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path: root/drivers/w1/masters/mxc_w1.c
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Diffstat (limited to 'drivers/w1/masters/mxc_w1.c')
-rw-r--r--drivers/w1/masters/mxc_w1.c31
1 files changed, 22 insertions, 9 deletions
diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
index 15c7251b0556..1e5d94c5afc9 100644
--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -46,7 +46,6 @@
struct mxc_w1_device {
void __iomem *regs;
- unsigned int clkdiv;
struct clk *clk;
struct w1_bus_master bus_master;
};
@@ -106,8 +105,10 @@ static u8 mxc_w1_ds2_touch_bit(void *data, u8 bit)
static int mxc_w1_probe(struct platform_device *pdev)
{
struct mxc_w1_device *mdev;
+ unsigned long clkrate;
struct resource *res;
- int err = 0;
+ unsigned int clkdiv;
+ int err;
mdev = devm_kzalloc(&pdev->dev, sizeof(struct mxc_w1_device),
GFP_KERNEL);
@@ -118,27 +119,39 @@ static int mxc_w1_probe(struct platform_device *pdev)
if (IS_ERR(mdev->clk))
return PTR_ERR(mdev->clk);
- mdev->clkdiv = (clk_get_rate(mdev->clk) / 1000000) - 1;
+ clkrate = clk_get_rate(mdev->clk);
+ if (clkrate < 10000000)
+ dev_warn(&pdev->dev,
+ "Low clock frequency causes improper function\n");
+
+ clkdiv = DIV_ROUND_CLOSEST(clkrate, 1000000);
+ clkrate /= clkdiv;
+ if ((clkrate < 980000) || (clkrate > 1020000))
+ dev_warn(&pdev->dev,
+ "Incorrect time base frequency %lu Hz\n", clkrate);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mdev->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(mdev->regs))
return PTR_ERR(mdev->regs);
- clk_prepare_enable(mdev->clk);
- __raw_writeb(mdev->clkdiv, mdev->regs + MXC_W1_TIME_DIVIDER);
+ err = clk_prepare_enable(mdev->clk);
+ if (err)
+ return err;
+
+ __raw_writeb(clkdiv - 1, mdev->regs + MXC_W1_TIME_DIVIDER);
mdev->bus_master.data = mdev;
mdev->bus_master.reset_bus = mxc_w1_ds2_reset_bus;
mdev->bus_master.touch_bit = mxc_w1_ds2_touch_bit;
- err = w1_add_master_device(&mdev->bus_master);
+ platform_set_drvdata(pdev, mdev);
+ err = w1_add_master_device(&mdev->bus_master);
if (err)
- return err;
+ clk_disable_unprepare(mdev->clk);
- platform_set_drvdata(pdev, mdev);
- return 0;
+ return err;
}
/*