linux-kernel - [PATCH v2 1/4] clk: qcom: gdsc: Add support to enable retention of GSDCR

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Date:   Sun, 17 May 2020 14:52:21 +0530
From:   Taniya Das <tdas@...eaurora.org>
To:     Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette   <mturquette@...libre.com>
Cc:     David Brown <david.brown@...aro.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andy Gross <agross@...nel.org>, devicetree@...r.kernel.org,
        robh@...nel.org, robh+dt@...nel.org,
        Taniya Das <tdas@...eaurora.org>
Subject: [PATCH v2 1/4] clk: qcom: gdsc: Add support to enable retention of GSDCR

Add support for the RETAIN_FF_ENABLE feature which enables the
usage of retention registers. These registers maintain their
state after disabling and re-enabling a GDSC.

Signed-off-by: Taniya Das <tdas@...eaurora.org>
---
 drivers/clk/qcom/gdsc.c | 12 ++++++++++++
 drivers/clk/qcom/gdsc.h |  1 +
 2 files changed, 13 insertions(+)

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index a250f59..9983456 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -28,6 +28,7 @@
 /* CFG_GDSCR */
 #define GDSC_POWER_UP_COMPLETE		BIT(16)
 #define GDSC_POWER_DOWN_COMPLETE	BIT(15)
+#define GDSC_RETAIN_FF_ENABLE		BIT(11)
 #define CFG_GDSCR_OFFSET		0x4

 /* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
@@ -202,6 +203,14 @@ static inline void gdsc_assert_reset_aon(struct gdsc *sc)
 	regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
 			   GMEM_RESET_MASK, 0);
 }
+
+static void gdsc_retain_ff_on(struct gdsc *sc)
+{
+	u32 mask = GDSC_RETAIN_FF_ENABLE;
+
+	regmap_update_bits(sc->regmap, sc->gdscr, mask, mask);
+}
+
 static int gdsc_enable(struct generic_pm_domain *domain)
 {
 	struct gdsc *sc = domain_to_gdsc(domain);
@@ -254,6 +263,9 @@ static int gdsc_enable(struct generic_pm_domain *domain)
 		udelay(1);
 	}

+	if (sc->flags & RETAIN_FF_ENABLE)
+		gdsc_retain_ff_on(sc);
+
 	return 0;
 }

diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 64cdc8c..8604d44 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -49,6 +49,7 @@ struct gdsc {
 #define AON_RESET	BIT(4)
 #define POLL_CFG_GDSCR	BIT(5)
 #define ALWAYS_ON	BIT(6)
+#define RETAIN_FF_ENABLE	BIT(7)
 	struct reset_controller_dev	*rcdev;
 	unsigned int			*resets;
 	unsigned int			reset_count;
--
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