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authorLars-Peter Clausen <lars@metafoo.de>2010-04-13 20:52:41 +0000
committerLars-Peter Clausen <lars@metafoo.de>2010-04-13 20:52:41 +0000
commite438c665db5e53b8a6f8f0eb4c7dcb6c735e2c78 (patch)
tree77a70f7c2b68d7169ad1a8cf3b9d5161a1f54f34 /target/linux/mx2/patches-2.6.34
parent498bf7402a18ea77138aebc41e808cc1b1b3b4c8 (diff)
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vp6500: Add backlight device
SVN-Revision: 20843
Diffstat (limited to 'target/linux/mx2/patches-2.6.34')
-rw-r--r--target/linux/mx2/patches-2.6.34/040-pwm.patch137
1 files changed, 137 insertions, 0 deletions
diff --git a/target/linux/mx2/patches-2.6.34/040-pwm.patch b/target/linux/mx2/patches-2.6.34/040-pwm.patch
new file mode 100644
index 0000000000..55e846ec17
--- /dev/null
+++ b/target/linux/mx2/patches-2.6.34/040-pwm.patch
@@ -0,0 +1,137 @@
+diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c
+index c36f263..acc5dc1 100644
+--- a/arch/arm/plat-mxc/pwm.c
++++ b/arch/arm/plat-mxc/pwm.c
+@@ -25,6 +25,11 @@
+ #define MX1_PWMS 0x04 /* PWM Sample Register */
+ #define MX1_PWMP 0x08 /* PWM Period Register */
+
++#define MX1_PWMC_EN (1 << 4)
++#define MX1_PWMC_PRESCALER_MASK (0x7f << 8)
++#define MX1_PWMC_PRESCALER(x) ((x & 0x7f) << 8)
++#define MX1_PWMC_CLKSEL_MASK 0x3
++#define MX1_PWMC_CLKSEL(x) ((x & 0x3))
+
+ /* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
+
+@@ -54,25 +59,32 @@ struct pwm_device {
+
+ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+ {
++ unsigned long long c;
++ unsigned long period_cycles, duty_cycles, prescale;
++
+ if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+ return -EINVAL;
+
+- if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
+- unsigned long long c;
+- unsigned long period_cycles, duty_cycles, prescale;
+- u32 cr;
++ c = clk_get_rate(pwm->clk);
++
++ c = c * period_ns;
++
++ if (cpu_is_mx1() || cpu_is_mx2())
++ c >>= 1;
+
+- c = clk_get_rate(pwm->clk);
+- c = c * period_ns;
+- do_div(c, 1000000000);
+- period_cycles = c;
++ do_div(c, 1000000000);
++ period_cycles = c;
+
+- prescale = period_cycles / 0x10000 + 1;
++ prescale = period_cycles / 0x10000 + 1;
+
+- period_cycles /= prescale;
+- c = (unsigned long long)period_cycles * duty_ns;
+- do_div(c, period_ns);
+- duty_cycles = c;
++ period_cycles /= prescale;
++ c = (unsigned long long)period_cycles * duty_ns;
++ do_div(c, period_ns);
++ duty_cycles = c;
++
++
++ if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
++ u32 cr;
+
+ writel(duty_cycles, pwm->mmio_base + MX3_PWMSAR);
+ writel(period_cycles, pwm->mmio_base + MX3_PWMPR);
+@@ -86,25 +98,28 @@ int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+
+ writel(cr, pwm->mmio_base + MX3_PWMCR);
+ } else if (cpu_is_mx1() || cpu_is_mx21()) {
+- /* The PWM subsystem allows for exact frequencies. However,
+- * I cannot connect a scope on my device to the PWM line and
+- * thus cannot provide the program the PWM controller
+- * exactly. Instead, I'm relying on the fact that the
+- * Bootloader (u-boot or WinCE+haret) has programmed the PWM
+- * function group already. So I'll just modify the PWM sample
+- * register to follow the ratio of duty_ns vs. period_ns
+- * accordingly.
+- *
+- * This is good enough for programming the brightness of
+- * the LCD backlight.
+- *
+- * The real implementation would divide PERCLK[0] first by
+- * both the prescaler (/1 .. /128) and then by CLKSEL
+- * (/2 .. /16).
+- */
+- u32 max = readl(pwm->mmio_base + MX1_PWMP);
+- u32 p = max * duty_ns / period_ns;
+- writel(max - p, pwm->mmio_base + MX1_PWMS);
++ unsigned long clksel = 0;
++ u32 ctrl;
++
++ while (prescale >= 0x80 && clksel < 4) {
++ prescale >>= 1;
++ ++clksel;
++ }
++
++ if (clksel > 3)
++ return -EINVAL;
++
++ ctrl = readl(pwm->mmio_base + MX1_PWMC);
++ writel(ctrl & ~MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
++
++ writel(duty_cycles, pwm->mmio_base + MX1_PWMS);
++ writel(period_cycles, pwm->mmio_base + MX1_PWMP);
++
++ ctrl &= ~(MX1_PWMC_PRESCALER_MASK | MX1_PWMC_CLKSEL_MASK);
++ ctrl |= MX1_PWMC_PRESCALER(prescale);
++ ctrl |= MX1_PWMC_CLKSEL(clksel);
++ writel(ctrl, pwm->mmio_base + MX1_PWMC);
++
+ } else {
+ BUG();
+ }
+@@ -116,6 +130,11 @@ EXPORT_SYMBOL(pwm_config);
+ int pwm_enable(struct pwm_device *pwm)
+ {
+ int rc = 0;
++ if (cpu_is_mx1() || cpu_is_mx2()) {
++ u32 ctrl;
++ ctrl = readl(pwm->mmio_base + MX1_PWMC);
++ writel(ctrl | MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
++ }
+
+ if (!pwm->clk_enabled) {
+ rc = clk_enable(pwm->clk);
+@@ -128,7 +147,13 @@ EXPORT_SYMBOL(pwm_enable);
+
+ void pwm_disable(struct pwm_device *pwm)
+ {
+- writel(0, pwm->mmio_base + MX3_PWMCR);
++ if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25()) {
++ writel(0, pwm->mmio_base + MX3_PWMCR);
++ } else if (cpu_is_mx1() || cpu_is_mx2()) {
++ u32 ctrl;
++ ctrl = readl(pwm->mmio_base + MX1_PWMC);
++ writel(ctrl & ~MX1_PWMC_EN, pwm->mmio_base + MX1_PWMC);
++ }
+
+ if (pwm->clk_enabled) {
+ clk_disable(pwm->clk);