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Date: Thu, 16 Nov 2017 22:19:44 +0530
From: Vinod Koul <vinod.koul@...el.com>
To: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
LKML <linux-kernel@...r.kernel.org>,
ALSA <alsa-devel@...a-project.org>, Mark <broonie@...nel.org>,
Takashi <tiwai@...e.de>,
Pierre <pierre-louis.bossart@...ux.intel.com>,
Sanyog Kale <sanyog.r.kale@...el.com>,
Shreyas NC <shreyas.nc@...el.com>, patches.audio@...el.com,
alan@...ux.intel.com,
Charles Keepax <ckeepax@...nsource.cirrus.com>,
Sagar Dharia <sdharia@...eaurora.org>, plai@...eaurora.org,
Sudheer Papothi <spapothi@...eaurora.org>
Subject: Re: [PATCH v2 03/14] soundwire: Add Master registration
On Thu, Nov 16, 2017 at 04:05:22PM +0000, Srinivas Kandagatla wrote:
>
>
> On 10/11/17 11:49, Vinod Koul wrote:
> >A Master registers with SoundWire bus and scans the firmware provided
> >for device description. In this patch we scan the ACPI namespaces and
> >create the SoundWire Slave devices based on the ACPI description
> >
> >Signed-off-by: Sanyog Kale <sanyog.r.kale@...el.com>
> >Signed-off-by: Vinod Koul <vinod.koul@...el.com>
> >---
> > drivers/soundwire/Makefile | 2 +-
> > drivers/soundwire/bus.c | 163 +++++++++++++++++++++++++++++++++++++++
> > drivers/soundwire/bus.h | 20 +++++
> > drivers/soundwire/slave.c | 172 ++++++++++++++++++++++++++++++++++++++++++
> > include/linux/soundwire/sdw.h | 11 +++
> > 5 files changed, 367 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/soundwire/bus.c
> > create mode 100644 drivers/soundwire/slave.c
> >
> >diff --git a/drivers/soundwire/Makefile b/drivers/soundwire/Makefile
> >index d1281def7662..c875e434f8b3 100644
> >--- a/drivers/soundwire/Makefile
> >+++ b/drivers/soundwire/Makefile
> >@@ -3,5 +3,5 @@
> > #
> > #Bus Objs
> >-soundwire-bus-objs := bus_type.o
> >+soundwire-bus-objs := bus_type.o bus.o slave.o
>
> >+
> >+#include <linux/delay.h>
> >+#include <linux/device.h>
> >+#include <linux/pm_runtime.h>
> Does this belong to this patch.
Not really, tahnks for spotting
>
> >+#include <linux/soundwire/sdw.h>
> >+#include "bus.h"
> >+
> >+/**
> >+ * sdw_add_bus_master: add a bus Master instance
> >+ *
> >+ * @bus: bus instance
> >+ *
> >+ * Initializes the bus instance, read properties and create child
> >+ * devices.
> >+ */
> >+int sdw_add_bus_master(struct sdw_bus *bus)
> >+{
> >+ int ret;
> >+
> >+ if (!bus->dev) {
> >+ pr_err("SoundWire bus has no device");
> >+ return -ENODEV;
> >+ }
> >+
> >+ mutex_init(&bus->bus_lock);
> >+ INIT_LIST_HEAD(&bus->slaves);
> >+
> >+ /*
> >+ * Enumeration device number and broadcast device number are
> >+ * not used for assignment so mask these and other higher bits
> >+ */
> >+
> >+ /* Set higher order bits */
> >+ *bus->assigned = ~GENMASK(SDW_BROADCAST_DEV_NUM, SDW_ENUM_DEV_NUM);
> Can't we use ida for this.
> This would also cut down code added for allocating dev_num.
Device numbers in SoundWire are 0 thru 15 with 0 and 15 having special
meaning so can'r be allocated. Bitmaps give me a nice way to ensure we dont
use those by masking these and above 15... IDR uses bitmap with stuff on top
which maynot be helpful here as I need a number 1 to 14. For a generic, give
me a number IDRs are very useful.
