soundwire: add Slave sysfs support

Expose MIPI DisCo Slave properties in sysfs.

For Slave properties and Data Port 0, the attributes are managed with
simple devm_ support.

A Slave Device may have more than one Data Port (DPN), and each Data
Port can be sink or source. The attributes are created dynamically
using pre-canned macros, but still use devm_ with a name attribute
group to avoid creating kobjects - as requested by GregKH. In the
_show function, we use container_of() to retrieve port number and
direction required to extract the information.

Audio modes are not supported for now. Depending on the discussions
the SoundWire Device Class, we may add it later as is or follow the
new specification.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20200518203551.2053-4-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 215 insertions, 0 deletions

diff --git a/drivers/soundwire/sysfs_slave.c b/drivers/soundwire/sysfs_slave.c
new file mode 100644
index 000000000000..ae6d241eca50
--- /dev/null
+++ b/drivers/soundwire/sysfs_slave.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright(c) 2015-2020 Intel Corporation.
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/soundwire/sdw.h>
+#include <linux/soundwire/sdw_type.h>
+#include "bus.h"
+#include "sysfs_local.h"
+
+/*
+ * Slave sysfs
+ */
+
+/*
+ * The sysfs for Slave reflects the MIPI description as given
+ * in the MIPI DisCo spec
+ *
+ * Base file is device
+ *	|---- modalias
+ *	|---- dev-properties
+ *		|---- mipi_revision
+ *		|---- wake_capable
+ *		|---- test_mode_capable
+ *		|---- clk_stop_mode1
+ *		|---- simple_clk_stop_capable
+ *		|---- clk_stop_timeout
+ *		|---- ch_prep_timeout
+ *		|---- reset_behave
+ *		|---- high_PHY_capable
+ *		|---- paging_support
+ *		|---- bank_delay_support
+ *		|---- p15_behave
+ *		|---- master_count
+ *		|---- source_ports
+ *		|---- sink_ports
+ *	|---- dp0
+ *		|---- max_word
+ *		|---- min_word
+ *		|---- words
+ *		|---- BRA_flow_controlled
+ *		|---- simple_ch_prep_sm
+ *		|---- imp_def_interrupts
+ *	|---- dpN_<sink/src>
+ *		|---- max_word
+ *		|---- min_word
+ *		|---- words
+ *		|---- type
+ *		|---- max_grouping
+ *		|---- simple_ch_prep_sm
+ *		|---- ch_prep_timeout
+ *		|---- imp_def_interrupts
+ *		|---- min_ch
+ *		|---- max_ch
+ *		|---- channels
+ *		|---- ch_combinations
+ *		|---- max_async_buffer
+ *		|---- block_pack_mode
+ *		|---- port_encoding
+ *
+ */
+
+#define sdw_slave_attr(field, format_string)			\
+static ssize_t field##_show(struct device *dev,			\
+			    struct device_attribute *attr,	\
+			    char *buf)				\
+{								\
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);		\
+	return sprintf(buf, format_string, slave->prop.field);	\
+}								\
+static DEVICE_ATTR_RO(field)
+
+sdw_slave_attr(mipi_revision, "0x%x\n");
+sdw_slave_attr(wake_capable, "%d\n");
+sdw_slave_attr(test_mode_capable, "%d\n");
+sdw_slave_attr(clk_stop_mode1, "%d\n");
+sdw_slave_attr(simple_clk_stop_capable, "%d\n");
+sdw_slave_attr(clk_stop_timeout, "%d\n");
+sdw_slave_attr(ch_prep_timeout, "%d\n");
+sdw_slave_attr(reset_behave, "%d\n");
+sdw_slave_attr(high_PHY_capable, "%d\n");
+sdw_slave_attr(paging_support, "%d\n");
+sdw_slave_attr(bank_delay_support, "%d\n");
