i3c: master: svc: fix i3c suspend/resume issue

Commit Message

Clark Wang May 17, 2023, 3:30 a.m. UTC

When system suspends, if i3c module is powered down, register
value will lose.
Need to save the key registers before system suspend.
So save these registers value in runtime pm suspend, and restore them
if these register's value is different with the saved values
when runtime pm resume.

Signed-off-by: Clark Wang <[e-mail]>
---
 drivers/i3c/master/svc-i3c-master.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Miquel Raynal May 22, 2023, 8:31 a.m. UTC | #1

Hi Clark,

[e-mail] wrote on Wed, 17 May 2023 11:30:28 +0800:

> When system suspends, if i3c module is powered down, register
> value will lose.
> Need to save the key registers before system suspend.
> So save these registers value in runtime pm suspend, and restore them
> if these register's value is different with the saved values
> when runtime pm resume.
> 
> Signed-off-by: Clark Wang <[e-mail]>

Reviewed-by: Miquel Raynal <[e-mail]>

Thanks,
Miquèl

Alexandre Belloni June 4, 2023, 10:52 p.m. UTC | #2

On Wed, 17 May 2023 11:30:28 +0800, Clark Wang wrote:
> When system suspends, if i3c module is powered down, register
> value will lose.
> Need to save the key registers before system suspend.
> So save these registers value in runtime pm suspend, and restore them
> if these register's value is different with the saved values
> when runtime pm resume.
> 
> [...]

Applied, thanks!

[1/1] i3c: master: svc: fix i3c suspend/resume issue
      commit: 1c5ee2a77b1bacd4c333bebea93610aaf17977be

Patch

diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
index e3f454123805..bca3a4352ad1 100644
--- a/drivers/i3c/master/svc-i3c-master.c
+++ b/drivers/i3c/master/svc-i3c-master.c
@@ -145,6 +145,11 @@  struct svc_i3c_xfer {
 	struct svc_i3c_cmd cmds[];
 };
 
+struct svc_i3c_regs_save {
+	u32 mconfig;
+	u32 mdynaddr;
+};
+
 /**
  * struct svc_i3c_master - Silvaco I3C Master structure
  * @base: I3C master controller
@@ -173,6 +178,7 @@  struct svc_i3c_master {
 	struct i3c_master_controller base;
 	struct device *dev;
 	void __iomem *regs;
+	struct svc_i3c_regs_save saved_regs;
 	u32 free_slots;
 	u8 addrs[SVC_I3C_MAX_DEVS];
 	struct i3c_dev_desc *descs[SVC_I3C_MAX_DEVS];
@@ -1579,10 +1585,28 @@  static void svc_i3c_master_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+static void svc_i3c_save_regs(struct svc_i3c_master *master)
+{
+	master->saved_regs.mconfig = readl(master->regs + SVC_I3C_MCONFIG);
+	master->saved_regs.mdynaddr = readl(master->regs + SVC_I3C_MDYNADDR);
+}
+
+static void svc_i3c_restore_regs(struct svc_i3c_master *master)
+{
+	if (readl(master->regs + SVC_I3C_MDYNADDR) !=
+	    master->saved_regs.mdynaddr) {
+		writel(master->saved_regs.mconfig,
+		       master->regs + SVC_I3C_MCONFIG);
+		writel(master->saved_regs.mdynaddr,
+		       master->regs + SVC_I3C_MDYNADDR);
+	}
+}
+
 static int __maybe_unused svc_i3c_runtime_suspend(struct device *dev)
 {
 	struct svc_i3c_master *master = dev_get_drvdata(dev);
 
+	svc_i3c_save_regs(master);
 	svc_i3c_master_unprepare_clks(master);
 	pinctrl_pm_select_sleep_state(dev);
 
@@ -1596,6 +1620,8 @@  static int __maybe_unused svc_i3c_runtime_resume(struct device *dev)
 	pinctrl_pm_select_default_state(dev);
 	svc_i3c_master_prepare_clks(master);
 
+	svc_i3c_restore_regs(master);
+
 	return 0;
 }