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

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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




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