AXP808 vs. AXP806 debugged, no difference? (Was: [PATCH v6 5/5] ARM: dts: sun9i: Initial support for the Sunchip CX-A99 board)

[Chen-Yu Tsai]

On Fri, Feb 17, 2017 at 5:16 AM, Rask Ingemann Lambertsen
<rask at formelder.dk> wrote:
> In summary: I'll propose a new property "extended-address" or so to the
> existing "x-powers,axp806" compatible, because the axp808 does seem to have
> the register at 0xff after all, it just needs a value of 0 instead of the 16
> which drivers/mfd/axp20x.c as of recently is now writing unconditionally
> to 0xff. A new "x-powers,axp808" compatible and new AXP808_ID is therefore
> not needed. This should make for a simpler and smaller patch.

It might be the same core as the AXP806, though without a datasheet to actually
confirm it, it might be best to stick to a new compatible.

However, we could add a new property "x-powers,master-mode". If the driver
sees it, it would clear bit 4, instead of setting it. The hardware bit is
latched from the external pin, so this would be per board.

Regards
ChenYu

> On Wed, Feb 15, 2017 at 12:35:39AM +0100, Rask Ingemann Lambertsen wrote:
>> As to touching the register at 0xff, it would be interesting to know more
>> precisely what goes wrong. The symptom is these messages in the log:
>>
>> [    3.209573] axp20x-rsb sunxi-rsb-745: AXP20x variant AXP806 found
>> [    3.210153] axp20x-rsb sunxi-rsb-745: Failed to set masks in 0x40: -5
>> [    3.210178] axp20x-rsb sunxi-rsb-745: failed to add irq chip: -5
>> [    3.210306] axp20x-rsb: probe of sunxi-rsb-745 failed with error -5
>>
>> I haven't yet looked further into what happens at the RSB bus level.
>
> With the patch below applied for debugging purposes and using the
> "xpowers,axp806" compatible, I get:
>
> [    3.209955] axp20x-rsb sunxi-rsb-745: AXP20x variant AXP806 found
> [    3.210065] axp20x-rsb sunxi-rsb-745: Chip ID read 1 = 0x60
> [    3.210119] axp20x-rsb sunxi-rsb-745: Reg addr ext = 0x0
> [    3.210171] axp20x-rsb sunxi-rsb-745: Bus addr ext = 0x0
> [    3.210381] axp20x-rsb sunxi-rsb-745: Chip ID read 2 = 0x60
> (16 written to register 0xff here)
> [    3.210570] sunxi-rsb 8003400.i2c: RSB transfer data error
> [    3.210596] sunxi-rsb 8003400.i2c: RSB error reading dev 58 register 3 length 1.
> [    3.210625] axp20x-rsb sunxi-rsb-745: Chip ID read 3 = 0xffffffff
> (0 written to register 0xff here)
> [    3.210828] axp20x-rsb sunxi-rsb-745: Chip ID read 4 = 0x60
>
> I.e. register 0xff (Reg addr ext) and 0xfe (Bus addr ext) exist with a
> default of 0. After writing 16 to register 0xff, the chip ID (register 3)
> can not be read, but writing 0 to register 0xff makes the AXP808 respond
> again and the board boots up as normal.
>
> Also, can someone with an AXP806 confirm that it does use the same chip ID
> of 0x60 as the AXP808?
>
> diff --git a/drivers/mfd/axp20x.c b/drivers/mfd/axp20x.c
> index 125b470..db557f3 100644
> --- a/drivers/mfd/axp20x.c
> +++ b/drivers/mfd/axp20x.c
> @@ -910,9 +910,40 @@ int axp20x_device_probe(struct axp20x_dev *axp20x)
>          * address.
>          */
>         if (axp20x->variant == AXP806_ID)
> +       {
> +               int dummy;
> +
> +               dummy = -1;
> +               regmap_read(axp20x->regmap, AXP806_CHIP_ID, &dummy);
> +               dev_info(axp20x->dev, "Chip ID read 1 = 0x%x\n", dummy);
> +
> +               regmap_read(axp20x->regmap, AXP806_REG_ADDR_EXT, &dummy);
> +               dev_info(axp20x->dev, "Reg addr ext = 0x%x\n", dummy);
> +               regmap_read(axp20x->regmap, AXP806_BUS_ADDR_EXT, &dummy);
> +               dev_info(axp20x->dev, "Bus addr ext = 0x%x\n", dummy);
> +
> +               regmap_reinit_cache(axp20x->regmap, axp20x->regmap_cfg);
> +               dummy = -1;
> +               regmap_read(axp20x->regmap, AXP806_CHIP_ID, &dummy);
> +               dev_info(axp20x->dev, "Chip ID read 2 = 0x%x\n", dummy);
> +
>                 regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
>                              AXP806_REG_ADDR_EXT_ADDR_SLAVE_MODE);
>
> +               regmap_reinit_cache(axp20x->regmap, axp20x->regmap_cfg);
> +               dummy = -1;
> +               regmap_read(axp20x->regmap, AXP806_CHIP_ID, &dummy);
> +               dev_info(axp20x->dev, "Chip ID read 3 = 0x%x\n", dummy);
> +
> +               regmap_write(axp20x->regmap, AXP806_REG_ADDR_EXT,
> +                            0);
> +
> +               regmap_reinit_cache(axp20x->regmap, axp20x->regmap_cfg);
> +               dummy = -1;
> +               regmap_read(axp20x->regmap, AXP806_CHIP_ID, &dummy);
> +               dev_info(axp20x->dev, "Chip ID read 4 = 0x%x\n", dummy);
> +       }
> +
>         ret = regmap_add_irq_chip(axp20x->regmap, axp20x->irq,
>                           IRQF_ONESHOT | IRQF_SHARED | axp20x->irq_flags,
>                            -1, axp20x->regmap_irq_chip, &axp20x->regmap_irqc);
> diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c
> index 795c9d9..85e4926 100644
> --- a/drivers/bus/sunxi-rsb.c
> +++ b/drivers/bus/sunxi-rsb.c
> @@ -349,6 +349,10 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
>  unlock:
>         mutex_unlock(&rsb->lock);
>
> +       if (ret)
> +               dev_dbg(rsb->dev, "RSB error reading dev %u register %u length %u.\n",
> +                       rtaddr, addr, (unsigned int) len);
> +
>         return ret;
>  }
>
> @@ -386,6 +390,10 @@ static int sunxi_rsb_write(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr,
>
>         mutex_unlock(&rsb->lock);
>
> +       if (ret)
> +               dev_dbg(rsb->dev, "RSB error writing dev %u register %u length %u.\n",
> +                       rtaddr, addr, (unsigned int) len);
> +
>         return ret;
>  }
>
> diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
> index cc6364b..4b81226 100644
> --- a/drivers/bus/Makefile
> +++ b/drivers/bus/Makefile
> @@ -24,3 +24,4 @@ obj-$(CONFIG_UNIPHIER_SYSTEM_BUS)     += uniphier-system-bus.o
>  obj-$(CONFIG_VEXPRESS_CONFIG)  += vexpress-config.o
>
>  obj-$(CONFIG_DA8XX_MSTPRI)     += da8xx-mstpri.o
> +CFLAGS_sunxi-rsb.o             += -DDEBUG -DEBUG
>
> --
> Rask Ingemann Lambertsen