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pwm: i.MX: factor out SoC specific functions

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To cleanup the code and to make it easier to support different
SoCs.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit is contained in:
Sascha Hauer 2012-07-03 17:28:14 +02:00 committed by Thierry Reding
parent daa5629b21
commit 19e7333323
1 changed files with 84 additions and 64 deletions
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148
drivers/pwm/pwm-imx.c
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@ -46,79 +46,94 @@ struct imx_chip {
void __iomem *mmio_base;
struct pwm_chip chip;
int (*config)(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns);
};
#define to_imx_chip(chip) container_of(chip, struct imx_chip, chip)
static int imx_pwm_config_v1(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
/*
* 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(imx->mmio_base + MX1_PWMP);
u32 p = max * duty_ns / period_ns;
writel(max - p, imx->mmio_base + MX1_PWMS);
return 0;
}
static int imx_pwm_config_v2(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
u32 cr;
c = clk_get_rate(imx->clk);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
c = (unsigned long long)period_cycles * duty_ns;
do_div(c, period_ns);
duty_cycles = c;
/*
* according to imx pwm RM, the real period value should be
* PERIOD value in PWMPR plus 2.
*/
if (period_cycles > 2)
period_cycles -= 2;
else
period_cycles = 0;
writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
writel(period_cycles, imx->mmio_base + MX3_PWMPR);
cr = MX3_PWMCR_PRESCALER(prescale) |
MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
if (cpu_is_mx25())
cr |= MX3_PWMCR_CLKSRC_IPG;
else
cr |= MX3_PWMCR_CLKSRC_IPG_HIGH;
writel(cr, imx->mmio_base + MX3_PWMCR);
return 0;
}
static int imx_pwm_config(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
struct imx_chip *imx = to_imx_chip(chip);
if (!(cpu_is_mx1() || cpu_is_mx21())) {
unsigned long long c;
unsigned long period_cycles, duty_cycles, prescale;
u32 cr;
c = clk_get_rate(imx->clk);
c = c * period_ns;
do_div(c, 1000000000);
period_cycles = c;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
c = (unsigned long long)period_cycles * duty_ns;
do_div(c, period_ns);
duty_cycles = c;
/*
* according to imx pwm RM, the real period value should be
* PERIOD value in PWMPR plus 2.
*/
if (period_cycles > 2)
period_cycles -= 2;
else
period_cycles = 0;
writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
writel(period_cycles, imx->mmio_base + MX3_PWMPR);
cr = MX3_PWMCR_PRESCALER(prescale) |
MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
if (cpu_is_mx25())
cr |= MX3_PWMCR_CLKSRC_IPG;
else
cr |= MX3_PWMCR_CLKSRC_IPG_HIGH;
writel(cr, imx->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(imx->mmio_base + MX1_PWMP);
u32 p = max * duty_ns / period_ns;
writel(max - p, imx->mmio_base + MX1_PWMS);
} else {
BUG();
}
return 0;
return imx->config(chip, pwm, duty_ns, period_ns);
}
static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
@ -187,6 +202,11 @@ static int __devinit imx_pwm_probe(struct platform_device *pdev)
if (imx->mmio_base == NULL)
return -EADDRNOTAVAIL;
if (cpu_is_mx1() || cpu_is_mx21())
imx->config = imx_pwm_config_v1;
else
imx->config = imx_pwm_config_v2;
ret = pwmchip_add(&imx->chip);
if (ret < 0)
return ret;