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Subject[PATCH 1/6] unicore32: pwm: Properly remap memory-mapped registers
Date
Instead of writing to the timer controller registers by dereferencing a
pointer to the memory location, properly remap the memory region with a
call to ioremap_nocache() and access the registers using writel().

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
---
arch/unicore32/kernel/pwm.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/arch/unicore32/kernel/pwm.c b/arch/unicore32/kernel/pwm.c
index 4615d51..410b786 100644
--- a/arch/unicore32/kernel/pwm.c
+++ b/arch/unicore32/kernel/pwm.c
@@ -23,10 +23,16 @@
#include <asm/div64.h>
#include <mach/hardware.h>

+#define PWCR 0x00
+#define DCCR 0x04
+#define PCR 0x08
+
struct pwm_device {
struct list_head node;
struct platform_device *pdev;

+ void __iomem *base;
+
const char *label;
struct clk *clk;
int clk_enabled;
@@ -69,9 +75,11 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
* before writing to the registers
*/
clk_enable(pwm->clk);
- OST_PWMPWCR = prescale;
- OST_PWMDCCR = pv - dc;
- OST_PWMPCR = pv;
+
+ writel(prescale, pwm->base + PWCR);
+ writel(pv - dc, pwm->base + DCCR);
+ writel(pv, pwm->base + PCR);
+
clk_disable(pwm->clk);

return 0;
@@ -190,10 +198,19 @@ static struct pwm_device *pwm_probe(struct platform_device *pdev,
goto err_free_clk;
}

+ pwm->base = ioremap_nocache(r->start, resource_size(r));
+ if (pwm->base == NULL) {
+ dev_err(&pdev->dev, "failed to remap memory resource\n");
+ ret = -EADDRNOTAVAIL;
+ goto err_release_mem;
+ }
+
__add_pwm(pwm);
platform_set_drvdata(pdev, pwm);
return pwm;

+err_release_mem:
+ release_mem_region(r->start, resource_size(r));
err_free_clk:
clk_put(pwm->clk);
err_free:
@@ -224,6 +241,8 @@ static int __devexit pwm_remove(struct platform_device *pdev)
list_del(&pwm->node);
mutex_unlock(&pwm_lock);

+ iounmap(pwm->base);
+
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
release_mem_region(r->start, resource_size(r));

--
1.7.12


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