[RFC] serial: ns16550: Set read/write functions depending on reg-io-width

[Sascha Hauer]

On Mon, Feb 20, 2017 at 02:12:21PM +0100, Wadim Egorov wrote:
> Is this patch okay?

I hope so, it's already applied ;)

Sascha

> 
> 
> Am 09.02.2017 um 10:36 schrieb Wadim Egorov:
> > Set proper register read/write functions depending on reg-io-width
> > device tree property.
> >
> > Signed-off-by: Wadim Egorov <w.egorov at phytec.de>
> > ---
> >
> > of_platform_device_create() creates resources in the device_d struct.
> > ns16550_init_iomem() and ns16550_init_ioport() are reading the resources
> > and it's flags (register width).
> > So both functions are not failing, because there is a valid resource.
> > The res->flags might be not set at all. And if it is not set, the driver
> > will use always IORESOURCE_MEM_8BIT.
> >
> > With this patch the probe_dt() func will override the read/write funcs,
> > if there is a valid reg-io-width property.
> > ---
> >  drivers/serial/serial_ns16550.c | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> >
> > diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
> > index c6548e3..752e77b 100644
> > --- a/drivers/serial/serial_ns16550.c
> > +++ b/drivers/serial/serial_ns16550.c
> > @@ -287,12 +287,31 @@ static int ns16550_tstc(struct console_device *cdev)
> >  static void ns16550_probe_dt(struct device_d *dev, struct ns16550_priv *priv)
> >  {
> >  	struct device_node *np = dev->device_node;
> > +	u32 width;
> >  
> >  	if (!IS_ENABLED(CONFIG_OFDEVICE))
> >  		return;
> >  
> >  	of_property_read_u32(np, "clock-frequency", &priv->plat.clock);
> >  	of_property_read_u32(np, "reg-shift", &priv->plat.shift);
> > +	if (!of_property_read_u32(np, "reg-io-width", &width))
> > +		switch (width) {
> > +		case 1:
> > +			priv->read_reg = ns16550_read_reg_mmio_8;
> > +			priv->write_reg = ns16550_write_reg_mmio_8;
> > +			break;
> > +		case 2:
> > +			priv->read_reg = ns16550_read_reg_mmio_16;
> > +			priv->write_reg = ns16550_write_reg_mmio_16;
> > +			break;
> > +		case 4:
> > +			priv->read_reg = ns16550_read_reg_mmio_32;
> > +			priv->write_reg = ns16550_write_reg_mmio_32;
> > +			break;
> > +		default:
> > +			dev_err(dev, "unsupported reg-io-width (%d)\n",
> > +				width);
> > +		}
> >  }
> >  
> >  static struct ns16550_drvdata ns16450_drvdata = {
> 
> 
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