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

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>

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index d557279446ed48970fbe0e91e8cac13a8b8de99d..34f3031d5c40628447e469c1db30da8e200d3b20 100644 (file)
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -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,