From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH 2/4] i2c: i2c-ocores: Use reg-shift property Date: Fri, 13 Jul 2012 11:17:31 +0200 Message-ID: <20120713091731.GI32184@pengutronix.de> References: <1342161543-5838-1-git-send-email-jayachandranc@netlogicmicro.com> <1342161543-5838-3-git-send-email-jayachandranc@netlogicmicro.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="BghK6+krpKHjj+jk" Return-path: Content-Disposition: inline In-Reply-To: <1342161543-5838-3-git-send-email-jayachandranc-oSioyQM9ZPnuBjGU1YDckgC/G2K4zDHf@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jayachandran C Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jacmet-OfajU3CKLf1/SzgSGea1oA@public.gmane.org, richard.rojfors-gfIc91nka+FZroRs9YW3xA@public.gmane.org, devicetree-discuss-mnsaURCQ41sdnm+yROfE0A@public.gmane.org, Ganesan Ramalingam List-Id: linux-i2c@vger.kernel.org --BghK6+krpKHjj+jk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jul 13, 2012 at 12:09:01PM +0530, Jayachandran C wrote: > From: Ganesan Ramalingam >=20 > Deprecate 'regstep' property and use the standard 'reg-shift' property > for register offset shifts. 'regstep' will still be supported as an > optional property, but will give a warning when used. >=20 > Signed-off-by: Ganesan Ramalingam > Signed-off-by: Jayachandran C > --- > .../devicetree/bindings/i2c/i2c-ocores.txt | 8 +++- > drivers/i2c/busses/i2c-ocores.c | 39 ++++++++++++--= ------ > include/linux/i2c-ocores.h | 2 +- > 3 files changed, 31 insertions(+), 18 deletions(-) >=20 > diff --git a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt b/Docum= entation/devicetree/bindings/i2c/i2c-ocores.txt > index bfec894..1c9334b 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt > @@ -4,11 +4,14 @@ Required properties: > - compatible : "opencores,i2c-ocores" > - reg : bus address start and address range size of device > - interrupts : interrupt number > -- regstep : size of device registers in bytes > - clock-frequency : frequency of bus clock in Hz > - #address-cells : should be <1> > - #size-cells : should be <0> > =20 > +Optional properties: > +- reg-shift : device register offsets are shifted by this value > +- regstep : deprecated, use reg-shift above > + > Example: > =20 > i2c0: ocores@a0000000 { > @@ -17,9 +20,10 @@ Example: > compatible =3D "opencores,i2c-ocores"; > reg =3D <0xa0000000 0x8>; > interrupts =3D <10>; > - regstep =3D <1>; > clock-frequency =3D <20000000>; > =20 > + reg-shift =3D <0>; /* 8 bit registers */ > + > dummy@60 { > compatible =3D "dummy"; > reg =3D <0x60>; > diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-oco= res.c > index e8159db..fb8db30 100644 > --- a/drivers/i2c/busses/i2c-ocores.c > +++ b/drivers/i2c/busses/i2c-ocores.c > @@ -25,10 +25,11 @@ > #include > #include > #include > +#include > =20 > struct ocores_i2c { > void __iomem *base; > - int regstep; > + int reg_shift; > wait_queue_head_t wait; > struct i2c_adapter adap; > struct i2c_msg *msg; > @@ -71,12 +72,12 @@ struct ocores_i2c { > =20 > static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value) > { > - iowrite8(value, i2c->base + reg * i2c->regstep); > + iowrite8(value, i2c->base + (reg << i2c->reg_shift)); > } > =20 > static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg) > { > - return ioread8(i2c->base + reg * i2c->regstep); > + return ioread8(i2c->base + (reg << i2c->reg_shift)); > } > =20 > static void ocores_process(struct ocores_i2c *i2c) > @@ -219,22 +220,30 @@ static struct i2c_adapter ocores_adapter =3D { > static int ocores_i2c_of_probe(struct platform_device *pdev, > struct ocores_i2c *i2c) > { > - const __be32* val; > - > - val =3D of_get_property(pdev->dev.of_node, "regstep", NULL); > - if (!val) { > - dev_err(&pdev->dev, "Missing required parameter 'regstep'\n"); > - return -ENODEV; > - } > - i2c->regstep =3D be32_to_cpup(val); > + struct device_node *np =3D pdev->dev.of_node; > + u32 val; > + > + if (of_property_read_u32(np, "reg-shift", &val)) { > + /* no 'reg-shift', check for deprecated 'regstep' */ > + if (!of_property_read_u32(np, "regstep", &val)) { > + if (!is_power_of_2(val)) { > + dev_err(&pdev->dev, "invalid regstep %d\n", > + val); > + return -EINVAL; > + } > + i2c->reg_shift =3D ilog2(val); > + dev_warn(&pdev->dev, > + "regstep property deprecated, use reg-shift\n"); > + } > + } else > + i2c->reg_shift =3D val; Now you are assigning an u32 to an int. Regstep will never be really a huge number, but still... Also, braces around else-block according to coding style. > =20 > - val =3D of_get_property(pdev->dev.of_node, "clock-frequency", NULL); > - if (!val) { > + if (of_property_read_u32(np, "clock-frequency", &val)) { > dev_err(&pdev->dev, > "Missing required parameter 'clock-frequency'\n"); > return -ENODEV; > } > - i2c->clock_khz =3D be32_to_cpup(val) / 1000; > + i2c->clock_khz =3D val / 1000; Okay, "/ 1000" will guarantee that the divided value will fit into an int. Yet, what do we gain by not using u32? Regards, Wolfram --=20 Pengutronix e.K. | Wolfram Sang | Industrial Linux Solutions | http://www.pengutronix.de/ | --BghK6+krpKHjj+jk Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAk//56sACgkQD27XaX1/VRtpvgCfef5rj2c9Vzx5y7fqaN7Wxv/2 zv8An3SukdTT7tIId9SxcvGK4hp07bbk =is4g -----END PGP SIGNATURE----- --BghK6+krpKHjj+jk--