Hi Laurent,
> [snip]
>
> > > +static inline void xlnx_dsi_writel(void __iomem *base, int offset, u32 val)
> > > +{
> > > + writel(val, base + offset);
> > > +}
> > > +
> > > +static inline u32 xlnx_dsi_readl(void __iomem *base, int offset)
> > > +{
> > > + return readl(base + offset);
> > > +}
> >
> > When I see implementations like this I wonder if a regmap would be
> > beneficial?
>
> regmap often seems overkill to me when the driver only needs plain
> 32-bit mmio read/write, given the overhead it adds at runtime. Is it
> just me ?
There are several points that speaks for using regmap:
- The interface is well known
- It has nice helpers - like update_bits
- No need for own wrappers, that sometimes are made in creative ways
(not the case here)
- There is a possibility to add some run-time checks so one can catch
attempt to write outside the register window, write to read-only
registers etc.
On top of this - it is simple to configure:
static const struct regmap_config regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
};
>From the probe function:
priv->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(priv->regs))
return dev_err_probe(dev, PTR_ERR(priv->regs), "Failed to get memory resource\n");
regmap_cfg = regmap_config;
regmap_cfg.max_register = res->end - res->start;
priv->regmap = devm_regmap_init_mmio(dev, priv->regs, ®map_cfg);
if (IS_ERR(priv->regmap))
return dev_err_probe(dev, PTR_ERR(priv->regmap), "Failed to init regmap\n");
The one point that brought me over was the well known interface.
But using wrappers works too.
Sam
