From mboxrd@z Thu Jan  1 00:00:00 1970
From: marex@denx.de (Marek Vasut)
Date: Mon, 21 Jan 2013 22:00:36 +0100
Subject: [PATCH 1/2] iio: mxs: Add MX23 support into the IIO driver
In-Reply-To: <CAHXqBFLQUY6g6p988MVkk=sRu44B5tEzDMH2UbU2n2UDda0Q-A@mail.gmail.com>
References: <1358798722-25102-1-git-send-email-marex@denx.de>
 <CAHXqBFLQUY6g6p988MVkk=sRu44B5tEzDMH2UbU2n2UDda0Q-A@mail.gmail.com>
Message-ID: <201301212200.36917.marex@denx.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Dear Micha? Miros?aw,

> 2013/1/21 Marek Vasut <marex@denx.de>:
> > This patch adds support for i.MX23 into the LRADC driver. The LRADC
> > block on MX23 is not much different from the one on MX28, thus this
> > is only a few changes fixing the parts that are specific to MX23.
> 
> [...]
> 
> > +struct mxs_lradc_of_config {
> > +       const int               irq_count;
> > +       const char * const      *irq_name;
> > +};
> > +
> > +static const struct mxs_lradc_of_config const mxs_lradc_of_config[] = {
> > +       [IMX23_LRADC] = {
> > +               .irq_count      = ARRAY_SIZE(mx23_lradc_irq_names),
> > +               .irq_name       = mx23_lradc_irq_names,
> > +       },
> > +       [IMX28_LRADC] = {
> > +               .irq_count      = ARRAY_SIZE(mx28_lradc_irq_names),
> > +               .irq_name       = mx28_lradc_irq_names,
> > +       },
> > +};
> > +
> > 
> >  enum mxs_lradc_ts {
> >  
> >         MXS_LRADC_TOUCHSCREEN_NONE = 0,
> >         MXS_LRADC_TOUCHSCREEN_4WIRE,
> > 
> > @@ -857,8 +890,19 @@ static void mxs_lradc_hw_stop(struct mxs_lradc
> > *lradc)
> > 
> >                 writel(0, lradc->base + LRADC_DELAY(i));
> >  
> >  }
> > 
> > +static const struct of_device_id mxs_lradc_dt_ids[] = {
> > +       { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC,
> > }, +       { .compatible = "fsl,imx28-lradc", .data = (void
> > *)IMX28_LRADC, }, +       { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
> > +
> 
> Why not s/(void \*)\(IMX.._LRADC\)/\&mxs_lradc_of_config[\1]/ ?

Check the register layout, it differs between MX23 and MX28, that's one reason, 
since were we to access differently placed registers, we can do it easily as in 
the SSP/I2C drivers.

Moreover, there are some features on the MX28 that are not on the MX23 (like 
voltage treshold triggers and touchbuttons), with this setup, we can easily 
check what we're running at at runtime and determine to disallow these.

>>From my point of view, using the number (IMX23_LRADC / IMX28_LRADC) is much more 
convenient in the long run.

Best regards,
Marek Vasut