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From:   Taniya Das <tdas@codeaurora.org>
To:     Stephen Boyd <sboyd@kernel.org>,
        =?UTF-8?q?Michael=20Turquette=20=C2=A0?= <mturquette@baylibre.com>
Cc:     David Brown <david.brown@linaro.org>,
        Rajendra Nayak <rnayak@codeaurora.org>,
        linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        Andy Gross <agross@kernel.org>, devicetree@vger.kernel.org,
        robh@kernel.org, robh+dt@kernel.org,
        Taniya Das <tdas@codeaurora.org>
Subject: [PATCH v4 1/4] clk: qcom: gdsc: Add support to enable retention of GSDCR
Date:   Wed, 15 Jul 2020 12:06:47 +0530
Message-Id: <1594795010-9074-2-git-send-email-tdas@codeaurora.org>
In-Reply-To: <1594795010-9074-1-git-send-email-tdas@codeaurora.org>
References: <1594795010-9074-1-git-send-email-tdas@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@codeaurora.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 04944f1..2502430 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -29,6 +29,7 @@
 /* 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). */
@@ -216,6 +217,14 @@ 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);
@@ -268,6 +277,9 @@ 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 c36fc26..a5076fe 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -50,6 +50,7 @@ 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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