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Commit 467a44b0 authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Jonathan Cameron
Browse files

iio: adc: at91_adc: Repair broken platform_data support 



Trying to use the at91_adc driver while not using device tree is ending up in a
kernel crash:

Unable to handle kernel NULL pointer dereference at virtual address 00000004
[...]
[<c01f3510>] (at91_adc_probe) from [<c0183828>] (platform_drv_probe+0x18/0x48)
[<c0183828>] (platform_drv_probe) from [<c01824a4>] (driver_probe_device+0x100/0x218)
[<c01824a4>] (driver_probe_device) from [<c0182648>] (__driver_attach+0x8c/0x90)
[<c0182648>] (__driver_attach) from [<c0180de4>] (bus_for_each_dev+0x58/0x88)
[<c0180de4>] (bus_for_each_dev) from [<c0181c7c>] (bus_add_driver+0xd4/0x1d4)
[<c0181c7c>] (bus_add_driver) from [<c0182c40>] (driver_register+0x78/0xf4)
[<c0182c40>] (driver_register) from [<c0008998>] (do_one_initcall+0xe8/0x14c)
[<c0008998>] (do_one_initcall) from [<c02f0b50>] (kernel_init_freeable+0xec/0x1b4)
[<c02f0b50>] (kernel_init_freeable) from [<c022acdc>] (kernel_init+0x8/0xe4)
[<c022acdc>] (kernel_init) from [<c0009670>] (ret_from_fork+0x14/0x24)

This is because the at91_adc_caps structure is mandatory but is not filled when
using platform_data. Correct that by using an id_table. It ensues that the
driver will not match "at91_adc" anymore but it was crashing anyway.

Fixes: c4601666 (iio: at91: ADC start-up time calculation changed since at91sam9x5)
Cc: stable@vger.kernel.org # v3.13+

Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: default avatarJosh Wu <josh.wu@atmel.com>
Acked-by: default avatarJosh Wu <josh.wu@atmel.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 084b6e77

drivers/iio/adc/at91_adc.c

+22 −4
Original line number Diff line number Diff line
@@ -765,14 +765,17 @@ static int at91_adc_probe_pdata(struct at91_adc_state *st, 
	if (!pdata)

		return -EINVAL;



	st->caps = (struct at91_adc_caps *)

			platform_get_device_id(pdev)->driver_data;



	st->use_external = pdata->use_external_triggers;

	st->vref_mv = pdata->vref;

	st->channels_mask = pdata->channels_used;

	st->num_channels = pdata->num_channels;

	st->num_channels = st->caps->num_channels;

	st->startup_time = pdata->startup_time;

	st->trigger_number = pdata->trigger_number;

	st->trigger_list = pdata->trigger_list;

	st->registers = pdata->registers;

	st->registers = &st->caps->registers;



	return 0;

}
@@ -1101,7 +1104,6 @@ static int at91_adc_remove(struct platform_device *pdev) 
	return 0;

}



#ifdef CONFIG_OF

static struct at91_adc_caps at91sam9260_caps = {

	.calc_startup_ticks = calc_startup_ticks_9260,

	.num_channels = 4,
@@ -1154,11 +1156,27 @@ static const struct of_device_id at91_adc_dt_ids[] = { 
	{},

};

MODULE_DEVICE_TABLE(of, at91_adc_dt_ids);

#endif



static const struct platform_device_id at91_adc_ids[] = {

	{

		.name = "at91sam9260-adc",

		.driver_data = (unsigned long)&at91sam9260_caps,

	}, {

		.name = "at91sam9g45-adc",

		.driver_data = (unsigned long)&at91sam9g45_caps,

	}, {

		.name = "at91sam9x5-adc",

		.driver_data = (unsigned long)&at91sam9x5_caps,

	}, {

		/* terminator */

	}

};

MODULE_DEVICE_TABLE(platform, at91_adc_ids);



static struct platform_driver at91_adc_driver = {

	.probe = at91_adc_probe,

	.remove = at91_adc_remove,

	.id_table = at91_adc_ids,

	.driver = {

		   .name = DRIVER_NAME,

		   .of_match_table = of_match_ptr(at91_adc_dt_ids),