>
> >+
> >+ /* Set device number and broadcast device number */
> >+ set_bit(SDW_ENUM_DEV_NUM, bus->assigned);
> >+ set_bit(SDW_BROADCAST_DEV_NUM, bus->assigned);
>
> >+ return 0;
> >+}
> >+EXPORT_SYMBOL(sdw_add_bus_master);
> >+
> >+static int sdw_delete_slave(struct device *dev, void *data)
> >+{
> >+ struct sdw_slave *slave = dev_to_sdw_dev(dev);
> >+ struct sdw_bus *bus = slave->bus;
> >+
> >+ mutex_lock(&bus->bus_lock);
> >+
> >+ if (slave->dev_num) /* clear dev_num if assigned */
> >+ clear_bit(slave->dev_num, bus->assigned);
> >+
> >+ list_del_init(&slave->node);
> >+ mutex_unlock(&bus->bus_lock);
> >+
> >+ device_unregister(dev);
> >+ return 0;
> >+}
> >+
> >+void sdw_delete_bus_master(struct sdw_bus *bus)
> >+{
> >+ device_for_each_child(bus->dev, NULL, sdw_delete_slave);
> >+}
> >+EXPORT_SYMBOL(sdw_delete_bus_master);
> No kerneldoc..??
will add.
>
> >+
> diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
> >new file mode 100644
> >index 000000000000..4bf2a6cf732c
> >--- /dev/null
> >+++ b/drivers/soundwire/slave.c
>
> >+
> >+#include <linux/acpi.h>
> >+#include <linux/init.h>
> >+#include <linux/soundwire/sdw.h>
> >+#include "bus.h"
> >+
> >+}
> >+
> >+static int sdw_slave_add(struct sdw_bus *bus,
> >+ struct sdw_slave_id *id, struct fwnode_handle *fwnode)
> >+{
> >+ struct sdw_slave *slave;
> >+ int ret;
> >+
> >+ slave = kzalloc(sizeof(*slave), GFP_KERNEL);
> >+ if (!slave)
> >+ return -ENOMEM;
> >+
> >+ /* Initialize data structure */
> >+ memcpy(&slave->id, id, sizeof(*id));
> >+ slave->dev.parent = bus->dev;
> >+ slave->dev.fwnode = fwnode;
> >+
> >+ /* name shall be sdw:link:mfg:part:class:unique */
> >+ dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x:%x",
> >+ bus->link_id, id->mfg_id, id->part_id,
> >+ id->class_id, id->unique_id);
> >+
> >+ slave->dev.release = sdw_slave_release;
> >+ slave->dev.bus = &sdw_bus_type;
> >+ slave->bus = bus;
> >+ slave->status = SDW_SLAVE_UNATTACHED;
> >+ slave->dev_num = 0;
> >+
> >+ mutex_lock(&bus->bus_lock);
> >+ list_add_tail(&slave->node, &bus->slaves);
> >+ mutex_unlock(&bus->bus_lock);
> >+
> >+ ret = device_register(&slave->dev);
> >+ if (ret) {
> >+ dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
> >+
> >+ /*
> >+ * On err, don't free but drop ref as this will be freed
> >+ * when release method is invoked.
> >+ */
> >+ mutex_lock(&bus->bus_lock);
> >+ list_del(&slave->node);
> >+ mutex_unlock(&bus->bus_lock);
> >+ put_device(&slave->dev);
> >+ return ret;
>
> remove this line and ..
> >+ }
> >+
> >+ return 0;
>
> return ret;
better :)
> >+#if IS_ENABLED(CONFIG_OF)
> >+int sdw_of_find_slaves(struct sdw_bus *bus)
> >+{
> >+ /* placeholder now, fill on OF support */
> >+ return -ENOTSUPP;
> >+}
> >+#endif
>
> We should probably remove this dummy function, and add this functionality
> later.
this was kept for people to know how they may add DT support, but yes its
better to remove.
--
~Vinod
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