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pwm: imx: Provide atomic PWM support for i.MX PWMv2

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This commit provides apply() callback implementation for i.MX's PWMv2.

Suggested-by: Stefan Agner <stefan@agner.ch>
Suggested-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Lukasz Majewski 2017-01-29 22:54:11 +01:00 committed by Thierry Reding
parent 73b1ff1f3e
commit 0ca1a11a1d
1 changed files with 67 additions and 0 deletions
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67
drivers/pwm/pwm-imx.c
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@ -248,6 +248,72 @@ static int imx_pwm_config(struct pwm_chip *chip,
return ret;
}
static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
unsigned long period_cycles, duty_cycles, prescale;
struct imx_chip *imx = to_imx_chip(chip);
struct pwm_state cstate;
unsigned long long c;
int ret;
pwm_get_state(pwm, &cstate);
if (state->enabled) {
c = clk_get_rate(imx->clk_per);
c *= state->period;
do_div(c, 1000000000);
period_cycles = c;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
c = (unsigned long long)period_cycles * state->duty_cycle;
do_div(c, state->period);
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;
/*
* Wait for a free FIFO slot if the PWM is already enabled, and
* flush the FIFO if the PWM was disabled and is about to be
* enabled.
*/
if (cstate.enabled) {
imx_pwm_wait_fifo_slot(chip, pwm);
} else {
ret = clk_prepare_enable(imx->clk_per);
if (ret)
return ret;
imx_pwm_sw_reset(chip);
}
writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
writel(period_cycles, imx->mmio_base + MX3_PWMPR);
writel(MX3_PWMCR_PRESCALER(prescale) |
MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH |
MX3_PWMCR_EN,
imx->mmio_base + MX3_PWMCR);
} else if (cstate.enabled) {
writel(0, imx->mmio_base + MX3_PWMCR);
clk_disable_unprepare(imx->clk_per);
}
return 0;
}
static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);
@ -279,6 +345,7 @@ static const struct pwm_ops imx_pwm_ops_v1 = {
};
static const struct pwm_ops imx_pwm_ops_v2 = {
.apply = imx_pwm_apply_v2,
.enable = imx_pwm_enable,
.disable = imx_pwm_disable,
.config = imx_pwm_config,