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d288a5712e
sdw_update_slave_status will be invoked when a codec is attached,
and the codec driver will initialize the codec with regmap functions
while the codec device is pm_runtime suspended.
regmap routines currently rely on regular SoundWire IO functions,
which will call pm_runtime_get_sync()/put_autosuspend.
This causes a deadlock where the resume routine waits for an
initialization complete signal that while the initialization complete
can only be reached when the resume completes.
The only solution if we allow regmap functions to be used in resume
operations as well as during codec initialization is to use _no_pm
routines. The duty of making sure the bus is operational needs to be
handled above the regmap level.
Fixes: 7c22ce6e21 ('regmap: Add SoundWire bus support')
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210122070634.12825-6-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright(c) 2015-17 Intel Corporation.
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/soundwire/sdw.h>
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#include "internal.h"
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static int regmap_sdw_write(void *context, unsigned int reg, unsigned int val)
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{
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struct device *dev = context;
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struct sdw_slave *slave = dev_to_sdw_dev(dev);
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return sdw_write_no_pm(slave, reg, val);
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}
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static int regmap_sdw_read(void *context, unsigned int reg, unsigned int *val)
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{
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struct device *dev = context;
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struct sdw_slave *slave = dev_to_sdw_dev(dev);
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int read;
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read = sdw_read_no_pm(slave, reg);
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if (read < 0)
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return read;
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*val = read;
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return 0;
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}
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static struct regmap_bus regmap_sdw = {
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.reg_read = regmap_sdw_read,
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.reg_write = regmap_sdw_write,
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.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
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.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
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};
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static int regmap_sdw_config_check(const struct regmap_config *config)
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{
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/* All register are 8-bits wide as per MIPI Soundwire 1.0 Spec */
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if (config->val_bits != 8)
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return -ENOTSUPP;
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/* Registers are 32 bits wide */
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if (config->reg_bits != 32)
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return -ENOTSUPP;
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if (config->pad_bits != 0)
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return -ENOTSUPP;
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return 0;
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}
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struct regmap *__regmap_init_sdw(struct sdw_slave *sdw,
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const struct regmap_config *config,
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struct lock_class_key *lock_key,
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const char *lock_name)
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{
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int ret;
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ret = regmap_sdw_config_check(config);
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if (ret)
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return ERR_PTR(ret);
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return __regmap_init(&sdw->dev, ®map_sdw,
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&sdw->dev, config, lock_key, lock_name);
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}
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EXPORT_SYMBOL_GPL(__regmap_init_sdw);
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struct regmap *__devm_regmap_init_sdw(struct sdw_slave *sdw,
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const struct regmap_config *config,
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struct lock_class_key *lock_key,
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const char *lock_name)
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{
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int ret;
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ret = regmap_sdw_config_check(config);
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if (ret)
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return ERR_PTR(ret);
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return __devm_regmap_init(&sdw->dev, ®map_sdw,
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&sdw->dev, config, lock_key, lock_name);
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}
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EXPORT_SYMBOL_GPL(__devm_regmap_init_sdw);
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MODULE_DESCRIPTION("Regmap SoundWire Module");
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MODULE_LICENSE("GPL v2");
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