From: Jonathan Cameron <jic23@kernel.org>
To: Sanchayan Maity <maitysanchayan@gmail.com>
Cc: stefan@agner.ch, b38611@freescale.com, linux-iio@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: adc: vf610_adc: Fix division by zero error
Date: Sun, 25 Oct 2015 12:20:54 +0000 [thread overview]
Message-ID: <562CC926.1080700@kernel.org> (raw)
In-Reply-To: <0dafb77d1c3f7cd1b6de59a619b45a80c00169d5.1445240424.git.maitysanchayan@gmail.com>
On 19/10/15 08:43, Sanchayan Maity wrote:
> In case the fsl,adck-max-frequency property is not present in
> the device tree, a division by zero error results during the
> probe call on kernel boot (see below). This patch fixes it and
> also restores device tree compatibility in case kernels are
> booting with old device trees without this property specified.
>
> [ 1.063229] Division by zero in kernel.
> [ 1.067152] CPU: 0 PID: 1 Comm: swapper Not tainted
> 4.3.0-rc5-00212-gcc88cef #37
> [ 1.074650] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
> [ 1.081135] Backtrace:
> [ 1.083694] [<800134a4>] (dump_backtrace) from [<8001369c>]
> (show_stack+0x18/0x1c)
> [ 1.091340] r7:00000008 r6:8e0ae210 r5:00000000 r4:8e299800
> [ 1.097146] [<80013684>] (show_stack) from [<80297b1c>]
> (dump_stack+0x24/0x28)
> [ 1.104483] [<80297af8>] (dump_stack) from [<80013608>]
> (__div0+0x1c/0x20)
> [ 1.111421] [<800135ec>] (__div0) from [<802968b4>] (Ldiv0+0x8/0x10)
> [ 1.117865] [<80424350>] (vf610_adc_probe) from [<803153b4>]
> (platform_drv_probe+0x4c/0xac)
> [ 1.126311] r10:00000000 r9:8076a5ec r8:00000000 r7:fffffdfb
> r6:807cc67c r5:8e0ae210
> [ 1.134319] r4:807f6c54
> [ 1.136915] [<80315368>] (platform_drv_probe) from [<803138bc>]
> (driver_probe_device+0x20c/0x2f8)
> [ 1.145882] r7:807cc67c r6:00000000 r5:8e0ae210 r4:807f6c54
> [ 1.151657] [<803136b0>] (driver_probe_device) from [<80313a3c>]
> (__driver_attach+0x94/0x98)
> [ 1.160190] r9:8076a5ec r8:00000098 r7:00000000 r6:8e0ae244
> r5:807cc67c r4:8e0ae210
> [ 1.168112] [<803139a8>] (__driver_attach) from [<80311cb8>]
> (bus_for_each_dev+0x70/0xa4)
> [ 1.176383] r7:00000000 r6:803139a8 r5:807cc67c r4:00000000
> [ 1.182159] [<80311c48>] (bus_for_each_dev) from [<80313318>]
> (driver_attach+0x24/0x28)
> [ 1.190260] r6:807bb568 r5:8e2a5b00 r4:807cc67c
> [ 1.194996] [<803132f4>] (driver_attach) from [<80312f50>]
> (bus_add_driver+0x1a4/0x21c)
> [ 1.203113] [<80312dac>] (bus_add_driver) from [<803142a8>]
> (driver_register+0x80/0x100)
> [ 1.211275] r7:8e2a7dc0 r6:807a8160 r5:80789e14 r4:807cc67c
> [ 1.217075] [<80314228>] (driver_register) from [<803152f8>]
> (__platform_driver_register+0x5c/0x64)
> [ 1.226216] r5:80789e14 r4:807a8160
> [ 1.229877] [<8031529c>] (__platform_driver_register) from
> [<80789e30>] (vf610_adc_driver_init+0x1c/0x20)
> [ 1.239556] [<80789e14>] (vf610_adc_driver_init) from [<800095f8>]
> (do_one_initcall+0x94/0x1dc)
> [ 1.248365] [<80009564>] (do_one_initcall) from [<8076ae34>]
> (kernel_init_freeable+0x13c/0x1e0)
> [ 1.257155] r10:80794830 r9:8076a5ec r8:00000098 r7:807d5780
> r6:807d5780 r5:00000006
> [ 1.265153] r4:807a0ee8
> [ 1.267753] [<8076acf8>] (kernel_init_freeable) from [<80590ef0>]
> (kernel_init+0x18/0xf0)
> [ 1.276021] r10:00000000 r9:00000000 r8:00000000 r7:00000000
> r6:00000000 r5:80590ed8
> [ 1.284015] r4:807d5780
> [ 1.286615] [<80590ed8>] (kernel_init) from [<8000f878>]
> (ret_from_fork+0x14/0x3c)
> [ 1.294278] r5:80590ed8 r4:00000000
>
> Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
I'd like an ack from Fugang on this as I'm less than entirely
sure what the current logic is doing!
Jonathan
> ---
> drivers/iio/adc/vf610_adc.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c
> index 6bf4c20..bf4f3d8 100644
> --- a/drivers/iio/adc/vf610_adc.c
> +++ b/drivers/iio/adc/vf610_adc.c
> @@ -193,6 +193,8 @@ static inline void vf610_adc_calculate_rates(struct vf610_adc *info)
> adc_feature->clk_div = 8;
> }
>
> + adck_rate = ipg_rate / info->adc_feature.clk_div;
> +
> /*
> * Determine the long sample time adder value to be used based
> * on the default minimum sample time provided.
> @@ -217,7 +219,6 @@ static inline void vf610_adc_calculate_rates(struct vf610_adc *info)
> * BCT (Base Conversion Time): fixed to 25 ADCK cycles for 12 bit mode
> * LSTAdder(Long Sample Time): 3, 5, 7, 9, 13, 17, 21, 25 ADCK cycles
> */
> - adck_rate = ipg_rate / info->adc_feature.clk_div;
> for (i = 0; i < ARRAY_SIZE(vf610_hw_avgs); i++)
> info->sample_freq_avail[i] =
> adck_rate / (6 + vf610_hw_avgs[i] *
>
next prev parent reply other threads:[~2015-10-25 12:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 7:43 [PATCH] iio: adc: vf610_adc: Fix division by zero error Sanchayan Maity
2015-10-25 12:20 ` Jonathan Cameron [this message]
2015-10-26 16:21 ` Stefan Agner
2015-10-31 9:33 ` Jonathan Cameron
2015-10-26 10:33 ` Duan Andy
2015-10-26 10:33 ` Duan Andy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=562CC926.1080700@kernel.org \
--to=jic23@kernel.org \
--cc=b38611@freescale.com \
--cc=linux-iio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=maitysanchayan@gmail.com \
--cc=stefan@agner.ch \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.