[RFC 06/19] devfreq: imx8m-ddrc: Add late system sleep PM ops

Abel Vesa
2021-09-13T17:38:56Z

Seems that, in order to be able to resume from suspend, the dram rate
needs to be the highest one available. Therefore, add the late system
suspend/resume PM ops which set the highest rate on suspend and the
latest one used before suspending on resume.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
drivers/devfreq/imx8m-ddrc.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/drivers/devfreq/imx8m-ddrc.c b/drivers/devfreq/imx8m-ddrc.c
index f18a5c3c1c03..f39741b4a0b0 100644
--- a/drivers/devfreq/imx8m-ddrc.c
+++ b/drivers/devfreq/imx8m-ddrc.c
@@ -72,6 +72,8 @@ struct imx8m_ddrc {
struct clk *dram_alt;
struct clk *dram_apb;

+ unsigned long suspend_rate;
+ unsigned long resume_rate;
int freq_count;
struct imx8m_ddrc_freq freq_table[IMX8M_DDRC_MAX_FREQ_COUNT];
};
@@ -271,6 +273,22 @@ static int imx8m_ddrc_target(struct device *dev, unsigned long *freq, u32 flags)
return ret;
}

+static int imx8m_ddrc_suspend(struct device *dev)
+{
+ struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+
+ priv->resume_rate = clk_get_rate(priv->dram_core);
+
+ return imx8m_ddrc_target(dev, &priv->suspend_rate, 0);
+}
+
+static int imx8m_ddrc_resume(struct device *dev)
+{
+ struct imx8m_ddrc *priv = dev_get_drvdata(dev);
+
+ return imx8m_ddrc_target(dev, &priv->resume_rate, 0);
+}
+
static int imx8m_ddrc_get_cur_freq(struct device *dev, unsigned long *freq)
{
struct imx8m_ddrc *priv = dev_get_drvdata(dev);
@@ -324,6 +342,9 @@ static int imx8m_ddrc_init_freq_info(struct device *dev)

if (dev_pm_opp_add(dev, freq->rate * 250000, 0))
return -ENODEV;
+
+ if (index == 0)
+ priv->suspend_rate = freq->rate * 250000;
}

return 0;
@@ -399,11 +420,16 @@ static const struct of_device_id imx8m_ddrc_of_match[] = {
};
MODULE_DEVICE_TABLE(of, imx8m_ddrc_of_match);

+static const struct dev_pm_ops imx8m_ddrc_pm_ops = {
+ SET_LATE_SYSTEM_SLEEP_PM_OPS(imx8m_ddrc_suspend, imx8m_ddrc_resume)
+};
+
static struct platform_driver imx8m_ddrc_platdrv = {
.probe = imx8m_ddrc_probe,
.driver = {
.name = "imx8m-ddrc-devfreq",
- .of_match_table = imx8m_ddrc_of_match,
+ .pm = &imx8m_ddrc_pm_ops,
+ .of_match_table = of_match_ptr(imx8m_ddrc_of_match),
},
};
module_platform_driver(imx8m_ddrc_platdrv);
--
2.31.1