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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.

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Martin Blumenstingl 2019-06-12 21:59:00 +02:00 committed by Thierry Reding
parent ba4004c715
commit 181164b669
1 changed files with 6 additions and 2 deletions
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8
drivers/pwm/pwm-meson.c
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@ -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);