vp6500: Add backlight device

SVN-Revision: 20843

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);