Re: [PATCH] ti_tscadc: Match mfd sub devices to regmap interface

On 10/31/2012 05:41 AM, Russ Dill wrote:

On Wed, Oct 31, 2012 at 8:55 AM, Pantelis Antoniou
[off-list ref] wrote:

quoted

The MFD parent device now uses a regmap, instead of direct
memory access. Use the same method in the sub devices to avoid
nasty surprises.

Also rework the channel initialization of tiadc a bit.

Signed-off-by: Pantelis Antoniou <redacted>
---
 drivers/iio/adc/ti_am335x_adc.c           | 27 +++++++++++++++++++--------
 drivers/input/touchscreen/ti_am335x_tsc.c | 16 +++++++++++++---
 drivers/mfd/ti_am335x_tscadc.c            |  7 +++++--
 3 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index d48fd79..5f325c1 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c

@@ -23,7 +23,9 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/machine.h>
 #include <linux/iio/driver.h>
+#include <linux/regmap.h>

+#include <linux/io.h>
 #include <linux/mfd/ti_am335x_tscadc.h>
 #include <linux/platform_data/ti_am335x_adc.h>

@@ -36,13 +38,17 @@ struct tiadc_device {

 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
 {
-       return readl(adc->mfd_tscadc->tscadc_base + reg);
+       unsigned int val;
+
+       val = (unsigned int)-1;
+       regmap_read(adc->mfd_tscadc->regmap_tscadc, reg, &val);
+       return val;
 }

Would it be cleaner to instead do:

static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
{
       unsigned int val;

       return regmap_read(adc->mfd_tscadc->regmap_tscadc, reg, &val) ? : val;
}

In my opinion the best would be to just mimic the regmap interface here. Return
an error code or 0 and pass the value back through a pointer parameter.