linux-kernel - [PATCH] dmaengine: edma: Add dummy driver skeleton for edma3-tptc

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Date:	Mon, 2 Nov 2015 15:21:40 +0200
From:	Peter Ujfalusi <peter.ujfalusi@...com>
To:	<vinod.koul@...el.com>, <nsekhar@...com>, <olof@...om.net>
CC:	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<dmaengine@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<tony@...mide.com>, <t-kristo@...com>
Subject: [PATCH] dmaengine: edma: Add dummy driver skeleton for edma3-tptc

The eDMA3 TPTC does not need any software configuration, but it is a
separate IP block in the SoC. In order the omap hwmod core to be able to
handle the TPTC resources correctly in regards of PM we need to have a
driver loaded for it.
This patch will add a dummy driver skeleton without probe or remove
callbacks provided.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
Reported-by: Olof Johansson <olof@...om.net>
---
Hi,

while it would have been possible to add the edma3-tptc compatible to be handled
by the edma-tpcc driver (and when the device is tptc, do nothing) it would
make the driver code a bit harder to follow.
I think having separate structure for the tptc looks better and if we ever need
to have separate driver for the tptc it will be cleaner for us the separate it.

This patch alone w/o any hwmod flag changes will make sure that the edma-tptc is
not powered down after the kernel is finished it's booting.

Regards,
Peter

 drivers/dma/edma.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 31722d436a42..6b03e4e84e6b 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -269,6 +269,11 @@ static const struct of_device_id edma_of_ids[] = {
 	{}
 };
 
+static const struct of_device_id edma_tptc_of_ids[] = {
+	{ .compatible = "ti,edma3-tptc", },
+	{}
+};
+
 static inline unsigned int edma_read(struct edma_cc *ecc, int offset)
 {
 	return (unsigned int)__raw_readl(ecc->base + offset);
@@ -2399,6 +2404,13 @@ static struct platform_driver edma_driver = {
 	},
 };
 
+static struct platform_driver edma_tptc_driver = {
+	.driver = {
+		.name	= "edma3-tptc",
+		.of_match_table = edma_tptc_of_ids,
+	},
+};
+
 bool edma_filter_fn(struct dma_chan *chan, void *param)
 {
 	bool match = false;
@@ -2418,6 +2430,12 @@ EXPORT_SYMBOL(edma_filter_fn);
 
 static int edma_init(void)
 {
+	int ret;
+
+	ret = platform_driver_register(&edma_tptc_driver);
+	if (ret)
+		return ret;
+
 	return platform_driver_register(&edma_driver);
 }
 subsys_initcall(edma_init);
@@ -2425,6 +2443,7 @@ subsys_initcall(edma_init);
 static void __exit edma_exit(void)
 {
 	platform_driver_unregister(&edma_driver);
+	platform_driver_unregister(&edma_tptc_driver);
 }
 module_exit(edma_exit);
 
-- 
2.6.1

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