[PATCH 4/5] pwm: rockchip: Add atomic updated feature for rk3328

[David Wu]

The rk3328 soc supports atomic update, we could lock the configuration
of period and duty at first, after unlock is configured, the period and
duty are effective at the same time.

If the polarity, period and duty need to be configured together,
the way for atomic update is "configure lock and old polarity" ->
"configure period and duty" -> "configure unlock and new polarity".

Signed-off-by: David Wu <david.wu@xxxxxxxxxxxxxx>
---
 .../devicetree/bindings/pwm/pwm-rockchip.txt       |  1 +
 drivers/pwm/pwm-rockchip.c                         | 50 +++++++++++++++++++---
 2 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/pwm/pwm-rockchip.txt b/Documentation/devicetree/bindings/pwm/pwm-rockchip.txt
index 2350ef9..152c736 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-rockchip.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm-rockchip.txt
@@ -4,6 +4,7 @@ Required properties:
  - compatible: should be "rockchip,<name>-pwm"
    "rockchip,rk2928-pwm": found on RK29XX,RK3066 and RK3188 SoCs
    "rockchip,rk3288-pwm": found on RK3288 SoC
+   "rockchip,rk3328-pwm": found on RK3328 SoC
    "rockchip,vop-pwm": found integrated in VOP on RK3288 SoC
  - reg: physical base address and length of the controller's registers
  - clocks: See ../clock/clock-bindings.txt
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index eb630ff..d8801ae8 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -29,6 +29,7 @@
 #define PWM_INACTIVE_POSITIVE	(1 << 4)
 #define PWM_POLARITY_MASK	(PWM_DUTY_POSITIVE | PWM_INACTIVE_POSITIVE)
 #define PWM_OUTPUT_LEFT		(0 << 5)
+#define PWM_LOCK_EN		(1 << 6)
 #define PWM_LP_DISABLE		(0 << 8)
 
 struct rockchip_pwm_chip {
@@ -50,6 +51,7 @@ struct rockchip_pwm_data {
 	struct rockchip_pwm_regs regs;
 	unsigned int prescaler;
 	bool supports_polarity;
+	bool supports_atomic_update;
 	const struct pwm_ops *ops;
 
 	void (*set_enable)(struct pwm_chip *chip,
@@ -201,6 +203,14 @@ static void rockchip_pwm_config_v2(struct pwm_chip *chip,
 	clk_rate = clk_get_rate(pc->clk);
 
 	/*
+	 * Lock the period and duty of previous configuration, then
+	 * change the duty and period, that would not be effective.
+	 */
+	ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
+	ctrl |= PWM_LOCK_EN;
+	writel_relaxed(ctrl, pc->base + pc->data->regs.ctrl);
+
+	/*
 	 * Since period and duty cycle registers have a width of 32
 	 * bits, every possible input period can be obtained using the
 	 * default prescaler value for all practical clock rate values.
@@ -222,6 +232,12 @@ static void rockchip_pwm_config_v2(struct pwm_chip *chip,
 	else
 		ctrl |= PWM_DUTY_POSITIVE | PWM_INACTIVE_NEGATIVE;
 
+	/*
+	 * Unlock and set polarity at the same time,
+	 * the configuration of duty, period and polarity
+	 * would be effective together at next period.
+	 */
+	ctrl &= ~PWM_LOCK_EN;
 	writel(ctrl, pc->base + pc->data->regs.ctrl);
 }
 
@@ -261,11 +277,18 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	if (ret)
 		return ret;
 
-	if (state->polarity != curstate.polarity && enabled) {
-		ret = rockchip_pwm_enable(chip, pwm, false);
-		if (ret)
-			goto out;
-		enabled = false;
+	/*
+	 * If the atomic update is supported, then go to the pwm config,
+	 * no need to do this, it could ensure the atomic update for polarity
+	 * changed.
+	 */
+	if (pc->data->supports_atomic_update) {
+		if (state->polarity != curstate.polarity && enabled) {
+			ret = rockchip_pwm_enable(chip, pwm, false);
+			if (ret)
+				goto out;
+			enabled = false;
+		}
 	}
 
 	pc->data->pwm_config(chip, pwm, state->duty_cycle,
@@ -345,9 +368,26 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	.pwm_config = rockchip_pwm_config_v2,
 };
 
+static const struct rockchip_pwm_data pwm_data_v3 = {
+	.regs = {
+		.duty = 0x08,
+		.period = 0x04,
+		.cntr = 0x00,
+		.ctrl = 0x0c,
+	},
+	.prescaler = 1,
+	.supports_polarity = true,
+	.supports_atomic_update = true,
+	.ops = &rockchip_pwm_ops_v2,
+	.set_enable = rockchip_pwm_set_enable_v2,
+	.get_state = rockchip_pwm_get_state_v2,
+	.pwm_config = rockchip_pwm_config_v2,
+};
+
 static const struct of_device_id rockchip_pwm_dt_ids[] = {
 	{ .compatible = "rockchip,rk2928-pwm", .data = &pwm_data_v1},
 	{ .compatible = "rockchip,rk3288-pwm", .data = &pwm_data_v2},
+	{ .compatible = "rockchip,rk3328-pwm", .data = &pwm_data_v3},
 	{ .compatible = "rockchip,vop-pwm", .data = &pwm_data_vop},
 	{ /* sentinel */ }
 };
-- 
1.9.1