[PATCH v2] bus: imx-weim: support CS GPR config for imx6q-weim

[Shawn Guo]

On Thu, Feb 13, 2014 at 11:38:25PM +0100, Philippe De Muyter wrote:
> Hi Shawn,
> 
> On Thu, Feb 13, 2014 at 08:59:02PM +0800, Shawn Guo wrote:
> > For imx6q-weim type of device, there might a WEIM CS space configuration
> > register in General Purpose Register controller, e.g. IOMUXC_GPR1 on
> > i.MX6Q.
> > 
> > Depending on which configuration of the following 4 is chosen for given
> > system, IOMUXC_GPR1[11:0] should be set up as 05, 033, 0113 or 01111
> > correspondingly.
> > 
> > 	CS0(128M) CS1(0M)  CS2(0M)  CS3(0M)
> > 	CS0(64M)  CS1(64M) CS2(0M)  CS3(0M)
> > 	CS0(64M)  CS1(32M) CS2(32M) CS3(0M)
> > 	CS0(32M)  CS1(32M) CS2(32M) CS3(32M)
> > 
> > The patch creates a function for imx6q-weim type of device, which scans
> > 'ranges' property of WEIM node and build the GPR value incrementally.
> > Thus the WEIM CS GPR can be set up automatically at boot time.
> 
> Please add that text to Documentation/devicetree/bindings/bus/imx-weim.txt.

Since the patch does not add any new device tree properties, I do not
think we need to necessarily update bindings doc in this patch.  I
prefer to improve the doc with another separate patch.

> 
> > 
> > Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
> > ---
> > Changes since v1:
> >  - Drop device tree property fsl,weim-cs-gpr
> >  - Use octal value for IOMUXC_GPR1[11:0] bit field
> >  - Use of_property_for_each_u32() to build gprval incrementally
> > 
> >  drivers/bus/imx-weim.c |   59 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 59 insertions(+)
> > 
> > diff --git a/drivers/bus/imx-weim.c b/drivers/bus/imx-weim.c
> > index 3ef58c8..a120c93 100644
> > --- a/drivers/bus/imx-weim.c
> > +++ b/drivers/bus/imx-weim.c
> > @@ -11,6 +11,9 @@
> >  #include <linux/clk.h>
> >  #include <linux/io.h>
> >  #include <linux/of_device.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
> > +#include <linux/regmap.h>
> >  
> >  struct imx_weim_devtype {
> >  	unsigned int	cs_count;
> > @@ -56,6 +59,59 @@ static const struct of_device_id weim_id_table[] = {
> >  };
> >  MODULE_DEVICE_TABLE(of, weim_id_table);
> >  
> > +static int __init imx6q_weim_gpr_setup(struct platform_device *pdev)
> > +{
> > +	struct device_node *np = pdev->dev.of_node;
> > +	struct property *prop;
> > +	const __be32 *p;
> > +	struct regmap *gpr;
> > +	u32 gprvals[4] = {
> > +		05,	/* CS0(128M) CS1(0M)  CS2(0M)  CS3(0M) */
> > +		033,	/* CS0(64M)  CS1(64M) CS2(0M)  CS3(0M) */
> > +		0113,	/* CS0(64M)  CS1(32M) CS2(32M) CS3(0M) */
> > +		0111,	/* CS0(64M)  CS1(32M) CS2(32M) CS3(0M) */
> 
> 		01111,	/* CS0(32M)  CS1(32M) CS2(32M) CS3(32M) */

Oops, thanks.

> 
> > +	};
> > +	u32 gprval = 0;
> > +	u32 val;
> > +	int len;
> > +	int cs = 0;
> > +	int i = 0;
> > +
> > +	gpr = syscon_regmap_lookup_by_compatible("fsl,imx6q-iomuxc-gpr");
> > +	if (IS_ERR(gpr)) {
> > +		dev_err(&pdev->dev, "failed to find fsl,imx6q-iomuxc-gpr\n");
> > +		return -ENOENT;
> > +	}
> > +
> > +	prop = of_find_property(np, "ranges", &len);
> > +	if (prop == NULL)
> > +		return -ENOENT;
> > +	if (len % (sizeof(u32) * 4))
> > +		return -EINVAL;
> > +
> > +	of_property_for_each_u32(np, "ranges", prop, p, val) {
> > +		if (i % 4 == 0) {
> > +			cs = val;
> > +		} else if (i % 4 == 3 && val) {
> > +			val /= SZ_64M;
> > +			val = (val << 1) | 1;
> 
> or
> 			val = (val / SZ_32M) | 1;

Okay.

> 
> > +			gprval |= val << cs * 3;
> > +		}
> > +		i++;
> > +	}
> 
> You may replace the tests above (from "prop = of_find_property" to "EINVAL;")
> by :
> 	if (i == 0 || (i % 4))
> 		goto err;

Yeah, it's better.

I will roll these changes into v3.

> > +
> > +	for (i = 0; i < ARRAY_SIZE(gprvals); i++) {
> > +		if (gprval == gprvals[i]) {
> > +			/* Found it. Set up IOMUXC_GPR1[11:0] with it. */
> > +			regmap_update_bits(gpr, IOMUXC_GPR1, 0xfff, gprval);
> > +			return 0;
> > +		}
> > +	}
> > +
> 
>    err:
> 
> > +	dev_err(&pdev->dev, "Invalid 'ranges' configuration\n");
> > +	return -EINVAL;
> > +}
> > +
> >  /* Parse and set the timing for this device. */
> >  static int __init weim_timing_setup(struct device_node *np, void __iomem *base,
> >  				    const struct imx_weim_devtype *devtype)
> > @@ -92,6 +148,9 @@ static int __init weim_parse_dt(struct platform_device *pdev,
> >  	struct device_node *child;
> >  	int ret;
> >  
> > +	if (of_device_is_compatible(pdev->dev.of_node, "fsl,imx6q-weim"))
> > +		imx6q_weim_gpr_setup(pdev);
> > +
> >  	for_each_child_of_node(pdev->dev.of_node, child) {
> >  		if (!child->name)
> >  			continue;
> > -- 
> > 1.7.9.5
> > 
> 
> I have tested this v2 patch, and, except for the typo (0111 instead of 01111),
> it works perfectly.

Thanks for testing.

Shawn