+sdw_slave_attr(p15_behave, "%d\n");
+sdw_slave_attr(master_count, "%d\n");
+sdw_slave_attr(source_ports, "0x%x\n");
+sdw_slave_attr(sink_ports, "0x%x\n");
+
+static ssize_t modalias_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+
+	return sdw_slave_modalias(slave, buf, 256);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static struct attribute *slave_attrs[] = {
+	&dev_attr_modalias.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(slave);
+
+static struct attribute *slave_dev_attrs[] = {
+	&dev_attr_mipi_revision.attr,
+	&dev_attr_wake_capable.attr,
+	&dev_attr_test_mode_capable.attr,
+	&dev_attr_clk_stop_mode1.attr,
+	&dev_attr_simple_clk_stop_capable.attr,
+	&dev_attr_clk_stop_timeout.attr,
+	&dev_attr_ch_prep_timeout.attr,
+	&dev_attr_reset_behave.attr,
+	&dev_attr_high_PHY_capable.attr,
+	&dev_attr_paging_support.attr,
+	&dev_attr_bank_delay_support.attr,
+	&dev_attr_p15_behave.attr,
+	&dev_attr_master_count.attr,
+	&dev_attr_source_ports.attr,
+	&dev_attr_sink_ports.attr,
+	NULL,
+};
+
+/*
+ * we don't use ATTRIBUTES_GROUP here since we want to add a subdirectory
+ * for device-level properties
+ */
+static struct attribute_group sdw_slave_dev_attr_group = {
+	.attrs	= slave_dev_attrs,
+	.name = "dev-properties",
+};
+
+/*
+ * DP0 sysfs
+ */
+
+#define sdw_dp0_attr(field, format_string)				\
+static ssize_t field##_show(struct device *dev,				\
+			    struct device_attribute *attr,		\
+			    char *buf)					\
+{									\
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);			\
+	return sprintf(buf, format_string, slave->prop.dp0_prop->field);\
+}									\
+static DEVICE_ATTR_RO(field)
+
+sdw_dp0_attr(max_word, "%d\n");
+sdw_dp0_attr(min_word, "%d\n");
+sdw_dp0_attr(BRA_flow_controlled, "%d\n");
+sdw_dp0_attr(simple_ch_prep_sm, "%d\n");
+sdw_dp0_attr(imp_def_interrupts, "0x%x\n");
+
+static ssize_t words_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct sdw_slave *slave = dev_to_sdw_dev(dev);
+	ssize_t size = 0;
+	int i;
+
+	for (i = 0; i < slave->prop.dp0_prop->num_words; i++)
+		size += sprintf(buf + size, "%d ",
+				slave->prop.dp0_prop->words[i]);
+	size += sprintf(buf + size, "\n");
+
+	return size;
+}
+static DEVICE_ATTR_RO(words);
+
+static struct attribute *dp0_attrs[] = {
+	&dev_attr_max_word.attr,
+	&dev_attr_min_word.attr,
+	&dev_attr_words.attr,
+	&dev_attr_BRA_flow_controlled.attr,
+	&dev_attr_simple_ch_prep_sm.attr,
+	&dev_attr_imp_def_interrupts.attr,
+	NULL,
+};
+
+/*
+ * we don't use ATTRIBUTES_GROUP here since we want to add a subdirectory
+ * for dp0-level properties
+ */
+static const struct attribute_group dp0_group = {
+	.attrs = dp0_attrs,
+	.name = "dp0",
+};
+
+int sdw_slave_sysfs_init(struct sdw_slave *slave)
+{
+	int ret;
+
+	ret = devm_device_add_groups(&slave->dev, slave_groups);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_device_add_group(&slave->dev, &sdw_slave_dev_attr_group);
+	if (ret < 0)
+		return ret;
+
+	if (slave->prop.dp0_prop) {
+		ret = devm_device_add_group(&slave->dev, &dp0_group);
+		if (ret < 0)
+			return ret;
+	}
+
+	if (slave->prop.source_ports || slave->prop.sink_ports) {
+		ret = sdw_slave_sysfs_dpn_init(slave);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+