 };

+&csi {
+       vcc-csi-supply = <&reg_dldo3>;

But here you say the SoC-side pins are driven from DLDO3.

This is a somewhat odd mismatch.

Regardless, the ov5640 driver enables all three regulators at probe time.
Shouldn't that be enough to get the I2C bus working? The pin voltage
supply does not belong here.

It is working w/o supplying PE group, but I think that may be reason
of supplying similar regulator via DOVDD on sensor side. But we need
to make sure the pin-group must be powered right like DSI, HDMI? if
yes may be we do something via power-domain driver like other SoC's
does or do we have any other option.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/gpio/gpiolib.c?id=f926dfc112bc6cf41d7068ee5e3f261e13a5bec8

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