RE: [PATCH V2 4/8] gpio: vf610: add optional clock support

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

> -----Original Message-----
> From: Stefan Agner [mailto:stefan@xxxxxxxx]
> Sent: Friday, October 26, 2018 1:59 AM
[...]
> 
> On 23.10.2018 13:49, A.s. Dong wrote:
> > Some SoCs need the gpio clock to be enabled before accessing HW
> > registers. This patch add the optional clock handling.
> >
> > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Cc: Stefan Agner <stefan@xxxxxxxx>
> > Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
> > Cc: linux-gpio@xxxxxxxxxxxxxxx
> > Signed-off-by: Dong Aisheng <aisheng.dong@xxxxxxx>
> > ---
> > v1->v2:
> >  * new patch
> > ---
> >  drivers/gpio/gpio-vf610.c | 20 ++++++++++++++++++++
> >  1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/gpio/gpio-vf610.c b/drivers/gpio/gpio-vf610.c
> > index d4ad6d0..cbc4f44 100644
> > --- a/drivers/gpio/gpio-vf610.c
> > +++ b/drivers/gpio/gpio-vf610.c
> > @@ -16,6 +16,7 @@
> >   */
> >
> >  #include <linux/bitops.h>
> > +#include <linux/clk.h>
> >  #include <linux/err.h>
> >  #include <linux/gpio.h>
> >  #include <linux/init.h>
> > @@ -256,6 +257,7 @@ static int vf610_gpio_probe(struct platform_device
> > *pdev)  {
> >  	struct device *dev = &pdev->dev;
> >  	struct device_node *np = dev->of_node;
> > +	struct clk *clk_gpio, *clk_port;
> >  	struct vf610_gpio_port *port;
> >  	struct resource *iores;
> >  	struct gpio_chip *gc;
> > @@ -280,6 +282,24 @@ static int vf610_gpio_probe(struct platform_device
> *pdev)
> >  	if (port->irq < 0)
> >  		return port->irq;
> >
> > +	clk_gpio = devm_clk_get(&pdev->dev, "gpio");
> > +	clk_port = devm_clk_get(&pdev->dev, "port");
> 
> Are you sure that those are two independent clocks? On i.MX 7 usually there
> was a single clock gate controlling multiple clocks at once (which should be
> modeled as a single clock gate in the clock tree).
> 

Yes, they're two separate clocks in HW for gpio and port controller respectively.
One is for GPIO general purpose input/output function which another for port Interrupt.
Just like we have separate register ranges for gpio and port.

Regards
Dong Aisheng

> --
> Stefan
> 
> > +	if ((PTR_ERR(clk_gpio) == -EPROBE_DEFER) ||
> > +	    (PTR_ERR(clk_port) == -EPROBE_DEFER)) {
> > +		return -EPROBE_DEFER;
> > +	} else if (!IS_ERR_OR_NULL(clk_gpio) &&
> > +		   !IS_ERR_OR_NULL(clk_port)) {
> > +		ret = clk_prepare_enable(clk_gpio);
> > +		if (ret)
> > +			return ret;
> > +
> > +		ret = clk_prepare_enable(clk_port);
> > +		if (ret) {
> > +			clk_disable_unprepare(clk_gpio);
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	gc = &port->gc;
> >  	gc->of_node = np;
> >  	gc->parent = dev;