linux-kernel - [PATCH 1/3] clk: qcom: gdsc: Add support to reset AON and block reset logic

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Message-Id: <1522665945-28147-2-git-send-email-tdas@codeaurora.org>
Date:   Mon,  2 Apr 2018 16:15:43 +0530
From:   Taniya Das <tdas@...eaurora.org>
To:     Stephen Boyd <sboyd@...eaurora.org>,
        Michael Turquette <mturquette@...libre.com>
Cc:     Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Odelu Kukatla <okukatla@...eaurora.org>,
        Amit Nischal <anischal@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Taniya Das <tdas@...eaurora.org>
Subject: [PATCH 1/3] clk: qcom: gdsc: Add support to reset AON and block reset logic

From: Amit Nischal <anischal@...eaurora.org>

For some of the gdsc power domains, there could be need to reset the
AON logic or assert/deassert the block control reset before removing
the clamp_io. Add support for the same by introducing new flags
SW_RESET and AON_RESET. Both SW reset and AON reset requires to be
asserted for at least 1us before being de-asserted.

Signed-off-by: Taniya Das <tdas@...eaurora.org>
Signed-off-by: Amit Nischal <anischal@...eaurora.org>
---
 drivers/clk/qcom/gdsc.c | 22 ++++++++++++++++++++--
 drivers/clk/qcom/gdsc.h |  4 +++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index a4f3580..266fefa 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -31,6 +31,7 @@
 #define HW_CONTROL_MASK		BIT(1)
 #define SW_COLLAPSE_MASK	BIT(0)
 #define GMEM_CLAMP_IO_MASK	BIT(0)
+#define GMEM_RESET_MASK		BIT(4)

 /* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
 #define EN_REST_WAIT_VAL	(0x2 << 20)
@@ -166,6 +167,14 @@ static inline void gdsc_assert_clamp_io(struct gdsc *sc)
 			   GMEM_CLAMP_IO_MASK, 1);
 }

+static inline void gdsc_assert_reset_aon(struct gdsc *sc)
+{
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_RESET_MASK, 1);
+	udelay(1);
+	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
+			   GMEM_RESET_MASK, 0);
+}
 static int gdsc_enable(struct generic_pm_domain *domain)
 {
 	struct gdsc *sc = domain_to_gdsc(domain);
@@ -174,8 +183,17 @@ static int gdsc_enable(struct generic_pm_domain *domain)
 	if (sc->pwrsts == PWRSTS_ON)
 		return gdsc_deassert_reset(sc);

-	if (sc->flags & CLAMP_IO)
+	if (sc->flags & SW_RESET) {
+		gdsc_assert_reset(sc);
+		udelay(1);
+		gdsc_deassert_reset(sc);
+	}
+
+	if (sc->flags & CLAMP_IO) {
+		if (sc->flags & AON_RESET)
+			gdsc_assert_reset_aon(sc);
 		gdsc_deassert_clamp_io(sc);
+	}

 	ret = gdsc_toggle_logic(sc, true);
 	if (ret)
diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 3964834..9279278 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2015, 2017-2018, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -53,6 +53,8 @@ struct gdsc {
 #define VOTABLE		BIT(0)
 #define CLAMP_IO	BIT(1)
 #define HW_CTRL		BIT(2)
+#define SW_RESET	BIT(3)
+#define AON_RESET	BIT(4)
 	struct reset_controller_dev	*rcdev;
 	unsigned int			*resets;
 	unsigned int			reset_count;
--
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