Re: [PATCH v5 3/3] pwm: mtk_disp: implement atomic API .get_state()
From: Uwe Kleine-König <hidden>
Date: 2021-06-25 17:59:19
Also in:
linux-mediatek, linux-pwm, lkml
On Wed, Jun 16, 2021 at 04:52:24PM +0800, Jitao Shi wrote:
quoted hunk ↗ jump to hunk
Switch the driver to support the .get_state() method. Signed-off-by: Jitao Shi <redacted> --- drivers/pwm/pwm-mtk-disp.c | 39 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c index a4766e931b68..d60a6b379683 100644 --- a/drivers/pwm/pwm-mtk-disp.c +++ b/drivers/pwm/pwm-mtk-disp.c@@ -159,8 +159,47 @@ static int mtk_disp_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return 0; } +static void mtk_disp_pwm_get_state(struct pwm_chip *chip, + struct pwm_device *pwm, + struct pwm_state *state) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + u32 clk_div, con0, con1; + u64 rate, period, high_width; + int err; + + if (!mdp->enabled) { + err = clk_prepare_enable(mdp->clk_main); + if (err < 0) { + dev_err(chip->dev, "Can't enable mdp->clk_main: %pe\n", ERR_PTR(err)); + return; + } + err = clk_prepare_enable(mdp->clk_mm); + if (err < 0) { + dev_err(chip->dev, "Can't enable mdp->clk_mm: %pe\n", ERR_PTR(err)); + clk_disable_unprepare(mdp->clk_main); + return; + } + }
As already written in reply to one of the previous patches: The clk_prepare_enable() can be done unconditionally.
+ rate = clk_get_rate(mdp->clk_main); + con0 = readl(mdp->base + mdp->data->con0); + con1 = readl(mdp->base + mdp->data->con1); + state->enabled = !!(con0 & BIT(0));
Maybe introduce a name for that.
+ clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0); + period = con1 & PWM_PERIOD_MASK;
FIELD_GET(PWM_PERIOD_MASK, con1) for consistency.
+ state->period = DIV64_U64_ROUND_UP(period * (clk_div + 1) * NSEC_PER_SEC, rate);
period has 12 bits, clk_div 11 and NSEC_PER_SEC has 30, so this cannot overflow. Maybe mention this in a comment.
+ high_width = FIELD_GET(PWM_HIGH_WIDTH_MASK, con1); + state->duty_cycle = DIV64_U64_ROUND_UP(high_width * (clk_div + 1) * NSEC_PER_SEC, + rate);
state->polarity = PWM_POLARITY_NORMAL;
+ if (!mdp->enabled) {
+ clk_disable_unprepare(mdp->clk_mm);
+ clk_disable_unprepare(mdp->clk_main);
+ }
+}
+
static const struct pwm_ops mtk_disp_pwm_ops = {
.apply = mtk_disp_pwm_apply,
+ .get_state = mtk_disp_pwm_get_state,
.owner = THIS_MODULE,
};Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |