linux-kernel - [PATCH 03/14] pwm: meson: use GENMASK and FIELD

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: <20190525181133.4875-4-martin.blumenstingl@googlemail.com>
Date:   Sat, 25 May 2019 20:11:22 +0200
From:   Martin Blumenstingl <martin.blumenstingl@...glemail.com>
To:     linux-amlogic@...ts.infradead.org, linux-pwm@...r.kernel.org,
        thierry.reding@...il.com, u.kleine-koenig@...gutronix.de
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Subject: [PATCH 03/14] pwm: meson: use GENMASK and FIELD_PREP for the lo and hi values

meson_pwm_calc() ensures that "lo" is always less than 16 bits wide
(otherwise it would overflow into the "hi" part of the REG_PWM_{A,B}
register).
Use GENMASK and FIELD_PREP for the lo and hi values to make it easier to
spot how wide these are internally. Additionally this is a preparation
step for the .get_state() implementation where the GENMASK() for lo and
hi becomes handy because it can be used with FIELD_GET() to extract the
values from the register REG_PWM_{A,B} register.

No functional changes intended.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
---
 drivers/pwm/pwm-meson.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index 35b38c7201c3..c62a3ac924d0 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -5,6 +5,8 @@
  * Copyright (C) 2014 Amlogic, Inc.
  */
 
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/err.h>
@@ -20,7 +22,8 @@
 
 #define REG_PWM_A		0x0
 #define REG_PWM_B		0x4
-#define PWM_HIGH_SHIFT		16
+#define PWM_LOW_MASK		GENMASK(15, 0)
+#define PWM_HIGH_MASK		GENMASK(31, 16)
 
 #define REG_MISC_AB		0x8
 #define MISC_B_CLK_EN		BIT(23)
@@ -217,7 +220,8 @@ static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm)
 	value |= clk_enable;
 	writel(value, meson->base + REG_MISC_AB);
 
-	value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
+	value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
+		FIELD_PREP(PWM_LOW_MASK, channel->lo);
 	writel(value, meson->base + offset);
 
 	value = readl(meson->base + REG_MISC_AB);
-- 
2.21.0