[PATCH v2 13/14] spi/of: Create new device registration method and accessors

[PATCH v2 13/14] spi/of: Create new device registration method and accessors

[Grant Likely]

From: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>

Dynamically inserting spi device nodes requires the use of a single
device registration method. Refactor the existing
of_register_spi_devices() to split out the core functionality for a
single device into a separate function; of_register_spi_device(). This
function will be used by the OF_DYNAMIC overlay code to make live
modifications to the tree.

Methods to lookup a device/master using a device node are added
as well, of_find_spi_master_by_node() & of_find_spi_device_by_node().

Changes since v1:
* Brown paper bug with parameter on of_register_spi_device().

Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
[grant.likely] Split patch into two pieces for clarity
Signed-off-by: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: <linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
---
 drivers/spi/spi.c | 222 +++++++++++++++++++++++++++++-------------------------
 1 file changed, 118 insertions(+), 104 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index ebcb33df2eb2..a3557c57d4f7 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1220,6 +1220,121 @@ err_init_queue:
 /*-------------------------------------------------------------------------*/
 
 #if defined(CONFIG_OF)
+static struct spi_device *
+of_register_spi_device(struct spi_master *master, struct device_node *nc)
+{
+	struct spi_device *spi;
+	int rc;
+	u32 value;
+
+	/* Alloc an spi_device */
+	spi = spi_alloc_device(master);
+	if (!spi) {
+		dev_err(&master->dev, "spi_device alloc error for %s\n",
+			nc->full_name);
+		rc = -ENOMEM;
+		goto err_out;
+	}
+
+	/* Select device driver */
+	rc = of_modalias_node(nc, spi->modalias,
+				sizeof(spi->modalias));
+	if (rc < 0) {
+		dev_err(&master->dev, "cannot find modalias for %s\n",
+			nc->full_name);
+		goto err_out;
+	}
+
+	/* Device address */
+	rc = of_property_read_u32(nc, "reg", &value);
+	if (rc) {
+		dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
+			nc->full_name, rc);
+		goto err_out;
+	}
+	spi->chip_select = value;
+
+	/* Mode (clock phase/polarity/etc.) */
+	if (of_find_property(nc, "spi-cpha", NULL))
+		spi->mode |= SPI_CPHA;
+	if (of_find_property(nc, "spi-cpol", NULL))
+		spi->mode |= SPI_CPOL;
+	if (of_find_property(nc, "spi-cs-high", NULL))
+		spi->mode |= SPI_CS_HIGH;
+	if (of_find_property(nc, "spi-3wire", NULL))
+		spi->mode |= SPI_3WIRE;
+	if (of_find_property(nc, "spi-lsb-first", NULL))
+		spi->mode |= SPI_LSB_FIRST;
+
+	/* Device DUAL/QUAD mode */
+	if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
+		switch (value) {
+		case 1:
+			break;
+		case 2:
+			spi->mode |= SPI_TX_DUAL;
+			break;
+		case 4:
+			spi->mode |= SPI_TX_QUAD;
+			break;
+		default:
+			dev_warn(&master->dev,
+				"spi-tx-bus-width %d not supported\n",
+				value);
+			break;
+		}
+	}
+
+	if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
+		switch (value) {
+		case 1:
+			break;
+		case 2:
+			spi->mode |= SPI_RX_DUAL;
+			break;
+		case 4:
+			spi->mode |= SPI_RX_QUAD;
+			break;
+		default:
+			dev_warn(&master->dev,
+				"spi-rx-bus-width %d not supported\n",
+				value);
+			break;
+		}
+	}
+
+	/* Device speed */
+	rc = of_property_read_u32(nc, "spi-max-frequency", &value);
+	if (rc) {
+		dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
+			nc->full_name, rc);
+		goto err_out;
+	}
+	spi->max_speed_hz = value;
+
+	/* IRQ */
+	spi->irq = irq_of_parse_and_map(nc, 0);
+
+	/* Store a pointer to the node in the device structure */
+	of_node_get(nc);
+	spi->dev.of_node = nc;
+
+	/* Register the new device */
+	request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
+	rc = spi_add_device(spi);
+	if (rc) {
+		dev_err(&master->dev, "spi_device register error %s\n",
+			nc->full_name);
+		goto err_out;
+	}
+
+	return spi;
+
+err_out:
+	spi_dev_put(spi);
+	return ERR_PTR(rc);
+}
+
 /**
  * of_register_spi_devices() - Register child devices onto the SPI bus
  * @master:	Pointer to spi_master device
@@ -1231,116 +1346,15 @@ static void of_register_spi_devices(struct spi_master *master)
 {
 	struct spi_device *spi;
 	struct device_node *nc;
-	int rc;
-	u32 value;
 
