linux-kernel - [PATCH 1/6] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1477259146-19167-2-git-send-email-l.majewski@majess.pl>
Date:   Sun, 23 Oct 2016 23:45:41 +0200
From:   Lukasz Majewski <l.majewski@...ess.pl>
To:     Thierry Reding <thierry.reding@...il.com>,
        Stefan Agner <stefan@...er.ch>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>
Cc:     linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Fabio Estevam <fabio.estevam@....com>,
        Fabio Estevam <festevam@...il.com>,
        Lothar Wassmann <LW@...o-electronics.de>,
        Bhuvanchandra DV <bhuvanchandra.dv@...adex.com>,
        kernel@...gutronix.de, Lukasz Majewski <l.majewski@...ess.pl>
Subject: [PATCH 1/6] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

The code has been rewritten to remove "generic" calls to
imx_pwm_{enable|disable|config}.

Such approach would facilitate switch to atomic PWM (a.k.a ->apply())
implementation.

Suggested-by: Stefan Agner <stefan@...er.ch>
Suggested-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Signed-off-by: Lukasz Majewski <l.majewski@...ess.pl>
---
 drivers/pwm/pwm-imx.c | 46 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index c37d223..83e43d5 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -66,8 +66,6 @@ struct imx_chip {
 static int imx_pwm_config_v1(struct pwm_chip *chip,
 		struct pwm_device *pwm, int duty_ns, int period_ns)
 {
-	struct imx_chip *imx = to_imx_chip(chip);
-
 	/*
 	 * The PWM subsystem allows for exact frequencies. However,
 	 * I cannot connect a scope on my device to the PWM line and
@@ -85,26 +83,52 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
 	 * both the prescaler (/1 .. /128) and then by CLKSEL
 	 * (/2 .. /16).
 	 */
+	struct imx_chip *imx = to_imx_chip(chip);
 	u32 max = readl(imx->mmio_base + MX1_PWMP);
 	u32 p = max * duty_ns / period_ns;
+	int ret;
+
+	ret = clk_prepare_enable(imx->clk_ipg);
+	if (ret)
+		return ret;
+
 	writel(max - p, imx->mmio_base + MX1_PWMS);
 
+	clk_disable_unprepare(imx->clk_ipg);
+
 	return 0;
 }
 
-static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
+static int imx_pwm_enable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct imx_chip *imx = to_imx_chip(chip);
+	int ret;
 	u32 val;
 
+	ret = clk_prepare_enable(imx->clk_ipg);
+	if (ret)
+		return ret;
+
 	val = readl(imx->mmio_base + MX1_PWMC);
+	val |= MX1_PWMC_EN;
+	writel(val, imx->mmio_base + MX1_PWMC);
 
-	if (enable)
-		val |= MX1_PWMC_EN;
-	else
-		val &= ~MX1_PWMC_EN;
+	clk_disable_unprepare(imx->clk_per);
+
+	return 0;
+}
+
+static void imx_pwm_disable_v1(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct imx_chip *imx = to_imx_chip(chip);
+	u32 val;
+
+	val = readl(imx->mmio_base + MX1_PWMC);
+	val &= ~MX1_PWMC_EN;
 
 	writel(val, imx->mmio_base + MX1_PWMC);
+
+	clk_disable_unprepare(imx->clk_per);
 }
 
 static int imx_pwm_config_v2(struct pwm_chip *chip,
@@ -269,9 +293,9 @@ static int imx_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
 }
 
 static struct pwm_ops imx_pwm_ops_v1 = {
-	.enable = imx_pwm_enable,
-	.disable = imx_pwm_disable,
-	.config = imx_pwm_config,
+	.enable = imx_pwm_enable_v1,
+	.disable = imx_pwm_disable_v1,
+	.config = imx_pwm_config_v1,
 	.owner = THIS_MODULE,
 };
 
@@ -291,8 +315,6 @@ struct imx_pwm_data {
 };
 
 static struct imx_pwm_data imx_pwm_data_v1 = {
-	.config = imx_pwm_config_v1,
-	.set_enable = imx_pwm_set_enable_v1,
 	.pwm_ops = &imx_pwm_ops_v1,
 };
 
-- 
2.1.4