pwm: tegra: add probe function

When PWM config was updated the clock was restarted which caused loss of
previous configuration of other channels. Further this fixes a bug/hang
that can happen when set_enable was called before set_config.

Signed-off-by: Jonas Schwöbel <jonasschwoebel@yahoo.de>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

diff --git a/drivers/pwm/tegra_pwm.c b/drivers/pwm/tegra_pwm.c
index e3f1417f2ad050f295d20743ce134fb0de4822c6..919728b821fa690bbcdc5a662e755c855cad42ca 100644 (file)
--- a/drivers/pwm/tegra_pwm.c
+++ b/drivers/pwm/tegra_pwm.c
@@ -4,6 +4,7 @@
  */
 
 #include <dm.h>
+#include <clk.h>
 #include <log.h>
 #include <pwm.h>
 #include <asm/io.h>
@@ -19,7 +20,6 @@ static int tegra_pwm_set_config(struct udevice *dev, uint channel,
 {
        struct tegra_pwm_priv *priv = dev_get_priv(dev);
        struct pwm_ctlr *regs = priv->regs;
-       const u32 pwm_max_freq = dev_get_driver_data(dev);
        uint pulse_width;
        u32 reg;
 
@@ -27,8 +27,6 @@ static int tegra_pwm_set_config(struct udevice *dev, uint channel,
                return -EINVAL;
        debug("%s: Configure '%s' channel %u\n", __func__, dev->name, channel);
 
-       clock_start_periph_pll(PERIPH_ID_PWM, CLOCK_ID_PERIPH, pwm_max_freq);
-
        pulse_width = duty_ns * 255 / period_ns;
 
        reg = pulse_width << PWM_WIDTH_SHIFT;
@@ -63,6 +61,22 @@ static int tegra_pwm_of_to_plat(struct udevice *dev)
        return 0;
 }
 
+static int tegra_pwm_probe(struct udevice *dev)
+{
+       const u32 pwm_max_freq = dev_get_driver_data(dev);
+       struct clk *clk;
+
+       clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(clk)) {
+               debug("%s: Could not get PWM clock: %ld\n", __func__, PTR_ERR(clk));
+               return PTR_ERR(clk);
+       }
+
+       clock_start_periph_pll(clk->id, CLOCK_ID_PERIPH, pwm_max_freq);
+
+       return 0;
+}
+
 static const struct pwm_ops tegra_pwm_ops = {
        .set_config     = tegra_pwm_set_config,
        .set_enable     = tegra_pwm_set_enable,
@@ -80,5 +94,6 @@ U_BOOT_DRIVER(tegra_pwm) = {
        .of_match = tegra_pwm_ids,
        .ops    = &tegra_pwm_ops,
        .of_to_plat     = tegra_pwm_of_to_plat,
+       .probe          = tegra_pwm_probe,
        .priv_auto      = sizeof(struct tegra_pwm_priv),
 };