watchdog: MIPS: lantiq: implement OF support and minor fixes

Add support for OF. We also apply the following small fixes
* reduce boiler plate by using devm_request_and_ioremap
* sane error path for the clock
* move LTQ_RST_CAUSE_WDTRST to a soc specific header file
* add a message to show that the driver loaded

Signed-off-by: John Crispin <blogic@openwrt.org>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3810/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 25 insertions, 31 deletions

diff --git a/drivers/watchdog/lantiq_wdt.c b/drivers/watchdog/lantiq_wdt.c
index a9593a3a32a0..2e74c3a8ee58 100644
--- a/drivers/watchdog/lantiq_wdt.c
+++ b/drivers/watchdog/lantiq_wdt.c
@@ -13,14 +13,15 @@
 #include <linux/fs.h>
 #include <linux/miscdevice.h>
 #include <linux/watchdog.h>
-#include <linux/platform_device.h>
+#include <linux/of_platform.h>
 #include <linux/uaccess.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 
-#include <lantiq.h>
+#include <lantiq_soc.h>
 
-/* Section 3.4 of the datasheet
+/*
+ * Section 3.4 of the datasheet
  * The password sequence protects the WDT control register from unintended
  * write actions, which might cause malfunction of the WDT.
  *
@@ -70,7 +71,8 @@ ltq_wdt_disable(void)
 {
         /* write the first password magic */
         ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
-        /* write the second password magic with no config
+        /*
+         * write the second password magic with no config
          * this turns the watchdog off
          */
         ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
@@ -184,7 +186,7 @@ static struct miscdevice ltq_wdt_miscdev = {
         .fops   = &ltq_wdt_fops,
 };
 
-static int __init
+static int __devinit
 ltq_wdt_probe(struct platform_device *pdev)
 {
         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -194,28 +196,27 @@ ltq_wdt_probe(struct platform_device *pdev)
                 dev_err(&pdev->dev, "cannot obtain I/O memory region");
                 return -ENOENT;
         }
-        res = devm_request_mem_region(&pdev->dev, res->start,
-                resource_size(res), dev_name(&pdev->dev));
-        if (!res) {
-                dev_err(&pdev->dev, "cannot request I/O memory region");
-                return -EBUSY;
-        }
-        ltq_wdt_membase = devm_ioremap_nocache(&pdev->dev, res->start,
-                resource_size(res));
+
+        ltq_wdt_membase = devm_request_and_ioremap(&pdev->dev, res);
         if (!ltq_wdt_membase) {
                 dev_err(&pdev->dev, "cannot remap I/O memory region\n");
                 return -ENOMEM;
         }
 
         /* we do not need to enable the clock as it is always running */
-        clk = clk_get(&pdev->dev, "io");
-        WARN_ON(!clk);
+        clk = clk_get_io();
+        if (IS_ERR(clk)) {
+                dev_err(&pdev->dev, "Failed to get clock\n");
+                return -ENOENT;
+        }
         ltq_io_region_clk_rate = clk_get_rate(clk);
         clk_put(clk);
 
+        /* find out if the watchdog caused the last reboot */
         if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
                 ltq_wdt_bootstatus = WDIOF_CARDRESET;
 
+        dev_info(&pdev->dev, "Init done\n");
         return misc_register(&ltq_wdt_miscdev);
 }
 
@@ -227,33 +228,26 @@ ltq_wdt_remove(struct platform_device *pdev)
         return 0;
 }
 
+static const struct of_device_id ltq_wdt_match[] = {
+        { .compatible = "lantiq,wdt" },
+        {},
+};
+MODULE_DEVICE_TABLE(of, ltq_wdt_match);
 
 static struct platform_driver ltq_wdt_driver = {
+        .probe = ltq_wdt_probe,
         .remove = __devexit_p(ltq_wdt_remove),
         .driver = {
-                .name = "ltq_wdt",
+                .name = "wdt",
                 .owner = THIS_MODULE,
+                .of_match_table = ltq_wdt_match,
         },
 };
 
-static int __init
-init_ltq_wdt(void)
-{
-        return platform_driver_probe(&ltq_wdt_driver, ltq_wdt_probe);
-}
-
-static void __exit
-exit_ltq_wdt(void)
-{
-        return platform_driver_unregister(&ltq_wdt_driver);
-}
-
-module_init(init_ltq_wdt);
-module_exit(exit_ltq_wdt);
+module_platform_driver(ltq_wdt_driver);
 
 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
-
 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
 MODULE_DESCRIPTION("Lantiq SoC Watchdog");
 MODULE_LICENSE("GPL");