RE: [PATCH 1/2] pinctrl: pinctrl-imx: add IBE and OBE SoC property

["A.S. Dong" <aisheng.dong@xxxxxxx>]

> -----Original Message-----
> From: Stefan Agner [mailto:stefan@xxxxxxxx]
> Sent: Tuesday, May 16, 2017 1:11 AM
> To: A.S. Dong
> Cc: linux-gpio@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linus.walleij@xxxxxxxxxx; shawnguo@xxxxxxxxxx; Jacky Bai; Andy Duan;
> kernel@xxxxxxxxxxxxxx; Alexandre Courbot
> Subject: Re: [PATCH 1/2] pinctrl: pinctrl-imx: add IBE and OBE SoC
> property
> 
> On 2017-05-14 23:48, Dong Aisheng wrote:
> > iMX ULP has different IOB/OBE shift from Vibrid, so let's make
> 
> s/Vibrid/Vybrid
> 
> > it a SoC property.
> >
> > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Cc: Alexandre Courbot <gnurou@xxxxxxxxx>
> > Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
> > Cc: Stefan Agner <stefan@xxxxxxxx>
> > Cc: Fugang Duan <fugang.duan@xxxxxxx>
> > Cc: Bai Ping <ping.bai@xxxxxxx>
> > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> > ---
> >  drivers/pinctrl/freescale/pinctrl-imx.c     | 8 ++++----
> >  drivers/pinctrl/freescale/pinctrl-imx.h     | 2 ++
> >  drivers/pinctrl/freescale/pinctrl-imx7ulp.c | 2 ++
> >  drivers/pinctrl/freescale/pinctrl-vf610.c   | 2 ++
> >  4 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pinctrl/freescale/pinctrl-imx.c
> > b/drivers/pinctrl/freescale/pinctrl-imx.c
> > index 57e1f7a..0d6aaca 100644
> > --- a/drivers/pinctrl/freescale/pinctrl-imx.c
> > +++ b/drivers/pinctrl/freescale/pinctrl-imx.c
> > @@ -331,8 +331,8 @@ static int imx_pmx_gpio_set_direction(struct
> > pinctrl_dev *pctldev,
> >  	u32 reg;
> >
> >  	/*
> > -	 * Only Vybrid has the input/output buffer enable flags (IBE/OBE)
> > -	 * They are part of the shared mux/conf register.
> > +	 * Only Vybrid and iMX ULP has the input/output buffer enable flags
> > +	 * (IBE/OBE) They are part of the shared mux/conf register.
> >  	 */
> >  	if (!(info->flags & SHARE_MUX_CONF_REG))
> >  		return 0;
> > @@ -344,9 +344,9 @@ static int imx_pmx_gpio_set_direction(struct
> > pinctrl_dev *pctldev,
> >  	/* IBE always enabled allows us to read the value "on the wire" */
> >  	reg = readl(ipctl->base + pin_reg->mux_reg);
> >  	if (input)
> > -		reg &= ~0x2;
> > +		reg = (reg & ~info->obe_bit) | info->ibe_bit;
> >  	else
> > -		reg |= 0x2;
> > +		reg = (reg & ~info->ibe_bit) | info->obe_bit;
> 
> Why disabling IBE bit now? As the comment above states, it is really handy
> to leave the input buffer enabled so we can read back the true value on
> the wire...
> 

Does Vybrid reply on this bit to read the status of output from
Port Data Input Register (GPIOx_PDIR)?

Then, it is a bit strange that read status from input register when the GPIO is
Actually configured as output.

Probably it works on Vybrid, but I don't know if it's valid for MX7ULP.

For MX7ULP, we will read input or output register accordingly by checking
GPIO direction register (PDDR) and we will not enable Input buffer if the GPIO
is configured as output, this also save a bit power.

I know Vybrid has no PDDR, probably that's why you enable IBE by default
always.

Regards
Dong Aisheng

> --
> Stefan
> 
> >  	writel(reg, ipctl->base + pin_reg->mux_reg);
> >
> >  	return 0;
> > diff --git a/drivers/pinctrl/freescale/pinctrl-imx.h
> > b/drivers/pinctrl/freescale/pinctrl-imx.h
> > index eb0ce95..9ded65d 100644
> > --- a/drivers/pinctrl/freescale/pinctrl-imx.h
> > +++ b/drivers/pinctrl/freescale/pinctrl-imx.h
> > @@ -67,6 +67,8 @@ struct imx_pinctrl_soc_info {
> >  	/* MUX_MODE shift and mask in case SHARE_MUX_CONF_REG */
> >  	unsigned int mux_mask;
> >  	u8 mux_shift;
> > +	u32 ibe_bit;
> > +	u32 obe_bit;
> >
> >  	/* generic pinconf */
> >  	bool generic_pinconf;
> > diff --git a/drivers/pinctrl/freescale/pinctrl-imx7ulp.c
> > b/drivers/pinctrl/freescale/pinctrl-imx7ulp.c
> > index dead416..f724a01 100644
> > --- a/drivers/pinctrl/freescale/pinctrl-imx7ulp.c
> > +++ b/drivers/pinctrl/freescale/pinctrl-imx7ulp.c
> > @@ -324,6 +324,8 @@ static struct imx_pinctrl_soc_info
> imx7ulp_pinctrl_info = {
> >  	.flags = ZERO_OFFSET_VALID | SHARE_MUX_CONF_REG,
> >  	.mux_mask = 0xf00,
> >  	.mux_shift = 8,
> > +	.ibe_bit = BIT(16),
> > +	.obe_bit = BIT(17),
> >  	.generic_pinconf = true,
> >  	.custom_params = imx7ulp_cfg_params,
> >  	.num_custom_params = ARRAY_SIZE(imx7ulp_cfg_params), diff --git
> > a/drivers/pinctrl/freescale/pinctrl-vf610.c
> > b/drivers/pinctrl/freescale/pinctrl-vf610.c
> > index 3bd8556..c0823f9 100644
> > --- a/drivers/pinctrl/freescale/pinctrl-vf610.c
> > +++ b/drivers/pinctrl/freescale/pinctrl-vf610.c
> > @@ -301,6 +301,8 @@ static struct imx_pinctrl_soc_info
> vf610_pinctrl_info = {
> >  	.flags = SHARE_MUX_CONF_REG | ZERO_OFFSET_VALID,
> >  	.mux_mask = 0x700000,
> >  	.mux_shift = 20,
> > +	.ibe_bit = BIT(0),
> > +	.obe_bit = BIT(1),
> >  };
> >
> >  static const struct of_device_id vf610_pinctrl_of_match[] = {
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html