[PATCH v2 08/18] drivers/fsi: Implement slave initialisation

From: christopher . lee . bostic
Date: Thu Jan 12 2017 - 17:29:14 EST


From: Jeremy Kerr <jk@xxxxxxxxxx>

Create fsi_slave devices during the master scan.

Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
Signed-off-by: Chris Bostic <cbostic@xxxxxxxxxx>
---
drivers/fsi/fsi-core.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 2 deletions(-)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index 5f9f7a9..931bcba 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -17,10 +17,15 @@
#include <linux/fsi.h>
#include <linux/module.h>
#include <linux/idr.h>
+#include <linux/crc-fsi.h>
+#include <linux/slab.h>

#include "fsi-master.h"

#define FSI_N_SLAVES 4
+#define FSI_SLAVE_CONF_CRC_SHIFT 4
+#define FSI_SLAVE_CONF_CRC_MASK 0x0000000f
+#define FSI_SLAVE_CONF_DATA_BITS 28

static DEFINE_IDA(master_ida);

@@ -34,12 +39,59 @@ struct fsi_slave {
#define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)

/* FSI slave support */
+
+static void fsi_slave_release(struct device *dev)
+{
+ struct fsi_slave *slave = to_fsi_slave(dev);
+
+ kfree(slave);
+}
+
static int fsi_slave_init(struct fsi_master *master,
int link, uint8_t slave_id)
{
- /* todo: initialise slave device, perform engine scan */
+ struct fsi_slave *slave;
+ uint32_t chip_id;
+ int rc;
+ uint8_t crc;
+
+ rc = master->read(master, link, slave_id, 0, &chip_id, sizeof(chip_id));
+ if (rc) {
+ dev_warn(master->dev, "can't read slave %02x:%02x: %d\n",
+ link, slave_id, rc);
+ return -ENODEV;
+ }
+ crc = crc_fsi(0, chip_id >> FSI_SLAVE_CONF_CRC_SHIFT,
+ FSI_SLAVE_CONF_DATA_BITS);
+ if (crc != (chip_id & FSI_SLAVE_CONF_CRC_MASK)) {
+ dev_warn(master->dev, "slave %02x:%02x invalid chip id CRC!\n",
+ link, slave_id);
+ return -EIO;
+ }
+
+ pr_debug("fsi: found chip %08x at %02x:%02x:%02x\n",
+ master->idx, chip_id, link, slave_id);
+
+ /* we can communicate with a slave; create devices and scan */
+ slave = kzalloc(sizeof(*slave), GFP_KERNEL);
+ if (!slave)
+ return -ENOMEM;
+
+ slave->master = master;
+ slave->id = slave_id;
+ slave->dev.parent = master->dev;
+ slave->dev.release = fsi_slave_release;
+
+ dev_set_name(&slave->dev, "slave@%02x:%02x", link, slave_id);
+ rc = device_register(&slave->dev);
+ if (rc < 0) {
+ dev_warn(master->dev, "failed to create slave device: %d\n",
+ rc);
+ put_device(&slave->dev);
+ return rc;
+ }

- return -ENODEV;
+ return rc;
}

/* FSI master support */
--
1.8.2.2