0001-pwm-rockchip-Keep-enabled-PWMs-running-while-probing.patch

From 7599750a79d17f2554abb71a95dd724f5e9efa57 Mon Sep 17 00:00:00 2001
From: Simon South <simon@simonsouth.net>
Date: Fri, 18 Sep 2020 13:51:46 -0400
Subject: [PATCH] pwm: rockchip: Keep enabled PWMs running while probing

Following commit cfc4c18 ("pwm: Read initial hardware state at request
time") the Rockchip PWM driver can no longer assume a device's state
information has been populated after a call to pwmchip_add().
Consequently, the test in rockchip_pwm_probe() intended to prevent the
driver from stopping PWM devices already enabled by the bootloader no
longer functions reliably and can lead to the kernel hanging during
startup.

With this change the driver explicitly fetches the state of a device
before attempting to determine whether or not it is enabled, fixing
this issue.

Signed-off-by: Simon South <simon@simonsouth.net>
---
 drivers/pwm/pwm-rockchip.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index eb8c9cb64..098e94335 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -288,6 +288,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	const struct of_device_id *id;
 	struct rockchip_pwm_chip *pc;
 	struct resource *r;
+	u32 enable_conf, ctrl;
 	int ret, count;
 
 	id = of_match_device(rockchip_pwm_dt_ids, &pdev->dev);
@@ -362,7 +363,9 @@ static int rockchip_pwm_probe(struct platform_device *pdev)
 	}
 
 	/* Keep the PWM clk enabled if the PWM appears to be up and running. */
-	if (!pwm_is_enabled(pc->chip.pwms))
+	enable_conf = pc->data->enable_conf;
+	ctrl = readl_relaxed(pc->base + pc->data->regs.ctrl);
+	if ((ctrl & enable_conf) != enable_conf)
 		clk_disable(pc->clk);
 
 	return 0;
-- 
2.28.0