 	if (!master->dev.of_node)
 		return;
 
 	for_each_available_child_of_node(master->dev.of_node, nc) {
-		/* Alloc an spi_device */
-		spi = spi_alloc_device(master);
-		if (!spi) {
-			dev_err(&master->dev, "spi_device alloc error for %s\n",
+		spi = of_register_spi_device(master, nc);
+		if (IS_ERR(spi))
+			dev_warn(&master->dev, "Failed to create SPI device for %s\n",
 				nc->full_name);
-			spi_dev_put(spi);
-			continue;
-		}
-
-		/* Select device driver */
-		if (of_modalias_node(nc, spi->modalias,
-				     sizeof(spi->modalias)) < 0) {
-			dev_err(&master->dev, "cannot find modalias for %s\n",
-				nc->full_name);
-			spi_dev_put(spi);
-			continue;
-		}
-
-		/* Device address */
-		rc = of_property_read_u32(nc, "reg", &value);
-		if (rc) {
-			dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
-				nc->full_name, rc);
-			spi_dev_put(spi);
-			continue;
-		}
-		spi->chip_select = value;
-
-		/* Mode (clock phase/polarity/etc.) */
-		if (of_find_property(nc, "spi-cpha", NULL))
-			spi->mode |= SPI_CPHA;
-		if (of_find_property(nc, "spi-cpol", NULL))
-			spi->mode |= SPI_CPOL;
-		if (of_find_property(nc, "spi-cs-high", NULL))
-			spi->mode |= SPI_CS_HIGH;
-		if (of_find_property(nc, "spi-3wire", NULL))
-			spi->mode |= SPI_3WIRE;
-		if (of_find_property(nc, "spi-lsb-first", NULL))
-			spi->mode |= SPI_LSB_FIRST;
-
-		/* Device DUAL/QUAD mode */
-		if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
-			switch (value) {
-			case 1:
-				break;
-			case 2:
-				spi->mode |= SPI_TX_DUAL;
-				break;
-			case 4:
-				spi->mode |= SPI_TX_QUAD;
-				break;
-			default:
-				dev_warn(&master->dev,
-					 "spi-tx-bus-width %d not supported\n",
-					 value);
-				break;
-			}
-		}
-
-		if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
-			switch (value) {
-			case 1:
-				break;
-			case 2:
-				spi->mode |= SPI_RX_DUAL;
-				break;
-			case 4:
-				spi->mode |= SPI_RX_QUAD;
-				break;
-			default:
-				dev_warn(&master->dev,
-					 "spi-rx-bus-width %d not supported\n",
-					 value);
-				break;
-			}
-		}
-
-		/* Device speed */
-		rc = of_property_read_u32(nc, "spi-max-frequency", &value);
-		if (rc) {
-			dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
-				nc->full_name, rc);
-			spi_dev_put(spi);
-			continue;
-		}
-		spi->max_speed_hz = value;
-
-		/* IRQ */
-		spi->irq = irq_of_parse_and_map(nc, 0);
-
-		/* Store a pointer to the node in the device structure */
-		of_node_get(nc);
-		spi->dev.of_node = nc;
-
-		/* Register the new device */
-		request_module("%s%s", SPI_MODULE_PREFIX, spi->modalias);
-		rc = spi_add_device(spi);
-		if (rc) {
-			dev_err(&master->dev, "spi_device register error %s\n",
-				nc->full_name);
-			spi_dev_put(spi);
-		}
-
 	}
 }
 #else
-- 
1.9.1

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[PATCH v2 14/14] spi/of: Add OF notifier handler

[Grant Likely]

