RE: [RFC PATCH v2 2/4] pinctrl: imx: add pinmux imx driver

[Dong Aisheng-B29396]

> -----Original Message-----
> From: Guo Shawn-R65073
> Sent: Thursday, December 15, 2011 4:18 PM
> To: Dong Aisheng-B29396
> Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linus.walleij@xxxxxxxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
> kernel@xxxxxxxxxxxxxx; grant.likely@xxxxxxxxxxxx; rob.herring@xxxxxxxxxxx
> Subject: Re: [RFC PATCH v2 2/4] pinctrl: imx: add pinmux imx driver
> Importance: High
> 
> On Thu, Dec 15, 2011 at 12:03:40AM +0800, Dong Aisheng wrote:
> > The driver contains the initial support for imx53 and imx6q.
> >
> > Signed-off-by: Dong Aisheng <dong.aisheng@xxxxxxxxxx>
> > Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> > Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > Cc: Shawn Guo <shanw.guo@xxxxxxxxxxxxx>
> > ---
> >  drivers/pinctrl/Kconfig           |   20 ++
> >  drivers/pinctrl/Makefile          |    3 +
> >  drivers/pinctrl/pinmux-imx-core.c |  435
> ++++++++++++++++++++++++++++++++++++
> >  drivers/pinctrl/pinmux-imx-core.h |   86 +++++++
> >  drivers/pinctrl/pinmux-imx53.c    |  443
> +++++++++++++++++++++++++++++++++++++
> >  drivers/pinctrl/pinmux-imx6q.c    |  433
> ++++++++++++++++++++++++++++++++++++
> >  6 files changed, 1420 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig index
> > e17e2f8..268c212 100644
> > --- a/drivers/pinctrl/Kconfig
> > +++ b/drivers/pinctrl/Kconfig
> > @@ -20,6 +20,26 @@ config DEBUG_PINCTRL
> >  	help
> >  	  Say Y here to add some extra checks and diagnostics to PINCTRL
> calls.
> >
> > +config PINMUX_IMX
> > +	bool "Freescale IMX core pinmux driver"
> > +	depends on ARCH_MXC
> > +
> > +config PINMUX_IMX53
> > +	bool "IMX53 pinmux driver"
> > +	depends on ARCH_MX5
> > +	select PINMUX
> > +	select PINMUX_IMX
> > +	help
> > +	  Say Y here to enable the imx6q pinmux driver
> 
> s/imx6q/imx53
> 
Acked.

> > +
> > +config PINMUX_IMX6Q
> > +	bool "IMX6Q pinmux driver"
> > +	depends on SOC_IMX6Q
> > +	select PINMUX
> > +	select PINMUX_IMX
> > +	help
> > +	  Say Y here to enable the imx6q pinmux driver
> > +
> 
> [...]
> 
> > +#ifdef CONFIG_OF
> > +static int __devinit imx_pmx_parse_functions(struct device_node *np,
> > +			struct imx_pinctrl_info *info, u32 num) {
> > +	struct imx_pmx_func *function;
> > +	struct imx_pin_group *group;
> > +	int ret, len;
> > +
> > +	dev_dbg(info->dev, "parse function %d\n", num);
> > +
> > +	group = &info->groups[num];
> > +	function = &info->functions[num];
> > +
> > +	/* Initialise group */
> > +	ret = of_property_read_string(np, "grp_name", &group->name);
> > +	if (ret) {
> > +		dev_err(info->dev, "failed to get grp_name\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = of_property_read_u32(np, "num_pins", &group->num_pins);
> > +	if (ret) {
> > +		dev_err(info->dev, "failed to get num_pins\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = of_property_read_u32(np, "num_mux", &group->num_mux);
> > +	if (ret) {
> > +		dev_err(info->dev, "failed to get num_mux\n");
> > +		return ret;
> > +	}
> > +
> > +	if (group->num_pins != group->num_mux)
> > +		return -EINVAL;
> > +
> > +	group->pins = devm_kzalloc(info->dev, group->num_pins *
> sizeof(unsigned int),
> > +				GFP_KERNEL);
> > +	group->mux_mode = devm_kzalloc(info->dev, group->num_mux *
> sizeof(unsigned int),
> > +				GFP_KERNEL);
> > +	if (!group->pins || !group->mux_mode)
> > +		return -ENOMEM;
> > +
> > +	/* sanity check */
> > +	if (of_get_property(np, "grp_pins", &len) &&
> > +		len != group->num_pins * sizeof(unsigned int)) {
> 
> Since we can figure out the 'num_pins' here, why do we bother to encode
> it in dts?
> 
Since the pin group is easily to define wrongly by mistake when pins are many,
I would add num_pins in dts to double check in driver to improve the code
Stability.

> > +		dev_err(info->dev, "wrong pins number?\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (of_get_property(np, "grp_mux", &len) &&
> > +		len != group->num_mux * sizeof(unsigned int)) {
> 
> ditto
> 
> > +		dev_err(info->dev, "wrong pin mux number?\n");
> > +		return -EINVAL;
> > +	}
> 
> --
> Regards,
> Shawn

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