Hi
comments inline
On 21/06/17 10:11, Zhi Mao wrote:
1.fix clock control
- prepare top/main clk in mtk_pwm_probe() function,
it will increase power consumption
and in original code these clocks is only prepeare but never enabled
- pwm clock should be enabled before setting pwm registers
in function: mtk_pwm_config()
2.fix pwm source clock selection
- in original code, the pwm output frequency is not correct
when set bit<3>=1 to PWMCON register.
Signed-off-by: Zhi Mao <zhi.mao@xxxxxxxxxxxx>
---
drivers/pwm/pwm-mediatek.c | 69 +++++++++++++++++++++++++++-----------------
1 file changed, 43 insertions(+), 26 deletions(-)
diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c
index 5c11bc7..c803ff6 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@xxxxxxxxxxx>
+ * Copyright (C) 2017 Zhi Mao <zhi.mao@xxxxxxxxxxxx>
*
* 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 +62,40 @@ 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 = 0;
+
+ 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) {
+ clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
+ return ret;
+ }
+
+ ret = clk_prepare_enable(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
+ if (ret < 0) {
+ clk_disable_unprepare(pc->clks[MTK_CLK_MAIN]);
+ clk_disable_unprepare(pc->clks[MTK_CLK_TOP]);
+ return ret;
+ }
+
Rather than disabling the already prepared clks in each error path and
then returning, you should use goto err_clk_{top,main,pwm1} in the same
style as what this patch removes from mtk_pwm_probe()
+ 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)
{
@@ -81,6 +116,8 @@ static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
struct clk *clk = pc->clks[MTK_CLK_PWM1 + pwm->hwpwm];
u32 resolution, clkdiv = 0;
+ mtk_pwm_clk_enable(chip, pwm);
+
resolution = NSEC_PER_SEC / clk_get_rate(clk);
while (period_ns / resolution > 8191) {
@@ -91,10 +128,12 @@ static int mtk_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
if (clkdiv > 7)
return -EINVAL;
- mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | BIT(3) | clkdiv);
+ mtk_pwm_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
this chunk needs to go into its own patch
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;
}
@@ -102,11 +141,8 @@ static int mtk_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct mtk_pwm_chip *pc = to_mtk_pwm_chip(chip);
u32 value;
- int ret;
- ret = clk_prepare(pc->clks[MTK_CLK_PWM1 + pwm->hwpwm]);
- if (ret < 0)
- return ret;
+ mtk_pwm_clk_enable(chip, pwm);
You need to check the error code here and return if clk enabling failed
value = readl(pc->regs);
value |= BIT(pwm->hwpwm);
@@ -124,7 +160,7 @@ 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 +192,6 @@ 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 +202,15 @@ 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]);
why are you removing this chunk ?
John
return pwmchip_remove(&pc->chip);
}
--
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