[3.13.y.z extended stable] Patch "iio: adc: at91_adc: Repair broken platform_data support" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    iio: adc: at91_adc: Repair broken platform_data support

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.3.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 6d706b76d7c18bcbd441cd80e4b40dff59825f8e Mon Sep 17 00:00:00 2001
From: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Date: Sat, 3 May 2014 16:57:00 +0100
Subject: iio: adc: at91_adc: Repair broken platform_data support

commit 467a44b0372d8268ce5bd90e58bde7db51c1d476 upstream.

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: c46016665fff (iio: at91: ADC start-up time calculation changed since at91sam9x5)

Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
Tested-by: Josh Wu <josh.wu at atmel.com>
Acked-by: Josh Wu <josh.wu at atmel.com>
Signed-off-by: Jonathan Cameron <jic23 at kernel.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/iio/adc/at91_adc.c | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 5b1aa02..bbba014 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -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),
--
1.9.1