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![Pierre-Louis Bossart](/assets/img/avatar_default.png)
The 'master' device acts as a glue layer used during bus
initialization only, and it needs to be 'transparent' for pm_runtime
management. Its behavior should be that it becomes active when one of
its children becomes active, and suspends when all of its children are
suspended.
In our tests on Intel platforms, we routinely see these sort of
warnings on the initial boot:
[ 21.447345] rt715 sdw:3:25d:715:0: runtime PM trying to activate
child device sdw:3:25d:715:0 but parent (sdw-master-3) is not active
This is root-caused to a missing setup to make the device 'active' on
probe. Since we don't want the device to remain active forever after
the probe, the autosuspend configuration is also enabled at the end of
the probe - the device will actually autosuspend only in the case
where there are no devices physically attached. In practice, the
master device will suspend when all its children are no longer active.
Fixes: bd84256e86
('soundwire: master: enable pm runtime')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20201124130742.10986-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
188 lines
4.8 KiB
C
188 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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// Copyright(c) 2019-2020 Intel Corporation.
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#include <linux/device.h>
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#include <linux/acpi.h>
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#include <linux/pm_runtime.h>
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#include <linux/soundwire/sdw.h>
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#include <linux/soundwire/sdw_type.h>
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#include "bus.h"
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/*
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* The 3s value for autosuspend will only be used if there are no
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* devices physically attached on a bus segment. In practice enabling
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* the bus operation will result in children devices become active and
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* the master device will only suspend when all its children are no
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* longer active.
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*/
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#define SDW_MASTER_SUSPEND_DELAY_MS 3000
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/*
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* The sysfs for properties reflects the MIPI description as given
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* in the MIPI DisCo spec
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*
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* Base file is:
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* sdw-master-N
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* |---- revision
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* |---- clk_stop_modes
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* |---- max_clk_freq
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* |---- clk_freq
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* |---- clk_gears
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* |---- default_row
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* |---- default_col
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* |---- dynamic_shape
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* |---- err_threshold
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*/
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#define sdw_master_attr(field, format_string) \
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static ssize_t field##_show(struct device *dev, \
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struct device_attribute *attr, \
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char *buf) \
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{ \
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struct sdw_master_device *md = dev_to_sdw_master_device(dev); \
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return sprintf(buf, format_string, md->bus->prop.field); \
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} \
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static DEVICE_ATTR_RO(field)
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sdw_master_attr(revision, "0x%x\n");
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sdw_master_attr(clk_stop_modes, "0x%x\n");
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sdw_master_attr(max_clk_freq, "%d\n");
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sdw_master_attr(default_row, "%d\n");
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sdw_master_attr(default_col, "%d\n");
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sdw_master_attr(default_frame_rate, "%d\n");
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sdw_master_attr(dynamic_frame, "%d\n");
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sdw_master_attr(err_threshold, "%d\n");
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static ssize_t clock_frequencies_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct sdw_master_device *md = dev_to_sdw_master_device(dev);
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ssize_t size = 0;
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int i;
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for (i = 0; i < md->bus->prop.num_clk_freq; i++)
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size += sprintf(buf + size, "%8d ",
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md->bus->prop.clk_freq[i]);
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size += sprintf(buf + size, "\n");
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return size;
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}
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static DEVICE_ATTR_RO(clock_frequencies);
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static ssize_t clock_gears_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct sdw_master_device *md = dev_to_sdw_master_device(dev);
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ssize_t size = 0;
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int i;
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for (i = 0; i < md->bus->prop.num_clk_gears; i++)
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size += sprintf(buf + size, "%8d ",
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md->bus->prop.clk_gears[i]);
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size += sprintf(buf + size, "\n");
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return size;
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}
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static DEVICE_ATTR_RO(clock_gears);
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static struct attribute *master_node_attrs[] = {
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&dev_attr_revision.attr,
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&dev_attr_clk_stop_modes.attr,
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&dev_attr_max_clk_freq.attr,
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&dev_attr_default_row.attr,
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&dev_attr_default_col.attr,
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&dev_attr_default_frame_rate.attr,
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&dev_attr_dynamic_frame.attr,
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&dev_attr_err_threshold.attr,
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&dev_attr_clock_frequencies.attr,
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&dev_attr_clock_gears.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(master_node);
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static void sdw_master_device_release(struct device *dev)
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{
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struct sdw_master_device *md = dev_to_sdw_master_device(dev);
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kfree(md);
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}
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static const struct dev_pm_ops master_dev_pm = {
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SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend,
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pm_generic_runtime_resume, NULL)
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};
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struct device_type sdw_master_type = {
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.name = "soundwire_master",
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.release = sdw_master_device_release,
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.pm = &master_dev_pm,
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};
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/**
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* sdw_master_device_add() - create a Linux Master Device representation.
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* @bus: SDW bus instance
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* @parent: parent device
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* @fwnode: firmware node handle
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*/
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int sdw_master_device_add(struct sdw_bus *bus, struct device *parent,
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struct fwnode_handle *fwnode)
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{
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struct sdw_master_device *md;
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int ret;
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if (!parent)
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return -EINVAL;
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md = kzalloc(sizeof(*md), GFP_KERNEL);
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if (!md)
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return -ENOMEM;
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md->dev.bus = &sdw_bus_type;
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md->dev.type = &sdw_master_type;
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md->dev.parent = parent;
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md->dev.groups = master_node_groups;
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md->dev.of_node = parent->of_node;
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md->dev.fwnode = fwnode;
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md->dev.dma_mask = parent->dma_mask;
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dev_set_name(&md->dev, "sdw-master-%d", bus->id);
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ret = device_register(&md->dev);
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if (ret) {
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dev_err(parent, "Failed to add master: ret %d\n", ret);
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/*
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* On err, don't free but drop ref as this will be freed
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* when release method is invoked.
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*/
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put_device(&md->dev);
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goto device_register_err;
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}
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/* add shortcuts to improve code readability/compactness */
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md->bus = bus;
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bus->dev = &md->dev;
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bus->md = md;
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pm_runtime_set_autosuspend_delay(&bus->md->dev, SDW_MASTER_SUSPEND_DELAY_MS);
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pm_runtime_use_autosuspend(&bus->md->dev);
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pm_runtime_mark_last_busy(&bus->md->dev);
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pm_runtime_set_active(&bus->md->dev);
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pm_runtime_enable(&bus->md->dev);
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pm_runtime_idle(&bus->md->dev);
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device_register_err:
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return ret;
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}
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/**
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* sdw_master_device_del() - delete a Linux Master Device representation.
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* @bus: bus handle
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*
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* This function is the dual of sdw_master_device_add()
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*/
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int sdw_master_device_del(struct sdw_bus *bus)
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{
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pm_runtime_disable(&bus->md->dev);
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device_unregister(bus->dev);
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return 0;
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}
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