Re: [PATCH v9 3/7] i2c: fsi: Add port structures

From: Eddie James
Date: Mon Jun 04 2018 - 15:40:49 EST




On 06/04/2018 02:17 PM, Andy Shevchenko wrote:
On Mon, Jun 4, 2018 at 10:00 PM, Eddie James <eajames@xxxxxxxxxxxxxxxxxx> wrote:
Add and initialize I2C adapters for each port on the FSI-attached I2C
master. Ports for each master are defined in the devicetree.

Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-fsi.c | 90 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 90 insertions(+)

diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
index e1b183c..12130c3 100644
--- a/drivers/i2c/busses/i2c-fsi.c
+++ b/drivers/i2c/busses/i2c-fsi.c
@@ -17,7 +17,10 @@
#include <linux/fsi.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
+#include <linux/list.h>
#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/slab.h>

#define FSI_ENGID_I2C 0x7

@@ -123,6 +126,14 @@
struct fsi_i2c_master {
struct fsi_device *fsi;
u8 fifo_size;
+ struct list_head ports;
+};
+
+struct fsi_i2c_port {
+ struct list_head list;
+ struct i2c_adapter adapter;
+ struct fsi_i2c_master *master;
+ u16 port;
};

static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
@@ -176,9 +187,38 @@ static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c)
return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_WATER_MARK, &watermark);
}

+static int fsi_i2c_set_port(struct fsi_i2c_port *port)
+{
+ int rc;
+ struct fsi_device *fsi = port->master->fsi;
+ u32 mode, dummy = 0;
+
+ rc = fsi_i2c_read_reg(fsi, I2C_FSI_MODE, &mode);
+ if (rc)
+ return rc;
+
+ if (FIELD_GET(I2C_MODE_PORT, mode) == port->port)
+ return 0;
+
+ mode = (mode & ~I2C_MODE_PORT) | FIELD_PREP(I2C_MODE_PORT, port->port);
Did you consider to split this to two lines / assignments?

It fit on one line (< 80 chars) so I left it as-is...


+ rc = fsi_i2c_write_reg(fsi, I2C_FSI_MODE, &mode);
+ if (rc)
+ return rc;
+
+ /* reset engine when port is changed */
+ return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);
+}
+
static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
+ int rc;
+ struct fsi_i2c_port *port = adap->algo_data;
+
+ rc = fsi_i2c_set_port(port);
+ if (rc)
+ return rc;
+
return -EOPNOTSUPP;
}

@@ -196,23 +236,72 @@ static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
static int fsi_i2c_probe(struct device *dev)
{
struct fsi_i2c_master *i2c;
+ struct fsi_i2c_port *port;
+ struct device_node *np;
int rc;
+ u32 port_no;

i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c)
return -ENOMEM;

i2c->fsi = to_fsi_dev(dev);
+ INIT_LIST_HEAD(&i2c->ports);

rc = fsi_i2c_dev_init(i2c);
if (rc)
return rc;

+ /* Add adapter for each i2c port of the master. */
+ for_each_available_child_of_node(dev->of_node, np) {
+ rc = of_property_read_u32(np, "reg", &port_no);
+ if (rc || port_no > USHRT_MAX)
+ continue;


+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port)
+ break;
+
+ port->master = i2c;
+ port->port = port_no;
+
+ port->adapter.owner = THIS_MODULE;
+ port->adapter.dev.of_node = np;
+ port->adapter.dev.parent = dev;
+ port->adapter.algo = &fsi_i2c_algorithm;
+ port->adapter.algo_data = port;
+
+ snprintf(port->adapter.name, sizeof(port->adapter.name),
+ "i2c_bus-%u", port_no);
+
+ rc = i2c_add_adapter(&port->adapter);
+ if (rc < 0) {
+ dev_err(dev, "Failed to register adapter: %d\n", rc);
+ kfree(port);
+ continue;
+ }
+
+ list_add(&port->list, &i2c->ports);
+ }
+
dev_set_drvdata(dev, i2c);

return 0;
}

+static int fsi_i2c_remove(struct device *dev)
+{
+ struct fsi_i2c_master *i2c = dev_get_drvdata(dev);
+ struct fsi_i2c_port *port;
+
+ list_for_each_entry(port, &i2c->ports, list) {
+ i2c_del_adapter(&port->adapter);
+ kfree(port);
+ }
Just to be sure, it will be called if and only if all adapters are not
busy. Correct?

If I understand the code and comments correctly, i2c_del_adapter will block until all references to the adapter device are gone. So, should be safe to free it now.

Thanks,
Eddie


+
+ return 0;
+}
+
static const struct fsi_device_id fsi_i2c_ids[] = {
{ FSI_ENGID_I2C, FSI_VERSION_ANY },
{ 0 }
@@ -224,6 +313,7 @@ static int fsi_i2c_probe(struct device *dev)
.name = "i2c-fsi",
.bus = &fsi_bus_type,
.probe = fsi_i2c_probe,
+ .remove = fsi_i2c_remove,
},
};

--
1.8.3.1