linux_dsm_epyc7002/drivers/i2c
Dmitry Osipenko ede2299f71 i2c: tegra: Support atomic transfers
System shutdown may happen with interrupts being disabled and in this case
kernel may hang if atomic transfer isn't supported by driver.

There were several occurrences where I found my Nexus 7 completely
discharged despite of being turned off and then one day I spotted this in
the log:

 reboot: Power down
 ------------[ cut here ]------------
 WARNING: CPU: 0 PID: 1 at drivers/i2c/i2c-core.h:40 i2c_transfer+0x95/0x9c
 No atomic I2C transfer handler for 'i2c-1'
 Modules linked in: tegra30_devfreq
 CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.4.0-next-20191202-00120-gf7ecd80fb803-dirty #3195
 Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
 [<c010e4b5>] (unwind_backtrace) from [<c010a0fd>] (show_stack+0x11/0x14)
 [<c010a0fd>] (show_stack) from [<c09995e5>] (dump_stack+0x85/0x94)
 [<c09995e5>] (dump_stack) from [<c011f3d1>] (__warn+0xc1/0xc4)
 [<c011f3d1>] (__warn) from [<c011f691>] (warn_slowpath_fmt+0x61/0x78)
 [<c011f691>] (warn_slowpath_fmt) from [<c069a8dd>] (i2c_transfer+0x95/0x9c)
 [<c069a8dd>] (i2c_transfer) from [<c05667f1>] (regmap_i2c_read+0x4d/0x6c)
 [<c05667f1>] (regmap_i2c_read) from [<c0563601>] (_regmap_raw_read+0x99/0x1cc)
 [<c0563601>] (_regmap_raw_read) from [<c0563757>] (_regmap_bus_read+0x23/0x38)
 [<c0563757>] (_regmap_bus_read) from [<c056293d>] (_regmap_read+0x3d/0xfc)
 [<c056293d>] (_regmap_read) from [<c0562d3b>] (_regmap_update_bits+0x87/0xc4)
 [<c0562d3b>] (_regmap_update_bits) from [<c0563add>] (regmap_update_bits_base+0x39/0x50)
 [<c0563add>] (regmap_update_bits_base) from [<c056fd39>] (max77620_pm_power_off+0x29/0x2c)
 [<c056fd39>] (max77620_pm_power_off) from [<c013bbdd>] (__do_sys_reboot+0xe9/0x170)
 [<c013bbdd>] (__do_sys_reboot) from [<c0101001>] (ret_fast_syscall+0x1/0x28)
 Exception stack(0xde907fa8 to 0xde907ff0)
 7fa0:                   00000000 00000000 fee1dead 28121969 4321fedc 00000000
 7fc0: 00000000 00000000 00000000 00000058 00000000 00000000 00000000 00000000
 7fe0: 0045adf0 bed9abb8 004444a0 b6c666d0
 ---[ end trace bdd18f87595b1a5e ]---

The atomic transferring is implemented by enforcing PIO mode for the
transfer and by polling interrupt status until transfer is completed or
failed.

Now system shuts down properly every time.

Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2020-01-15 18:32:08 +01:00
..
algos treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
busses i2c: tegra: Support atomic transfers 2020-01-15 18:32:08 +01:00
muxes i2c: Fix Kconfig indentation 2019-11-25 17:13:51 +01:00
i2c-boardinfo.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
i2c-core-acpi.c i2c: acpi: Force bus speed to 400KHz if a Silead touchscreen is present 2019-11-15 21:55:14 +01:00
i2c-core-base.c Merge branch 'i2c/for-current' into i2c/for-5.6 2020-01-15 18:31:37 +01:00
i2c-core-of.c Driver core patches for 5.5-rc1 2019-11-27 11:06:20 -08:00
i2c-core-slave.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
i2c-core-smbus.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
i2c-core.h Merge branch 'i2c/for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-07-15 21:10:39 -07:00
i2c-dev.c Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2019-06-02 10:18:11 -07:00
i2c-mux.c i2c: mux: add sysfs header 2019-06-22 07:32:33 +02:00
i2c-slave-eeprom.c i2c: slave-eeprom: Add read only mode 2019-09-28 20:44:12 +02:00
i2c-smbus.c i2c: smbus: Don't filter out duplicate alerts 2019-11-25 17:13:34 +01:00
i2c-stub.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
Kconfig docs: i2c: convert to ReST and add to driver-api bookset 2019-07-31 13:25:27 -06:00
Makefile i2c: don't use any __deprecated handling anymore 2018-08-24 17:26:43 +02:00