[PATCH v2 03/10] pwm: imx: Rewrite imx_pwm_*_v1 code to facilitate switch to atomic pwm operation

[Lukasz Majewski]

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 <ste...@agner.ch>
Suggested-by: Boris Brezillon <boris.brezil...@free-electrons.com>
Signed-off-by: Lukasz Majewski <l.majew...@majess.pl>
---
Changes for v2:
- Add missing clock unprepare for clk_ipg
- Enable peripheral PWM clock (clk_per)
---
 drivers/pwm/pwm-imx.c | 50 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 38 insertions(+), 12 deletions(-)

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index ea3ce79..822eb5a 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -65,8 +65,6 @@ 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
@@ -84,26 +82,56 @@ 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;
+
+       ret = clk_prepare_enable(imx->clk_per);
+       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_ipg);
+
+       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,
@@ -241,9 +269,9 @@ static void imx_pwm_disable(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,
 };
 
@@ -262,8 +290,6 @@ 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