linux-kernel - Re: [PATCH v7 3/7] drivers/i2c: Add port structure to FSI algorithm

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Date:   Wed, 30 May 2018 02:19:25 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Eddie James <eajames@...ux.vnet.ibm.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>,
        "Edward A. James" <eajames@...ibm.com>
Subject: Re: [PATCH v7 3/7] drivers/i2c: Add port structure to FSI algorithm

On Wed, May 30, 2018 at 1:24 AM, Eddie James <eajames@...ux.vnet.ibm.com> wrote:
> From: "Edward A. James" <eajames@...ibm.com>
>
> Add and initialize I2C adapters for each port on the FSI-attached I2C
> master. Ports for each master are defined in the devicetree.

> +#include <linux/of.h>


> +static int fsi_i2c_set_port(struct fsi_i2c_port *port)
> +{
> +       int rc;
> +       struct fsi_device *fsi = port->master->fsi;
> +       u32 mode, dummy = 0;
> +       u16 old_port;
> +
> +       rc = fsi_i2c_read_reg(fsi, I2C_FSI_MODE, &mode);
> +       if (rc)
> +               return rc;
> +

> +       old_port = GETFIELD(I2C_MODE_PORT, mode);
> +
> +       if (old_port != port->port) {

Why not simple

if (port->port == GETFIELD())
  return 0;

?

> +               /* reset engine when port is changed */
> +               rc = fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy);
> +               if (rc)
> +                       return rc;
> +       }

> +       return rc;

It's hardly would be non-zero, right?

> +}

>  static int fsi_i2c_probe(struct device *dev)
>  {

Isn't below somehow repeats of_i2c_register_devices() ?
Why not to use it?

> +       /* 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 = devm_kzalloc(dev, 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);

> +                       devm_kfree(dev, port);

This hurts my eyes. Why?!

> +                       continue;
> +               }
> +
> +               list_add(&port->list, &i2c->ports);
> +       }
> +
>         dev_set_drvdata(dev, i2c);
>
>         return 0;
>  }

> +       if (!list_empty(&i2c->ports)) {

My gosh, this is done already in list_for_each*()

> +               list_for_each_entry(port, &i2c->ports, list) {
> +                       i2c_del_adapter(&port->adapter);
> +               }

> +       }



-- 
With Best Regards,
Andy Shevchenko