When SPI is used for control, the driver must hold the SPI bus lock
while issuing the sequence of writes to perform a soft reset.
>From the time the driver writes the SYSTEM_RESET command until the
driver does a write to terminate the reset, there must not be any
activity on the SPI bus lines. If there is any SPI activity during the
soft-reset, another soft-reset will be triggered. The state of the SPI
chip select is irrelevant.
A repeated soft-reset does not in itself cause any problems, and it is
not an infinite loop. The problem is a race between these resets and
the driver polling for boot completion. There is a time window between
soft resets where the driver could read HALO_STATE as 2 (fully booted)
while the chip is actually soft-resetting. Although this window is
small, it is long enough that it is possible to hit it in normal
operation.
To prevent this race and ensure the chip really is fully booted, the
driver calls spi_bus_lock() to prevent other activity while resetting.
It then issues the SYSTEM_RESET mailbox command. After allowing
sufficient time for reset to take effect, the driver issues a PING
mailbox command, which will force completion of the full soft-reset
sequence. The SPI bus lock can then be released. The mailbox is
checked for any boot or wakeup response from the firmware, before the
value in HALO_STATE will be trusted.
This does not affect SoundWire or I2C control.
Fixes: 8a731fd37f ("ASoC: cs35l56: Move utility functions to shared file")
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://patch.msgid.link/20250225131843.113752-3-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
The irq member was being set before calling the init function and then
cs35l56_irq_request() was called only when the init was successful.
However cs35l56_release() calls devm_free_irq() when the irq member is
set and therefore if init() fails then this will cause an attempted free
of an unallocated IRQ.
Instead pass the desired IRQ number to the cs35l56_irq_request()
function and set cs35l56->irq only when it has been successfully
allocated.
Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/168147949598.26.711670799488943454@mailman-core.alsa-project.org
Signed-off-by: Mark Brown <broonie@kernel.org>
The CS35L56 combines a high-performance mono audio amplifier, Class-H
tracking inductive boost converter, Halo Core(TM) DSP and a DC-DC boost
converter supporting Class-H tracking.
Supported control interfaces are I2C, SPI or SoundWire.
Supported audio interfaces are I2S/TDM or SoundWire.
Most chip functionality is controlled by on-board ROM firmware that is
always running. The driver must apply patch/tune to the firmware
before using the CS35L56.
Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20230320112245.115720-9-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
