[PATCH v5 06/17] i3c: renesas: Perform Dynamic Address Assignment on resume

[Claudiu Beznea]

From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>

The Renesas RZ/G3S SoC supports a power saving mode where power to most
SoC components, including I3C, is turned off.

On systems where the I3C devices also loses power during suspend (e.g. NXP
P3T1085UK-ARD connected to the PMOD1_6A connector of the RZ SMARC Carrier
2 + Renesas RZ/G3S SMARC SOM), the devices becomes unreachable after
resume.

Running DAA in the controller resume path restores communication. However,
DAA relies on interrupts for TX/RX, which are not available in the noirq
suspend/resume phase (unless they are wakeup interrupts). For this, the
suspend/resume callbacks were moved out of the noirq phase. Currently,
there is no identified use case on either the Renesas RZ/G3S or Renesas
RZ/G3E SoCs that requires the controller suspend/resume hooks to be part of
the noirq suspend/resume phase.

Since renesas_i3c_reset() is not called anymore in atomic context
update it to use read_poll_timeout().

Along with this, struct renesas_i3c::DATBASn and its usage were removed,
as they are no longer needed.

Fixes: e7218986319b ("i3c: renesas: Add suspend/resume support")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---

Changes in v5:
- restore it to the level of v1; the other scenarios updated by
  sashiko were already present w/ and w/o this patch and could be
  addressed incrementally
- updated the patch description

Changes in v4:
- used directly i3c_dev instead of i3c_dev->dev->desc
- fixed the swap in renesas_i3c_group_devs_in_slots() for i3c->addr[]

Changes in v3:
- added renesas_i3c_group_devs_in_slots(); along with it, the
  struct renesas_i3c_addr was updated with i3c_dev and i3c_dev
  and the attach/detach/re-attach APIs were adjusted accordingly
- dropped DATBASn member of struct renesas_i3c
- used i3c_master_reattach_i3c_dev_locked() to re-attach devices
  on a fully occupied bus
- in resume, moved i2c_mark_adapter_resumed() after i3c_master_do_daa_ext()
  since it can update the internal driver data structure i2c specific

Changes in v2:
- adjusted the code to still work in case the full bus was occupied before
  a suspend/resume cycle; for that:
-- introduced struct renesas_i3c_addr
-- preserved i3c->DATBASn[] which is saved in suspend and used in resume,
   in renesas_i3c_daa()
- updated the patch description to reflect the new updates

 drivers/i3c/master/renesas-i3c.c | 38 +++++++++++++-------------------
 1 file changed, 15 insertions(+), 23 deletions(-)

diff --git a/drivers/i3c/master/renesas-i3c.c b/drivers/i3c/master/renesas-i3c.c
index 6590da962592..acc30ed615ab 100644
--- a/drivers/i3c/master/renesas-i3c.c
+++ b/drivers/i3c/master/renesas-i3c.c
@@ -265,7 +265,6 @@ struct renesas_i3c {
 	u8 addrs[RENESAS_I3C_MAX_DEVS];
 	struct renesas_i3c_xferqueue xferqueue;
 	void __iomem *regs;
-	u32 *DATBASn;
 	struct clk_bulk_data *clks;
 	struct reset_control *presetn;
 	struct reset_control *tresetn;
@@ -495,8 +494,8 @@ static int renesas_i3c_reset(struct renesas_i3c *i3c)
 	renesas_writel(i3c->regs, BCTL, 0);
 	renesas_set_bit(i3c->regs, RSTCTL, RSTCTL_RI3CRST);
 
-	return read_poll_timeout_atomic(renesas_readl, val, !(val & RSTCTL_RI3CRST),
-					0, 1000, false, i3c->regs, RSTCTL);
+	return read_poll_timeout(renesas_readl, val, !(val & RSTCTL_RI3CRST),
+				 0, 1000, false, i3c->regs, RSTCTL);
 }
 
 static void renesas_i3c_hw_init(struct renesas_i3c *i3c)
@@ -1419,12 +1418,6 @@ static int renesas_i3c_probe(struct platform_device *pdev)
 	i3c->maxdevs = RENESAS_I3C_MAX_DEVS;
 	i3c->free_pos = GENMASK(i3c->maxdevs - 1, 0);
 
-	/* Allocate dynamic Device Address Table backup. */
-	i3c->DATBASn = devm_kzalloc(&pdev->dev, sizeof(u32) * i3c->maxdevs,
-				    GFP_KERNEL);
-	if (!i3c->DATBASn)
-		return -ENOMEM;
-
 	return i3c_master_register(&i3c->base, &pdev->dev, &renesas_i3c_ops, false);
 }
 
@@ -1435,17 +1428,13 @@ static void renesas_i3c_remove(struct platform_device *pdev)
 	i3c_master_unregister(&i3c->base);
 }
 
-static int renesas_i3c_suspend_noirq(struct device *dev)
+static int renesas_i3c_suspend(struct device *dev)
 {
 	struct renesas_i3c *i3c = dev_get_drvdata(dev);
-	int i, ret;
+	int ret;
 
 	i2c_mark_adapter_suspended(&i3c->base.i2c);
 
-	/* Store Device Address Table values. */
-	for (i = 0; i < i3c->maxdevs; i++)
-		i3c->DATBASn[i] = renesas_readl(i3c->regs, DATBAS(i));
-
 	ret = reset_control_assert(i3c->presetn);
 	if (ret)
 		goto err_mark_resumed;
@@ -1466,10 +1455,10 @@ static int renesas_i3c_suspend_noirq(struct device *dev)
 	return ret;
 }
 
-static int renesas_i3c_resume_noirq(struct device *dev)
+static int renesas_i3c_resume(struct device *dev)
 {
 	struct renesas_i3c *i3c = dev_get_drvdata(dev);
-	int i, ret;
+	int ret;
 
 	ret = reset_control_deassert(i3c->tresetn);
 	if (ret)
@@ -1495,15 +1484,19 @@ static int renesas_i3c_resume_noirq(struct device *dev)
 	renesas_writel(i3c->regs, MSDVAD, MSDVAD_MDYADV |
 		       MSDVAD_MDYAD(i3c->dyn_addr));
 
-	/* Restore Device Address Table values. */
-	for (i = 0; i < i3c->maxdevs; i++)
-		renesas_writel(i3c->regs, DATBAS(i), i3c->DATBASn[i]);
-
 	/* I3C hw init. */
 	renesas_i3c_hw_init(i3c);
 
+	ret = i3c_master_do_daa_ext(&i3c->base, true);
+	if (ret)
+		dev_err(dev, "DAA failed on resume, ret=%d", ret);
+
 	i2c_mark_adapter_resumed(&i3c->base.i2c);
 
+	/*
+	 * I3C devices may have retained their dynamic address anyway. Do not
+	 * fail the resume because of DAA error.
+	 */
 	return 0;
 
 err_clks_disable:
@@ -1516,8 +1509,7 @@ static int renesas_i3c_resume_noirq(struct device *dev)
 }
 
 static const struct dev_pm_ops renesas_i3c_pm_ops = {
-	NOIRQ_SYSTEM_SLEEP_PM_OPS(renesas_i3c_suspend_noirq,
-				  renesas_i3c_resume_noirq)
+	SYSTEM_SLEEP_PM_OPS(renesas_i3c_suspend, renesas_i3c_resume)
 };
 
 static const struct of_device_id renesas_i3c_of_ids[] = {
-- 
2.43.0