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Commit 0ca1a11a authored by Lukasz Majewski's avatar Lukasz Majewski Committed by Thierry Reding
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pwm: imx: Provide atomic PWM support for i.MX PWMv2 



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

Suggested-by: default avatarStefan Agner <stefan@agner.ch>
Suggested-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarLukasz Majewski <l.majewski@majess.pl>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 73b1ff1f

drivers/pwm/pwm-imx.c

+67 −0
Original line number Diff line number Diff line
@@ -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,