mtd: nand: atmel_nand: retrieve NFC clock

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=2d405ec5fdd5b6848beb820301d4fcaa3e2c4159
Commit:     2d405ec5fdd5b6848beb820301d4fcaa3e2c4159
Parent:     55ab9ec99bbfb4450dfa9bc0fd9e2c5052f4c3f7
Author:     Boris BREZILLON <boris.brezillon at free-electrons.com>
AuthorDate: Sat Sep 13 01:23:59 2014 +0200
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Wed Sep 17 00:45:11 2014 -0700

    mtd: nand: atmel_nand: retrieve NFC clock
    
    Retrieve the NFC clock to make sure it is enabled. Make that optional to ensure
    compatibility with previous device trees but document it as mandatory so newer
    device trees will include it.
    
    Signed-off-by: Boris BREZILLON <boris.brezillon at free-electrons.com>
    Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
    Acked-by: Josh Wu <josh.wu at atmel.com>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 .../devicetree/bindings/mtd/atmel-nand.txt         |  2 ++
 drivers/mtd/nand/atmel_nand.c                      | 25 ++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
index c472883..6edc3b6 100644
--- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
@@ -36,6 +36,7 @@ Optional properties:
     - reg : should specify the address and size used for NFC command registers,
             NFC registers and NFC Sram. NFC Sram address and size can be absent
             if don't want to use it.
+    - clocks: phandle to the peripheral clock
   - Optional properties:
     - atmel,write-by-sram: boolean to enable NFC write by sram.
 
@@ -98,6 +99,7 @@ nand0: nand at 40000000 {
 		compatible = "atmel,sama5d3-nfc";
 		#address-cells = <1>;
 		#size-cells = <1>;
+		clocks = <&hsmc_clk>
 		reg = <
 			0x70000000 0x10000000	/* NFC Command Registers */
 			0xffffc000 0x00000070	/* NFC HSMC regs */
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 9c5f717..d1e502f 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -27,6 +27,7 @@
  *
  */
 
+#include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -96,6 +97,8 @@ struct atmel_nfc {
 	bool			use_nfc_sram;
 	bool			write_by_sram;
 
+	struct clk		*clk;
+
 	bool			is_initialized;
 	struct completion	comp_ready;
 	struct completion	comp_cmd_done;
@@ -2248,6 +2251,7 @@ static int atmel_nand_nfc_probe(struct platform_device *pdev)
 {
 	struct atmel_nfc *nfc = &nand_nfc;
 	struct resource *nfc_cmd_regs, *nfc_hsmc_regs, *nfc_sram;
+	int ret;
 
 	nfc_cmd_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	nfc->base_cmd_regs = devm_ioremap_resource(&pdev->dev, nfc_cmd_regs);
@@ -2279,8 +2283,28 @@ static int atmel_nand_nfc_probe(struct platform_device *pdev)
 	nfc_writel(nfc->hsmc_regs, IDR, 0xffffffff);
 	nfc_readl(nfc->hsmc_regs, SR);	/* clear the NFC_SR */
 
+	nfc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(nfc->clk)) {
+		ret = clk_prepare_enable(nfc->clk);
+		if (ret)
+			return ret;
+	} else {
+		dev_warn(&pdev->dev, "NFC clock missing, update your Device Tree");
+	}
+
 	nfc->is_initialized = true;
 	dev_info(&pdev->dev, "NFC is probed.\n");
+
+	return 0;
+}
+
+static int atmel_nand_nfc_remove(struct platform_device *pdev)
+{
+	struct atmel_nfc *nfc = &nand_nfc;
+
+	if (!IS_ERR(nfc->clk))
+		clk_disable_unprepare(nfc->clk);
+
 	return 0;
 }
 
@@ -2297,6 +2321,7 @@ static struct platform_driver atmel_nand_nfc_driver = {
 		.of_match_table = of_match_ptr(atmel_nand_nfc_match),
 	},
 	.probe = atmel_nand_nfc_probe,
+	.remove = atmel_nand_nfc_remove,
 };
 
 static struct platform_driver atmel_nand_driver = {