Re: [PATCH RESEND v2 1/2] Input: touchscreen: ads7846: keep copy of pdata in private struct

[Dmitry Torokhov]

Hi Daniel,

On Sun, Jun 30, 2013 at 11:09:14PM +0200, Daniel Mack wrote:
> +
> +     if (!pdata->model)
> +             pdata->model = 7846;
> +
> +     if (!pdata->vref_delay_usecs)
> +             pdata->vref_delay_usecs = 100;
> +
> +     if (!pdata->x_plate_ohms)
> +             pdata->x_plate_ohms = 400;
> +
> +     if (!pdata->pressure_max)
> +             pdata->pressure_max = ~0;

We should not be changing the platform data as the device does not own
it and it may well be declared as a constant structure.

In fact, I have a patch that declares pdata pointer as const.

-- 
Dmitry


Input: ads7846 - make sure we do not change platform data

From: Dmitry Torokhov <dmitry.torok...@gmail.com>

Let's declare platform data a const pointer so that we don't accitentally
change it. Also fetch it with dev_get_platdata().

Signed-off-by: Dmitry Torokhov <dmitry.torok...@gmail.com>
---
 drivers/input/touchscreen/ads7846.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/ads7846.c 
b/drivers/input/touchscreen/ads7846.c
index 84ccf14..5ff0419 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -961,9 +961,9 @@ static int ads7846_resume(struct device *dev)
 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 
 static int ads7846_setup_pendown(struct spi_device *spi,
-                                          struct ads7846 *ts)
+                                struct ads7846 *ts,
+                                const struct ads7846_platform_data *pdata)
 {
-       struct ads7846_platform_data *pdata = spi->dev.platform_data;
        int err;
 
        /*
@@ -1003,7 +1003,7 @@ static int ads7846_setup_pendown(struct spi_device *spi,
  * use formula #2 for pressure, not #3.
  */
 static void ads7846_setup_spi_msg(struct ads7846 *ts,
-                               const struct ads7846_platform_data *pdata)
+                                 const struct ads7846_platform_data *pdata)
 {
        struct spi_message *m = &ts->msg[0];
        struct spi_transfer *x = ts->xfer;
@@ -1203,10 +1203,10 @@ static void ads7846_setup_spi_msg(struct ads7846 *ts,
 
 static int ads7846_probe(struct spi_device *spi)
 {
+       const struct ads7846_platform_data *pdata = dev_get_platdata(&spi->dev);
        struct ads7846 *ts;
        struct ads7846_packet *packet;
        struct input_dev *input_dev;
-       struct ads7846_platform_data *pdata = spi->dev.platform_data;
        unsigned long irq_flags;
        int err;
 
@@ -1281,7 +1281,7 @@ static int ads7846_probe(struct spi_device *spi)
                ts->filter = ads7846_no_filter;
        }
 
-       err = ads7846_setup_pendown(spi, ts);
+       err = ads7846_setup_pendown(spi, ts, pdata);
        if (err)
                goto err_cleanup_filter;
 
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