[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1464942192-25967-9-git-send-email-boris.brezillon@free-electrons.com>
Date: Fri, 3 Jun 2016 10:23:06 +0200
From: Boris Brezillon <boris.brezillon@...e-electrons.com>
To: Thierry Reding <thierry.reding@...il.com>,
linux-pwm@...r.kernel.org, Mark Brown <broonie@...nel.org>,
Liam Girdwood <lgirdwood@...il.com>
Cc: Heiko Stuebner <heiko@...ech.de>,
linux-rockchip@...ts.infradead.org,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Milo Kim <milo.kim@...com>,
Doug Anderson <dianders@...gle.com>,
Caesar Wang <wxt@...k-chips.com>,
Stephen Barber <smbarber@...omium.org>,
Brian Norris <briannorris@...omium.org>,
Ajit Pal Singh <ajitpal.singh@...com>,
Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
Maxime Coquelin <maxime.coquelin@...com>,
Patrice Chotard <patrice.chotard@...com>, kernel@...inux.com,
Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH 08/14] pwm: sti: Avoid glitches on already running PWMs
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.brezillon@...e-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 6300d3e..8232c5b 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -340,7 +340,7 @@ 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)
@@ -391,7 +391,7 @@ 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;
@@ -409,6 +409,19 @@ 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 state;
+
+ pwm_get_state(&pc->chip.pwms[i], &state);
+ if (state.enabled)
+ clk_enable(pc->clk);
+ }
+ clk_disable(pc->clk);
+
platform_set_drvdata(pdev, pc);
return 0;
--
2.7.4
Powered by blists - more mailing lists