[PATCH 4/8] soc: ti: omap-prm: add support for denying idle for reset clockdomain

[Tero Kristo <t-kristo@xxxxxx>]

TI SoCs hardware reset signals require the parent clockdomain to be
in force wakeup mode while de-asserting the reset, otherwise it may
never complete. To support this, add pdata hooks to control the
clockdomain directly.

Signed-off-by: Tero Kristo <t-kristo@xxxxxx>
---
 drivers/soc/ti/omap_prm.c            | 32 ++++++++++++++++++++++++++++----
 include/linux/platform_data/ti-prm.h | 21 +++++++++++++++++++++
 2 files changed, 49 insertions(+), 4 deletions(-)
 create mode 100644 include/linux/platform_data/ti-prm.h

diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
index d412af3..870515e3 100644
--- a/drivers/soc/ti/omap_prm.c
+++ b/drivers/soc/ti/omap_prm.c
@@ -16,6 +16,8 @@
 #include <linux/reset-controller.h>
 #include <linux/delay.h>
 
+#include <linux/platform_data/ti-prm.h>
+
 struct omap_rst_map {
 	s8 rst;
 	s8 st;
@@ -24,6 +26,7 @@ struct omap_rst_map {
 struct omap_prm_data {
 	u32 base;
 	const char *name;
+	const char *clkdm_name;
 	u16 pwstctrl;
 	u16 pwstst;
 	u16 rstctl;
@@ -40,6 +43,8 @@ struct omap_prm {
 struct omap_reset_data {
 	struct reset_controller_dev rcdev;
 	struct omap_prm *prm;
+	struct clockdomain *clkdm;
+	struct device *dev;
 };
 
 #define to_omap_reset_data(p) container_of((p), struct omap_reset_data, rcdev)
@@ -108,6 +113,8 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
 	int st_bit = id;
 	bool has_rstst;
 	int timeout = 0;
+	struct ti_prm_platform_data *pdata = dev_get_platdata(reset->dev);
+	int ret = 0;
 
 	/* check the current status to avoid de-asserting the line twice */
 	v = readl_relaxed(reset->prm->base + reset->prm->data->rstctl);
@@ -125,13 +132,16 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
 		writel_relaxed(v, reset->prm->base + reset->prm->data->rstst);
 	}
 
+	if (pdata->clkdm_deny_idle && reset->clkdm)
+		pdata->clkdm_deny_idle(reset->clkdm);
+
 	/* de-assert the reset control line */
 	v = readl_relaxed(reset->prm->base + reset->prm->data->rstctl);
 	v &= ~(1 << id);
 	writel_relaxed(v, reset->prm->base + reset->prm->data->rstctl);
 
 	if (!has_rstst)
-		return 0;
+		goto exit;
 
 	/* wait for the status to be set */
 	while (1) {
@@ -140,13 +150,19 @@ static int omap_reset_deassert(struct reset_controller_dev *rcdev,
 		if (v)
 			break;
 		timeout++;
-		if (timeout > OMAP_RESET_MAX_WAIT)
-			return -EBUSY;
+		if (timeout > OMAP_RESET_MAX_WAIT) {
+			ret = -EBUSY;
+			goto exit;
+		}
 
 		udelay(1);
 	}
 
-	return 0;
+exit:
+	if (pdata->clkdm_allow_idle && reset->clkdm)
+		pdata->clkdm_allow_idle(reset->clkdm);
+
+	return ret;
 }
 
 static const struct reset_control_ops omap_reset_ops = {
@@ -159,6 +175,8 @@ static int omap_prm_reset_probe(struct platform_device *pdev,
 				struct omap_prm *prm)
 {
 	struct omap_reset_data *reset;
+	struct ti_prm_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	char buf[32];
 
 	/*
 	 * Check if we have resets. If either rstctl or rstst is
@@ -177,9 +195,15 @@ static int omap_prm_reset_probe(struct platform_device *pdev,
 	reset->rcdev.ops = &omap_reset_ops;
 	reset->rcdev.of_node = pdev->dev.of_node;
 	reset->rcdev.nr_resets = OMAP_MAX_RESETS;
+	reset->dev = &pdev->dev;
 
 	reset->prm = prm;
 
+	sprintf(buf, "%s_clkdm", prm->data->clkdm_name ? prm->data->clkdm_name :
+		prm->data->name);
+
+	reset->clkdm = pdata->clkdm_lookup(buf);
+
 	return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
 }
 
diff --git a/include/linux/platform_data/ti-prm.h b/include/linux/platform_data/ti-prm.h
new file mode 100644
index 0000000..28154c3
--- /dev/null
+++ b/include/linux/platform_data/ti-prm.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * TI PRM (Power & Reset Manager) platform data
+ *
+ * Copyright (C) 2019 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo@xxxxxx>
+ */
+
+#ifndef _LINUX_PLATFORM_DATA_TI_PRM_H
+#define _LINUX_PLATFORM_DATA_TI_PRM_H
+
+struct clockdomain;
+
+struct ti_prm_platform_data {
+	void (*clkdm_deny_idle)(struct clockdomain *clkdm);
+	void (*clkdm_allow_idle)(struct clockdomain *clkdm);
+	struct clockdomain * (*clkdm_lookup)(const char *name);
+};
+
+#endif /* _LINUX_PLATFORM_DATA_TI_PRM_H */
-- 
1.9.1

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