staging: dgnc: remove explicit cast

[karo-tx-linux.git] / drivers / rtc / rtc-m48t86.c

diff --git a/drivers/rtc/rtc-m48t86.c b/drivers/rtc/rtc-m48t86.c
index 4dc4af41c03d66d715762a45746dff4ff774f791..02af045305dd3ce156a7f60b14cc153e548ce60c 100644 (file)
--- a/drivers/rtc/rtc-m48t86.c
+++ b/drivers/rtc/rtc-m48t86.c
@@ -16,7 +16,6 @@
 #include <linux/module.h>
 #include <linux/rtc.h>
 #include <linux/platform_device.h>
-#include <linux/platform_data/rtc-m48t86.h>
 #include <linux/bcd.h>
 #include <linux/io.h>
 
@@ -45,7 +44,6 @@ struct m48t86_rtc_info {
        void __iomem *index_reg;
        void __iomem *data_reg;
        struct rtc_device *rtc;
-       struct m48t86_ops *ops;
 };
 
 static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
@@ -53,12 +51,9 @@ static unsigned char m48t86_readb(struct device *dev, unsigned long addr)
        struct m48t86_rtc_info *info = dev_get_drvdata(dev);
        unsigned char value;
 
-       if (info->ops) {
-               value = info->ops->readbyte(addr);
-       } else {
-               writeb(addr, info->index_reg);
-               value = readb(info->data_reg);
-       }
+       writeb(addr, info->index_reg);
+       value = readb(info->data_reg);
+
        return value;
 }
 
@@ -67,12 +62,8 @@ static void m48t86_writeb(struct device *dev,
 {
        struct m48t86_rtc_info *info = dev_get_drvdata(dev);
 
-       if (info->ops) {
-               info->ops->writebyte(value, addr);
-       } else {
-               writeb(addr, info->index_reg);
-               writeb(value, info->data_reg);
-       }
+       writeb(addr, info->index_reg);
+       writeb(value, info->data_reg);
 }
 
 static int m48t86_rtc_read_time(struct device *dev, struct rtc_time *tm)
@@ -201,36 +192,68 @@ static ssize_t m48t86_nvram_write(struct file *filp, struct kobject *kobj,
 static BIN_ATTR(nvram, 0644, m48t86_nvram_read, m48t86_nvram_write,
                M48T86_NVRAM_LEN);
 
+/*
+ * The RTC is an optional feature at purchase time on some Technologic Systems
+ * boards. Verify that it actually exists by checking if the last two bytes
+ * of the NVRAM can be changed.
+ *
+ * This is based on the method used in their rtc7800.c example.
+ */
+static bool m48t86_verify_chip(struct platform_device *pdev)
+{
+       unsigned int offset0 = M48T86_NVRAM(M48T86_NVRAM_LEN - 2);
+       unsigned int offset1 = M48T86_NVRAM(M48T86_NVRAM_LEN - 1);
+       unsigned char tmp0, tmp1;
+
+       tmp0 = m48t86_readb(&pdev->dev, offset0);
+       tmp1 = m48t86_readb(&pdev->dev, offset1);
+
+       m48t86_writeb(&pdev->dev, 0x00, offset0);
+       m48t86_writeb(&pdev->dev, 0x55, offset1);
+       if (m48t86_readb(&pdev->dev, offset1) == 0x55) {
+               m48t86_writeb(&pdev->dev, 0xaa, offset1);
+               if (m48t86_readb(&pdev->dev, offset1) == 0xaa &&
+                   m48t86_readb(&pdev->dev, offset0) == 0x00) {
+                       m48t86_writeb(&pdev->dev, tmp0, offset0);
+                       m48t86_writeb(&pdev->dev, tmp1, offset1);
+
+                       return true;
+               }
+       }
+       return false;
+}
+
 static int m48t86_rtc_probe(struct platform_device *pdev)
 {
        struct m48t86_rtc_info *info;
+       struct resource *res;
        unsigned char reg;
 
        info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
        if (!info)
                return -ENOMEM;
 
-       info->ops = dev_get_platdata(&pdev->dev);
-       if (!info->ops) {
-               struct resource *res;
-
-               res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-               if (!res)
-                       return -ENODEV;
-               info->index_reg = devm_ioremap_resource(&pdev->dev, res);
-               if (IS_ERR(info->index_reg))
-                       return PTR_ERR(info->index_reg);
-
-               res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-               if (!res)
-                       return -ENODEV;
-               info->data_reg = devm_ioremap_resource(&pdev->dev, res);
-               if (IS_ERR(info->data_reg))
-                       return PTR_ERR(info->data_reg);
-       }
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -ENODEV;
+       info->index_reg = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(info->index_reg))
+               return PTR_ERR(info->index_reg);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+       if (!res)
+               return -ENODEV;
+       info->data_reg = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(info->data_reg))
+               return PTR_ERR(info->data_reg);
 
        dev_set_drvdata(&pdev->dev, info);
 
+       if (!m48t86_verify_chip(pdev)) {
+               dev_info(&pdev->dev, "RTC not present\n");
+               return -ENODEV;
+       }
+
        info->rtc = devm_rtc_device_register(&pdev->dev, "m48t86",
                                             &m48t86_rtc_ops, THIS_MODULE);
        if (IS_ERR(info->rtc))