Re: [PATCH 16/16] drivers/fsi: Add GPIO based FSI master

On Thu, Dec 8, 2016 at 10:12 PM, Jeremy Kerr [off-list ref] wrote:

Hi Chris,

quoted

+static ssize_t store_scan(struct device *dev,
+                             struct device_attribute *attr,
+                             const char *buf,
+                             size_t count)
+{
+     struct fsi_master_gpio *master = dev_get_drvdata(dev);
+
+     fsi_master_gpio_init(master);
+
+     /* clear out any old scan data if present */
+     fsi_master_unregister(&master->master);
+     fsi_master_register(&master->master);
+
+     return count;
+}
+
+static DEVICE_ATTR(scan, 0200, NULL, store_scan);

I think it would make more sense to have the scan attribute populated by
the fsi core; we want this on all masters, not just GPIO.

Hi Jeremy,

Sure, will move that to the core.

Currently, the only GPIO-master-specific functionality here is the
fsi_master_gpio_init() - but isn't this something that we can do at
probe time instead?

Yes that can be done at probe time.  Will change.

quoted

+static int fsi_master_gpio_probe(struct platform_device *pdev)
+{
+     struct fsi_master_gpio *master;
+     struct gpio_desc *gpio;
+
+     master = devm_kzalloc(&pdev->dev, sizeof(*master), GFP_KERNEL);
+     if (!master)
+             return -ENOMEM;

We should be populating master->dev.parent, see

  https://github.com/jk-ozlabs/linux/commit/5225d6c47

Will make the change.

quoted

+     /* Optional pins */
+
+     gpio = devm_gpiod_get(&pdev->dev, "trans", 0);
+     if (IS_ERR(gpio))
+             dev_dbg(&pdev->dev, "probe: failed to get trans pin\n");
+     else
+             master->gpio_trans = gpio;

I found devm_gpiod_get_optional(), which might make this a little
neater.

Will make this change.


Thanks,
Chris

Cheers,


Jeremy

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