From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lee Jones Subject: Re: [PATCH v7 2/6] mfd: syscon: add a DT property to set value width Date: Mon, 7 Dec 2015 09:40:20 +0000 Message-ID: <20151207094020.GF3384@x1> References: <1448899191-13891-1-git-send-email-damien.riegel@savoirfairelinux.com> <1448899191-13891-3-git-send-email-damien.riegel@savoirfairelinux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1448899191-13891-3-git-send-email-damien.riegel@savoirfairelinux.com> Sender: linux-kernel-owner@vger.kernel.org To: Damien Riegel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Russell King , Shawn Guo , Sascha Hauer , Arnd Bergmann , Samuel Ortiz , Wim Van Sebroeck , Guenter Roeck , kernel@savoirfairelinux.com List-Id: devicetree@vger.kernel.org On Mon, 30 Nov 2015, Damien Riegel wrote: > Currently syscon has a fixed configuration of 32 bits for register an= d > values widths. In some cases, it would be desirable to be able to > customize the value width. >=20 > For example, certain boards (like the ones manufactured by Technologi= c > Systems) have a FPGA that is memory-mapped, but its registers are onl= y > 16-bit wide. >=20 > 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. >=20 > Signed-off-by: Damien Riegel > --- > Documentation/devicetree/bindings/mfd/syscon.txt | 4 ++++ > drivers/mfd/syscon.c | 13 +++++++++++++ > 2 files changed, 17 insertions(+) Applied, thanks. > diff --git a/Documentation/devicetree/bindings/mfd/syscon.txt b/Docum= entation/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 > =20 > +Optional property: > +- reg-io-width: the size (in bytes) of the IO accesses that should b= e > + performed on the device. > + > Examples: > gpr: iomuxc-gpr@020e0000 { > compatible =3D "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 dev= ice_node *np) > struct syscon *syscon; > struct regmap *regmap; > void __iomem *base; > + u32 reg_io_width; > int ret; > struct regmap_config syscon_config =3D syscon_regmap_config; > =20 > @@ -69,6 +70,18 @@ static struct syscon *of_syscon_register(struct de= vice_node *np) > else if (of_property_read_bool(np, "little-endian")) > syscon_config.val_format_endian =3D REGMAP_ENDIAN_LITTLE; > =20 > + /* > + * 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 val= ues > + * are invalid so there is no need to check them here. > + */ > + ret =3D of_property_read_u32(np, "reg-io-width", ®_io_width); > + if (ret) > + reg_io_width =3D 4; > + > + syscon_config.reg_stride =3D reg_io_width; > + syscon_config.val_bits =3D reg_io_width * 8; > + > regmap =3D regmap_init_mmio(NULL, base, &syscon_config); > if (IS_ERR(regmap)) { > pr_err("regmap init failed\n"); --=20 Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org =E2=94=82 Open source software for ARM SoCs =46ollow Linaro: Facebook | Twitter | Blog