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@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
index c4728839d0c1333098b38fe4e7aa96e3e0ab7f9e..6edc3b616e98c6a9f7547be9c5393fbda56f1206 100644 (file)
--- 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@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 9c5f717bda548a9019fedc599d4e7f6db6e8a581..d1e502f8dbd0b647b6506c66d45887d7a493b09c 100644 (file)
--- 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 = {