[alsa-devel] [PATCH v1] ASoC: tlv320aic32x4: handle regmap_read error gracefully

[Peter Seiderer]

Fixes:

[    5.169310] Division by zero in kernel.
[    5.200998] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.3.18-20191021-1+ #14
[    5.203049] cdc_acm 2-1.6:1.0: ttyACM0: USB ACM device
[    5.208198] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
[    5.220084] Backtrace:
[    5.222628] [<8010f60c>] (dump_backtrace) from [<8010f9a8>] (show_stack+0x20/0x24)
[    5.230348]  r7:810a1c6c r6:00000000 r5:60000013 r4:810a1c6c
[    5.236097] [<8010f988>] (show_stack) from [<809e06a0>] (dump_stack+0xac/0xd8)
[    5.243469] [<809e05f4>] (dump_stack) from [<8010f780>] (__div0+0x24/0x28)
[    5.250431]  r9:8111adc8 r8:ae631180 r7:aebd27c0 r6:ae631e40 r5:00000000 r4:81006508
[    5.258325] [<8010f75c>] (__div0) from [<809de7ac>] (Ldiv0+0x8/0x10)
[    5.264841] [<8085c7e0>] (clk_aic32x4_div_recalc_rate) from [<805ba70c>] (__clk_register+0x2f8/0x7e4)
[    5.274141]  r5:80dd065c r4:ae6bd480
[    5.277869] [<805ba414>] (__clk_register) from [<805bace0>] (devm_clk_register+0x58/0x8c)
[    5.286130]  r10:81006508 r9:810946d4 r8:00000000 r7:ae8de1c0 r6:ae631ac0 r5:ae631e40
[    5.294103]  r4:ae8d8020
[    5.296724] [<805bac88>] (devm_clk_register) from [<8085cea8>] (aic32x4_register_clocks+0x120/0x14c)
[    5.306004]  r7:ae8de1c0 r6:ae8d8020 r5:ae631e40 r4:810946c0
[    5.311818] [<8085cd88>] (aic32x4_register_clocks) from [<8085bf60>] (aic32x4_probe+0x94/0x468)
[    5.320602]  r10:81094730 r9:00000000 r8:af361fc0 r7:bfd6d040 r6:00000000 r5:ae8d8020
[    5.328574]  r4:af361e40
[    5.331195] [<8085becc>] (aic32x4_probe) from [<8085cf60>] (aic32x4_i2c_probe+0x6c/0x88)
[    5.339434]  r8:00000000 r7:ae8d8000 r6:81094730 r5:ae8d8000 r4:81006508
[    5.346288] [<8085cef4>] (aic32x4_i2c_probe) from [<807554b0>] (i2c_device_probe+0x2ac/0x2f0)
[    5.354894]  r5:8085cef4 r4:ae8d8020
[    5.358625] [<80755204>] (i2c_device_probe) from [<80678e34>] (really_probe+0x11c/0x428)
[    5.366802]  r9:00000000 r8:810b3e78 r7:00000000 r6:8111e020 r5:ae8d8020 r4:8111e01c
[    5.374694] [<80678d18>] (really_probe) from [<80679388>] (driver_probe_device+0x88/0x1e0)
[    5.383106]  r10:80f63860 r9:ffffe000 r8:ffffe000 r7:80679794 r6:81094730 r5:81094730
[    5.391080]  r4:ae8d8020
[    5.393702] [<80679300>] (driver_probe_device) from [<8067978c>] (device_driver_attach+0x68/0x70)
[    5.402724]  r9:ffffe000 r8:ffffe000 r7:80679794 r6:81094730 r5:00000000 r4:ae8d8020
[    5.410555] [<80679724>] (device_driver_attach) from [<80679858>] (__driver_attach+0xc4/0x164)
[    5.419313]  r7:80679794 r6:ae8d8020 r5:81094730 r4:00000000
[    5.425123] [<80679794>] (__driver_attach) from [<80676a14>] (bus_for_each_dev+0x84/0xc4)
[    5.433384]  r7:80679794 r6:81094730 r5:81006508 r4:ae8dc0c0
[    5.439192] [<80676990>] (bus_for_each_dev) from [<80678668>] (driver_attach+0x2c/0x30)
[    5.447279]  r7:00000000 r6:af361500 r5:8107fd94 r4:81094730
[    5.453087] [<8067863c>] (driver_attach) from [<80677fc4>] (bus_add_driver+0x1d0/0x210)
[    5.461240] [<80677df4>] (bus_add_driver) from [<80679f34>] (driver_register+0x84/0x118)
[    5.469414]  r7:00000000 r6:80f4ac9c r5:81006508 r4:81094730
[    5.475224] [<80679eb0>] (driver_register) from [<80755dfc>] (i2c_register_driver+0x4c/0xb8)
[    5.483807]  r5:81006508 r4:81094714
[    5.487472] [<80755db0>] (i2c_register_driver) from [<80f4acc0>] (aic32x4_i2c_driver_init+0x24/0x28)
[    5.496750]  r5:81006508 r4:810a7180
[    5.500415] [<80f4ac9c>] (aic32x4_i2c_driver_init) from [<80103288>] (do_one_initcall+0x64/0x2d0)
[    5.509442] [<80103224>] (do_one_initcall) from [<80f014a8>] (kernel_init_freeable+0x300/0x390)
[    5.518287]  r8:810c7300 r7:810c7300 r6:00000007 r5:80f920c4 r4:80f63840
[    5.525079] [<80f011a8>] (kernel_init_freeable) from [<809f892c>] (kernel_init+0x18/0x124)
[    5.533490]  r10:00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:809f8914
[    5.541461]  r4:00000000
[    5.544084] [<809f8914>] (kernel_init) from [<801010b4>] (ret_from_fork+0x14/0x20)
[    5.551800] Exception stack(0xaf115fb0 to 0xaf115ff8)
[    5.556935] 5fa0:                                     00000000 00000000 00000000 00000000
[    5.565262] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    5.573522] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    5.580283]  r5:809f8914 r4:00000000

Signed-off-by: Peter Seiderer <ps.report at gmx.net>
---
 sound/soc/codecs/tlv320aic32x4-clk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/codecs/tlv320aic32x4-clk.c b/sound/soc/codecs/tlv320aic32x4-clk.c
index 156c153c12ab..7a82e3448780 100644
--- a/sound/soc/codecs/tlv320aic32x4-clk.c
+++ b/sound/soc/codecs/tlv320aic32x4-clk.c
@@ -338,7 +338,8 @@ static unsigned long clk_aic32x4_div_recalc_rate(struct clk_hw *hw,
 
 	unsigned int val;
 
-	regmap_read(div->regmap, div->reg, &val);
+	if (regmap_read(div->regmap, div->reg, &val))
+		return 0;
 
 	return DIV_ROUND_UP(parent_rate, val & AIC32X4_DIV_MASK);
 }
-- 
2.24.0