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authorZhi Mao <zhi.mao@mediatek.com>2017-06-30 14:05:18 +0800
committerThierry Reding <thierry.reding@gmail.com>2017-08-21 10:39:09 +0200
commite7c197ec97c3ac3ed3698be7a21d51a338582e1d (patch)
treee415c1bd31064ae802eb4b92d4a3b3f3cf9a204b /drivers/pwm
parentcd30798a6c17c1fa182e9b0bb85bd973776ff193 (diff)
downloadlinux-e7c197ec97c3ac3ed3698be7a21d51a338582e1d.tar.bz2
pwm: mediatek: Fix clock control issue
In order to save some power, do not prepare the top and main clocks during mtk_pwm_probe(). Instead, prepare the clocks only when necessary and also make sure to enable the clocks to match the semantics of the common clock framework. While at it, don't explicitly disable all PWM channels in ->remove() because all users should have done that already. Signed-off-by: Zhi Mao <zhi.mao@mediatek.com> Acked-by: John Crispin <john@phrozen.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-mediatek.c69
1 files changed, 47 insertions, 22 deletions
diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index d08b5b3dca71..637045998318 100644
--- a/drivers/pwm/pwm-mediatek.c
+++ b/drivers/pwm/pwm-mediatek.c
@@ -2,6 +2,7 @@
* Mediatek Pulse Width Modulator driver
*
* Copyright (C) 2015 John Crispin <blogic@openwrt.org>
+ * Copyright (C) 2017 Zhi Mao <zhi.mao@mediatek.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
@@ -61,6 +62,42 @@ static inline struct mtk_pwm_chip *to_mtk_pwm_chip(struct pwm_chip *chip)
return container_of(chip, struct mtk_pwm_chip, chip);
}
+static int mtk_pwm_clk_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
+ int ret;
+
+ ret = clk_prepare_enable(pc->clks[MTK_CLK_TOP]);
+ if (ret < 0)
+ return ret;
+
+ ret = clk_prepare_enable(pc->clks[MTK_CLK_MAIN]);
+ if (ret < 0)
+ goto disable_clk_top;
+
+ ret = clk_prepare_enable(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
+ if (ret < 0)
+ goto disable_clk_main;
+
+ return 0;
+
+disable_clk_main:
+ clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
+disable_clk_top:
+ clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
+
+ return ret;
+}
+
+static void mtk_pwm_clk_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
+
+ clk_disable_unprepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
+ clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
+ clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
+}
+
static inline u32 mtk_pwm_readl(struct mtk_pwm_chip *chip, unsigned int num,
unsigned int offset)
{
@@ -80,6 +117,11 @@ static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
struct clk *clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm];
u32 resolution, clkdiv = 0;
+ int ret;
+
+ ret = mtk_pwm_clk_enable(chip, pwm);
+ if (ret < 0)
+ return ret;
resolution = NSEC_PER_SEC / clk_get_rate(clk);
@@ -95,6 +137,8 @@ static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
mtk_pwm_writel(pc, pwm->hwpwm, PWMDWIDTH, period_ns / resolution);
mtk_pwm_writel(pc, pwm->hwpwm, PWMTHRES, duty_ns / resolution);
+ mtk_pwm_clk_disable(chip, pwm);
+
return 0;
}
@@ -104,7 +148,7 @@ static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
u32 value;
int ret;
- ret = clk_prepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
+ ret = mtk_pwm_clk_enable(chip, pwm);
if (ret < 0)
return ret;
@@ -124,7 +168,7 @@ static void mtk_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
value &= ~BIT(pwm->hwpwm);
writel(value, pc->regs);
- clk_unprepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
+ mtk_pwm_clk_disable(chip, pwm);
}
static const struct pwm_ops mtk_pwm_ops = {
@@ -156,14 +200,6 @@ static int mtk_pwm_probe(struct platform_device *pdev)
return PTR_ERR(pc->clks[i]);
}
- ret = clk_prepare(pc->clks[MTK_CLK_TOP]);
- if (ret < 0)
- return ret;
-
- ret = clk_prepare(pc->clks[MTK_CLK_MAIN]);
- if (ret < 0)
- goto disable_clk_top;
-
platform_set_drvdata(pdev, pc);
pc->chip.dev = &pdev->dev;
@@ -174,26 +210,15 @@ static int mtk_pwm_probe(struct platform_device *pdev)
ret = pwmchip_add(&pc->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
- goto disable_clk_main;
+ return ret;
}
return 0;
-
-disable_clk_main:
- clk_unprepare(pc->clks[MTK_CLK_MAIN]);
-disable_clk_top:
- clk_unprepare(pc->clks[MTK_CLK_TOP]);
-
- return ret;
}
static int mtk_pwm_remove(struct platform_device *pdev)
{
struct mtk_pwm_chip *pc = platform_get_drvdata(pdev);
- unsigned int i;
-
- for (i = 0; i < pc->chip.npwm; i++)
- pwm_disable(&pc->chip.pwms[i]);
return pwmchip_remove(&pc->chip);
}