On Fri, Jul 13, 2012 at 12:09:01PM +0530, Jayachandran C wrote: > From: Ganesan Ramalingam <[email protected]> > > 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. > > Signed-off-by: Ganesan Ramalingam <[email protected]> > Signed-off-by: Jayachandran C <[email protected]> > --- > .../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(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt > b/Documentation/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> > > +Optional properties: > +- reg-shift : device register offsets are shifted by this value > +- regstep : deprecated, use reg-shift above > + > Example: > > i2c0: ocores@a0000000 { > @@ -17,9 +20,10 @@ Example: > compatible = "opencores,i2c-ocores"; > reg = <0xa0000000 0x8>; > interrupts = <10>; > - regstep = <1>; > clock-frequency = <20000000>; > > + reg-shift = <0>; /* 8 bit registers */ > + > dummy@60 { > compatible = "dummy"; > reg = <0x60>; > diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c > index e8159db..fb8db30 100644 > --- a/drivers/i2c/busses/i2c-ocores.c > +++ b/drivers/i2c/busses/i2c-ocores.c > @@ -25,10 +25,11 @@ > #include <linux/slab.h> > #include <linux/io.h> > #include <linux/of_i2c.h> > +#include <linux/log2.h> > > 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 { > > 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)); > } > > 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)); > } > > static void ocores_process(struct ocores_i2c *i2c) > @@ -219,22 +220,30 @@ static struct i2c_adapter ocores_adapter = { > static int ocores_i2c_of_probe(struct platform_device *pdev, > struct ocores_i2c *i2c) > { > - const __be32* val; > - > - val = of_get_property(pdev->dev.of_node, "regstep", NULL); > - if (!val) { > - dev_err(&pdev->dev, "Missing required parameter 'regstep'\n"); > - return -ENODEV; > - } > - i2c->regstep = be32_to_cpup(val); > + struct device_node *np = 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 = ilog2(val); > + dev_warn(&pdev->dev, > + "regstep property deprecated, use reg-shift\n"); > + } > + } else > + i2c->reg_shift = 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.
>
> - val = 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 = be32_to_cpup(val) / 1000;
> + i2c->clock_khz = 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
--
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