pwm: rockchip: Add support for hardware readout

Implement the ->get_state() function to expose initial state.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 67 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index 68d72ce8fba5..c72b4192c7bf 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -51,6 +51,8 @@ struct rockchip_pwm_data {
 
         void (*set_enable)(struct pwm_chip *chip,
                            struct pwm_device *pwm, bool enable);
+        void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
+                          struct pwm_state *state);
 };
 
 static inline struct rockchip_pwm_chip *to_rockchip_pwm_chip(struct pwm_chip *c)
@@ -75,6 +77,19 @@ static void rockchip_pwm_set_enable_v1(struct pwm_chip *chip,
         writel_relaxed(val, pc->base + pc->data->regs.ctrl);
 }
 
+static void rockchip_pwm_get_state_v1(struct pwm_chip *chip,
+                                      struct pwm_device *pwm,
+                                      struct pwm_state *state)
+{
+        struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+        u32 enable_conf = PWM_CTRL_OUTPUT_EN | PWM_CTRL_TIMER_EN;
+        u32 val;
+
+        val = readl_relaxed(pc->base + pc->data->regs.ctrl);
+        if ((val & enable_conf) == enable_conf)
+                state->enabled = true;
+}
+
 static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
                                        struct pwm_device *pwm, bool enable)
 {
@@ -98,6 +113,53 @@ static void rockchip_pwm_set_enable_v2(struct pwm_chip *chip,
         writel_relaxed(val, pc->base + pc->data->regs.ctrl);
 }
 
+static void rockchip_pwm_get_state_v2(struct pwm_chip *chip,
+                                      struct pwm_device *pwm,
+                                      struct pwm_state *state)
+{
+        struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+        u32 enable_conf = PWM_OUTPUT_LEFT | PWM_LP_DISABLE | PWM_ENABLE |
+                          PWM_CONTINUOUS;
+        u32 val;
+
+        val = readl_relaxed(pc->base + pc->data->regs.ctrl);
+        if ((val & enable_conf) != enable_conf)
+                return;
+
+        state->enabled = true;
+
+        if (!(val & PWM_DUTY_POSITIVE))
+                state->polarity = PWM_POLARITY_INVERSED;
+}
+
+static void rockchip_pwm_get_state(struct pwm_chip *chip,
+                                   struct pwm_device *pwm,
+                                   struct pwm_state *state)
+{
+        struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
+        unsigned long clk_rate;
+        u64 tmp;
+        int ret;
+
+        ret = clk_enable(pc->clk);
+        if (ret)
+                return;
+
+        clk_rate = clk_get_rate(pc->clk);
+
+        tmp = readl_relaxed(pc->base + pc->data->regs.period);
+        tmp *= pc->data->prescaler * NSEC_PER_SEC;
+        state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+        tmp = readl_relaxed(pc->base + pc->data->regs.duty);
+        tmp *= pc->data->prescaler * NSEC_PER_SEC;
+        state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+        pc->data->get_state(chip, pwm, state);
+
+        clk_disable(pc->clk);
+}
+
 static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
                                int duty_ns, int period_ns)
 {
@@ -170,6 +232,7 @@ static void rockchip_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 }
 
 static const struct pwm_ops rockchip_pwm_ops_v1 = {
+        .get_state = rockchip_pwm_get_state,
         .config = rockchip_pwm_config,
         .enable = rockchip_pwm_enable,
         .disable = rockchip_pwm_disable,
@@ -177,6 +240,7 @@ static const struct pwm_ops rockchip_pwm_ops_v1 = {
 };
 
 static const struct pwm_ops rockchip_pwm_ops_v2 = {
+        .get_state = rockchip_pwm_get_state,
         .config = rockchip_pwm_config,
         .set_polarity = rockchip_pwm_set_polarity,
         .enable = rockchip_pwm_enable,
@@ -194,6 +258,7 @@ static const struct rockchip_pwm_data pwm_data_v1 = {
         .prescaler = 2,
         .ops = &rockchip_pwm_ops_v1,
         .set_enable = rockchip_pwm_set_enable_v1,
+        .get_state = rockchip_pwm_get_state_v1,
 };
 
 static const struct rockchip_pwm_data pwm_data_v2 = {
@@ -206,6 +271,7 @@ static const struct rockchip_pwm_data pwm_data_v2 = {
         .prescaler = 1,
         .ops = &rockchip_pwm_ops_v2,
         .set_enable = rockchip_pwm_set_enable_v2,
+        .get_state = rockchip_pwm_get_state_v2,
 };
 
 static const struct rockchip_pwm_data pwm_data_vop = {
@@ -218,6 +284,7 @@ static const struct rockchip_pwm_data pwm_data_vop = {
         .prescaler = 1,
         .ops = &rockchip_pwm_ops_v2,
         .set_enable = rockchip_pwm_set_enable_v2,
+        .get_state = rockchip_pwm_get_state_v2,
 };
 
 static const struct of_device_id rockchip_pwm_dt_ids[] = {