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Message-Id: <2c839e9a-5b60-af90-40f1-df94c0112d95@linux.vnet.ibm.com>
Date: Mon, 4 Jun 2018 14:40:32 -0500
From: Eddie James <eajames@...ux.vnet.ibm.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: linux-i2c <linux-i2c@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
devicetree <devicetree@...r.kernel.org>,
Wolfram Sang <wsa@...-dreams.de>,
Rob Herring <robh+dt@...nel.org>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Joel Stanley <joel@....id.au>,
Mark Rutland <mark.rutland@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH v9 3/7] i2c: fsi: Add port structures
On 06/04/2018 02:17 PM, Andy Shevchenko wrote:
> On Mon, Jun 4, 2018 at 10:00 PM, Eddie James <eajames@...ux.vnet.ibm.com> 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@...ux.vnet.ibm.com>
>> ---
>> 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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