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SubjectRE: [PATCH v4 5/8] MFD: ti_am335x_tscadc: Add DT support
Date
On Wed, Jan 30, 2013 at 16:10:09, Koen Kooi wrote:
>
> Op 24 jan. 2013, om 04:45 heeft "Patil, Rachna" <rachna@ti.com> het volgende geschreven:
>
> > From: "Patil, Rachna" <rachna@ti.com>
> >
> > Make changes to add DT support in the MFD core driver.
> >
> > Signed-off-by: Patil, Rachna <rachna@ti.com>
> > ---
> > Changes in v4:
> > Non-standard properties prefixed with vendor name.
> >
> > drivers/mfd/ti_am335x_tscadc.c | 28 +++++++++++++++++++++++-----
> > 1 file changed, 23 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/mfd/ti_am335x_tscadc.c
> > b/drivers/mfd/ti_am335x_tscadc.c index e9f3fb5..87b446b 100644
> > --- a/drivers/mfd/ti_am335x_tscadc.c
> > +++ b/drivers/mfd/ti_am335x_tscadc.c
> > @@ -22,6 +22,8 @@
> > #include <linux/regmap.h>
> > #include <linux/mfd/core.h>
> > #include <linux/pm_runtime.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> >
> > #include <linux/mfd/ti_am335x_tscadc.h> #include
> > <linux/input/ti_am335x_tsc.h>
> > @@ -64,20 +66,31 @@ static int ti_tscadc_probe(struct platform_device *pdev)
> > struct resource *res;
> > struct clk *clk;
> > struct mfd_tscadc_board *pdata = pdev->dev.platform_data;
> > + struct device_node *node = pdev->dev.of_node;
> > struct mfd_cell *cell;
> > int err, ctrl;
> > int clk_value, clock_rate;
> > - int tsc_wires, adc_channels = 0, total_channels;
> > + int tsc_wires = 0, adc_channels = 0, total_channels;
> >
> > - if (!pdata) {
> > + if (!pdata && !pdev->dev.of_node) {
> > dev_err(&pdev->dev, "Could not find platform data\n");
> > return -EINVAL;
> > }
> >
> > - if (pdata->adc_init)
> > - adc_channels = pdata->adc_init->adc_channels;
> > + if (pdev->dev.platform_data) {
> > + if (pdata->tsc_init)
> > + tsc_wires = pdata->tsc_init->wires;
> > +
> > + if (pdata->adc_init)
> > + adc_channels = pdata->adc_init->adc_channels;
> > + } else {
> > + node = of_find_node_by_name(pdev->dev.of_node, "tsc");
> > + of_property_read_u32(node, "ti,wires", &tsc_wires);
> > +
> > + node = of_find_node_by_name(pdev->dev.of_node, "adc");
> > + of_property_read_u32(node, "ti,adc-channels", &adc_channels);
> > + }
>
> Since AM335x is DT only, why is there a platform data codepath and why is it the first branch it tries? And I guess the next question is related to the first: why doesn't it work when used with DT? When I copy over the nodes from the evm.dts to my board I get "tsc tsc: Missing platform data" in dmesg.

This IP came up 1st on AM335x, but it is not platform dependent. The driver can be used on other platforms where-in DT is not supported.
According to the maintainers platform data takes precedence over DT. Hence the order.

I do not see "Missing platform data" error msg in the latest driver. I am not able to trace from where this got populated.

>
> What are the chances this driver will work when applied on top of 3.8-rcX? Has it even been tested with that? Has it been tested at all?

This driver has been tested on top of v3.8-rc3 on a AM335x EVM.

Regards,
Rachna



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