From: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>

Add OF notifier handler needed for creating/destroying spi devices
according to dynamic runtime changes in the DT live tree. This code is
enabled when CONFIG_OF_DYNAMIC is selected.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou-OWPKS81ov/FWk0Htik3J/w@public.gmane.org>
Signed-off-by: Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: <linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
---
 drivers/spi/spi.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a3557c57d4f7..bf1cab0fad66 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2317,6 +2317,86 @@ EXPORT_SYMBOL_GPL(spi_write_then_read);
 
 /*-------------------------------------------------------------------------*/
 
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+static int __spi_of_device_match(struct device *dev, void *data)
+{
+	return dev->of_node == data;
+}
+
+/* must call put_device() when done with returned spi_device device */
+static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
+{
+	struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
+						__spi_of_device_match);
+	return dev ? to_spi_device(dev) : NULL;
+}
+
+static int __spi_of_master_match(struct device *dev, const void *data)
+{
+	return dev->of_node == data;
+}
+
+/* the spi masters are not using spi_bus, so we find it with another way */
+static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
+{
+	struct device *dev;
+
+	dev = class_find_device(&spi_master_class, NULL, node,
+				__spi_of_master_match);
+	if (!dev)
+		return NULL;
+
+	/* reference got in class_find_device */
+	return container_of(dev, struct spi_master, dev);
+}
+
+static int of_spi_notify(struct notifier_block *nb, unsigned long action,
+			 void *arg)
+{
+	struct of_reconfig_data *rd = arg;
+	struct spi_master *master;
+	struct spi_device *spi;
+
+	switch (of_reconfig_get_state_change(action, arg)) {
+	case OF_RECONFIG_CHANGE_ADD:
+		master = of_find_spi_master_by_node(rd->dn->parent);
+		if (master == NULL)
+			return NOTIFY_OK;	/* not for us */
+
+		spi = of_register_spi_device(master, rd->dn);
+		put_device(&master->dev);
+
+		if (IS_ERR(spi)) {
+			pr_err("%s: failed to create for '%s'\n",
+					__func__, rd->dn->full_name);
+			return notifier_from_errno(PTR_ERR(spi));
+		}
+		break;
+
+	case OF_RECONFIG_CHANGE_REMOVE:
+		/* find our device by node */
+		spi = of_find_spi_device_by_node(rd->dn);
+		if (spi == NULL)
+			return NOTIFY_OK;	/* no? not meant for us */
+
+		/* unregister takes one ref away */
+		spi_unregister_device(spi);
+
+		/* and put the reference of the find */
+		put_device(&spi->dev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block spi_of_notifier = {
+	.notifier_call = of_spi_notify,
+};
+#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
+extern struct notifier_block spi_of_notifier;
+#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
+
 static int __init spi_init(void)
 {
 	int	status;
@@ -2334,6 +2414,10 @@ static int __init spi_init(void)
 	status = class_register(&spi_master_class);
 	if (status < 0)
 		goto err2;
+
+	if (IS_ENABLED(CONFIG_OF))
+		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
+
 	return 0;
 
 err2:
-- 
1.9.1

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Re: [PATCH v2 13/14] spi/of: Create new device registration method and accessors

[Mark Brown]

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On Mon, Nov 24, 2014 at 10:33:41PM +0000, Grant Likely wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> Dynamically inserting spi device nodes requires the use of a single
> device registration method. Refactor the existing
> of_register_spi_devices() to split out the core functionality for a
> single device into a separate function; of_register_spi_device(). This
> function will be used by the OF_DYNAMIC overlay code to make live
> modifications to the tree.
> 
> Methods to lookup a device/master using a device node are added
> as well, of_find_spi_master_by_node() & of_find_spi_device_by_node().
> 
> Changes since v1:
> * Brown paper bug with parameter on of_register_spi_device().

Please don't include things like this in the commit message, if you want
to include a changelog put it after the --- like SubmittingPatches says.
Once it's in mainline this is just noise.

Otherwise

Reviewed-by: Mark Brown <broonie@kernel.org>

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Re: [PATCH v2 14/14] spi/of: Add OF notifier handler

[Mark Brown]

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On Mon, Nov 24, 2014 at 10:33:42PM +0000, Grant Likely wrote:
> From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
> 
> Add OF notifier handler needed for creating/destroying spi devices
> according to dynamic runtime changes in the DT live tree. This code is
> enabled when CONFIG_OF_DYNAMIC is selected.

Reviwed-by: Mark Brown <broonei@kernel.org>

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