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soundwire: cadence_master: add hw_reset capability in debugfs

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Provide debugfs capability to kick link and devices into hard-reset
(as defined by MIPI). This capability is really useful when some
devices are no longer responsive and/or to check the software handling
of resynchronization.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191022235448.17586-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Pierre-Louis Bossart 2019-10-22 18:54:45 -05:00 committed by Vinod Koul
parent 49ea07d33d
commit 675d4c9aba
1 changed files with 23 additions and 0 deletions
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23
drivers/soundwire/cadence_master.c
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@ -333,6 +333,26 @@ static int cdns_reg_show(struct seq_file *s, void *data)
}
DEFINE_SHOW_ATTRIBUTE(cdns_reg);
static int cdns_hw_reset(void *data, u64 value)
{
struct sdw_cdns *cdns = data;
int ret;
if (value != 1)
return -EINVAL;
/* Userspace changed the hardware state behind the kernel's back */
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
ret = sdw_cdns_exit_reset(cdns);
dev_dbg(cdns->dev, "link hw_reset done: %d\n", ret);
return ret;
}
DEFINE_DEBUGFS_ATTRIBUTE(cdns_hw_reset_fops, NULL, cdns_hw_reset, "%llu\n");
/**
* sdw_cdns_debugfs_init() - Cadence debugfs init
* @cdns: Cadence instance
@ -341,6 +361,9 @@ DEFINE_SHOW_ATTRIBUTE(cdns_reg);
void sdw_cdns_debugfs_init(struct sdw_cdns *cdns, struct dentry *root)
{
debugfs_create_file("cdns-registers", 0400, root, cdns, &cdns_reg_fops);
debugfs_create_file("cdns-hw-reset", 0200, root, cdns,
&cdns_hw_reset_fops);
}
EXPORT_SYMBOL_GPL(sdw_cdns_debugfs_init);