The current logic will disable the PWM clk even if a PWM was left
enabled by the bootloader (because it's controlling a critical device
like a regulator for example).
Keep the PWM clk enabled if at least one PWM is enabled to avoid any
glitches.

Signed-off-by: Boris Brezillon <boris.brezil...@free-electrons.com>
---
 drivers/pwm/pwm-sti.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 0fbca94..bea1d17 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -343,7 +343,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
        struct sti_pwm_compat_data *cdata;
        struct sti_pwm_chip *pc;
        struct resource *res;
-       int ret;
+       int i, ret;
 
        pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
        if (!pc)
@@ -394,7 +394,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
-       ret = clk_prepare(pc->clk);
+       ret = clk_prepare_enable(pc->clk);
        if (ret) {
                dev_err(dev, "failed to prepare clock\n");
                return ret;
@@ -412,6 +412,19 @@ static int sti_pwm_probe(struct platform_device *pdev)
                return ret;
        }
 
+       /*
+        * Keep the PWM clk enabled if some PWMs appear to be up and
+        * running.
+        */
+       for (i = 0; i < pc->chip.npwm; i++) {
+               struct pwm_state pstate;
+
+               pwm_get_state(&pc->chip.pwms[i], &pstate);
+               if (pstate.enabled)
+                       clk_enable(pc->clk);
+       }
+       clk_disable(pc->clk);
+
        platform_set_drvdata(pdev, pc);
 
        return 0;
-- 
2.5.0

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to