Lee, Arnd, I had to make changes in this patch to address Rob's comments. reg-io-width is now in bytes while bus-width was a value in bits. Could you please review this patch ? Thanks, Damien On Mon, Nov 30, 2015 at 01:00:15PM -0600, Rob Herring wrote: > On Mon, Nov 30, 2015 at 10:59:47AM -0500, Damien Riegel wrote: > > Currently syscon has a fixed configuration of 32 bits for register and > > values widths. In some cases, it would be desirable to be able to > > customize the value width. > > > > For example, certain boards (like the ones manufactured by Technologic > > Systems) have a FPGA that is memory-mapped, but its registers are only > > 16-bit wide. > > > > This patch adds an optional "reg-io-width" DT binding for syscon that > > allows to change the width for the data bus (i.e. val_bits). If this > > property is provided, it will also set the register stride to > > reg-io-width's value. If not provided, the default configuration is > > used. > > > > Signed-off-by: Damien Riegel <damien.riegel@xxxxxxxxxxxxxxxxxxxx> > > Acked-by: Rob Herring <robh@xxxxxxxxxx> > > > --- > > Documentation/devicetree/bindings/mfd/syscon.txt | 4 ++++ > > drivers/mfd/syscon.c | 13 +++++++++++++ > > 2 files changed, 17 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Documentation/devicetree/bindings/mfd/syscon.txt > > index fe8150b..408f768 100644 > > --- a/Documentation/devicetree/bindings/mfd/syscon.txt > > +++ b/Documentation/devicetree/bindings/mfd/syscon.txt > > @@ -13,6 +13,10 @@ Required properties: > > - compatible: Should contain "syscon". > > - reg: the register region can be accessed from syscon > > > > +Optional property: > > +- reg-io-width: the size (in bytes) of the IO accesses that should be > > + performed on the device. > > + > > Examples: > > gpr: iomuxc-gpr@020e0000 { > > compatible = "fsl,imx6q-iomuxc-gpr", "syscon"; > > diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c > > index 176bf0f..b7aabee 100644 > > --- a/drivers/mfd/syscon.c > > +++ b/drivers/mfd/syscon.c > > @@ -47,6 +47,7 @@ static struct syscon *of_syscon_register(struct device_node *np) > > struct syscon *syscon; > > struct regmap *regmap; > > void __iomem *base; > > + u32 reg_io_width; > > int ret; > > struct regmap_config syscon_config = syscon_regmap_config; > > > > @@ -69,6 +70,18 @@ static struct syscon *of_syscon_register(struct device_node *np) > > else if (of_property_read_bool(np, "little-endian")) > > syscon_config.val_format_endian = REGMAP_ENDIAN_LITTLE; > > > > + /* > > + * search for reg-io-width property in DT. If it is not provided, > > + * default to 4 bytes. regmap_init_mmio will return an error if values > > + * are invalid so there is no need to check them here. > > + */ > > + ret = of_property_read_u32(np, "reg-io-width", ®_io_width); > > + if (ret) > > + reg_io_width = 4; > > + > > + syscon_config.reg_stride = reg_io_width; > > + syscon_config.val_bits = reg_io_width * 8; > > + > > regmap = regmap_init_mmio(NULL, base, &syscon_config); > > if (IS_ERR(regmap)) { > > pr_err("regmap init failed\n"); > > -- > > 2.5.0 > > -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html