Sourav,
On Wed, Feb 2, 2011 at 21:00, Sourav Poddar <sourav.poddar@xxxxxx> wrote:
> gpio_pendown in ads7846_probe is not getting initalized (defaulted to 0)
> resulting in gpio_free being called without a gpio_request. This
> results in the following backtrace in bootup (at least on an OMAP3430 SDP).
NACK to this patch. see my comments below.
>
> ------------[ cut here ]------------
> WARNING: at drivers/gpio/gpiolib.c:1258 gpio_free+0x100/0x12c()
> Modules linked in:
> [<c0061208>] (unwind_backtrace+0x0/0xe4) from [<c0091f58>](warn_slowpath_common+0x4c/0x64)
> [<c0091f58>] (warn_slowpath_common+0x4c/0x64) from [<c0091f88>](warn_slowpath_null+0x18/0x1c)
> [<c0091f88>] (warn_slowpath_null+0x18/0x1c) from [<c024e610>](gpio_free+0x100/0x12c)
> [<c024e610>] (gpio_free+0x100/0x12c) from [<c03e9fbc>](ads7846_probe+0xa38/0xc5c)
> [<c03e9fbc>] (ads7846_probe+0xa38/0xc5c) from [<c02cff14>](spi_drv_probe+0x18/0x1c)
> [<c02cff14>] (spi_drv_probe+0x18/0x1c) from [<c028bca4>](driver_probe_device+0xc8/0x184)
> [<c028bca4>] (driver_probe_device+0xc8/0x184) from [<c028bdc8>](__driver_attach+0x68/0x8c)
> [<c028bdc8>] (__driver_attach+0x68/0x8c) from [<c028b4c8>](bus_for_each_dev+0x48/0x74)
> [<c028b4c8>] (bus_for_each_dev+0x48/0x74) from [<c028ae08>](bus_add_driver+0xa0/0x220)
> [<c028ae08>] (bus_add_driver+0xa0/0x220) from [<c028c0c0>](driver_register+0xa8/0x134)
> [<c028c0c0>] (driver_register+0xa8/0x134) from [<c0050550>](do_one_initcall+0xcc/0x1a4)
> [<c0050550>] (do_one_initcall+0xcc/0x1a4) from [<c00084e4>](kernel_init+0x14c/0x214)
> [<c00084e4>] (kernel_init+0x14c/0x214) from [<c005b494>](kernel_thread_exit+0x0/0x8)
> ---[ end trace 4053287f8a5ec18f ]---
>
> Initializing gpio_pendown in ads7846_probe to -1 before
> ads7846_setup_pendown function removes the above backtrace
> warning.
>
> Signed-off-by: Sourav Poddar <sourav.poddar@xxxxxx>
> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> ---
> drivers/input/touchscreen/ads7846.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
> index 14ea54b..036f245 100644
> --- a/drivers/input/touchscreen/ads7846.c
> +++ b/drivers/input/touchscreen/ads7846.c
> @@ -1221,6 +1221,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
> ts->input = input_dev;
> ts->vref_mv = pdata->vref_mv;
> ts->swap_xy = pdata->swap_xy;
> + ts->gpio_pendown = -1;
Going through the code, I see that ts->gpio_pendown is being filled
in ads7846_setup_pendown() which in turn is called by the
ads7846_probe().
Actually in ads7846_dev_init() [board-3430sdp.c], the gpio_pendown
pin has been requested already. The problem is with the following
line in ads7846_probe():
if (pdata->get_pendown_state) {
ts->get_pendown_state = pdata->get_pendown_state;
return 0;
}
Instead it should have been
if (pdata->get_pendown_state( )) {
ts->get_pendown_state = pdata->get_pendown_state;
return 0;
}
Also, filling ts->gpio_pendown = -1 should not be done in the driver file.
Instead pdata should either send a valid GPIO pin number or an -1
if it is not applicable to the board and this has to be done in the board file.
Also in board-3430sdp.c file, I observed that pdata->gpio_pendown
is not filled at all. But the ads7846_setup_pendown() in the driver relies
on pdata->gpio_pendown. This also needs to be fixed.
-V Charulatha
>
> mutex_init(&ts->lock);
> init_waitqueue_head(&ts->wait);
> --
> 1.7.0.4
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