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From: Dong Aisheng <aisheng.dong@nxp.com>
To: linux-clk@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org, sboyd@kernel.org,
	mturquette@baylibre.com, shawnguo@kernel.org,
	fabio.estevam@nxp.com, linux-imx@nxp.com, kernel@pengutronix.de,
	Dong Aisheng <aisheng.dong@nxp.com>
Subject: [PATCH V5 11/11] clk: imx: lpcg: add suspend/resume support
Date: Mon,  9 Sep 2019 22:10:08 -0400
Message-ID: <1568081408-26800-12-git-send-email-aisheng.dong@nxp.com> (raw)
In-Reply-To: <1568081408-26800-1-git-send-email-aisheng.dong@nxp.com>

LPCG clock state may be lost when it's power domain is completely
off during system suspend/resume and we need save and restore the
state properly.

Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
---
ChangeLog:
v5:
 * make suspend/resume function static
 * improve code comments
v4: no changes
v3: new patch
---
 drivers/clk/imx/clk-imx8qxp-lpcg.c |  1 +
 drivers/clk/imx/clk-lpcg-scu.c     | 37 +++++++++++++++++++++++++++++++++++++
 drivers/clk/imx/clk-scu.h          |  1 +
 3 files changed, 39 insertions(+)

diff --git a/drivers/clk/imx/clk-imx8qxp-lpcg.c b/drivers/clk/imx/clk-imx8qxp-lpcg.c
index f395eb5..99a5f55 100644
--- a/drivers/clk/imx/clk-imx8qxp-lpcg.c
+++ b/drivers/clk/imx/clk-imx8qxp-lpcg.c
@@ -338,6 +338,7 @@ static struct platform_driver imx8qxp_lpcg_clk_driver = {
 	.driver = {
 		.name = "imx8qxp-lpcg-clk",
 		.of_match_table = imx8qxp_lpcg_match,
+		.pm = &imx_clk_lpcg_scu_pm_ops,
 		.suppress_bind_attrs = true,
 	},
 	.probe = imx8qxp_lpcg_clk_probe,
diff --git a/drivers/clk/imx/clk-lpcg-scu.c b/drivers/clk/imx/clk-lpcg-scu.c
index 3c092a0..1dd928a 100644
--- a/drivers/clk/imx/clk-lpcg-scu.c
+++ b/drivers/clk/imx/clk-lpcg-scu.c
@@ -33,6 +33,9 @@ struct clk_lpcg_scu {
 	void __iomem *reg;
 	u8 bit_idx;
 	bool hw_gate;
+
+	/* for state save&restore */
+	u32 state;
 };
 
 #define to_clk_lpcg_scu(_hw) container_of(_hw, struct clk_lpcg_scu, hw)
@@ -112,5 +115,39 @@ struct clk_hw *__imx_clk_lpcg_scu(struct device *dev, const char *name,
 		hw = ERR_PTR(ret);
 	}
 
+	if (dev)
+		dev_set_drvdata(dev, clk);
+
 	return hw;
 }
+
+static int __maybe_unused imx_clk_lpcg_scu_suspend(struct device *dev)
+{
+	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
+
+	clk->state = readl_relaxed(clk->reg);
+	dev_dbg(dev, "save lpcg state 0x%x\n", clk->state);
+
+	return 0;
+}
+
+static int __maybe_unused imx_clk_lpcg_scu_resume(struct device *dev)
+{
+	struct clk_lpcg_scu *clk = dev_get_drvdata(dev);
+
+	/*
+	 * FIXME: Sometimes writes don't work unless the CPU issues
+	 * them twice
+	 */
+
+	writel(clk->state, clk->reg);
+	writel(clk->state, clk->reg);
+	dev_dbg(dev, "restore lpcg state 0x%x\n", clk->state);
+
+	return 0;
+}
+
+const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_clk_lpcg_scu_suspend,
+				      imx_clk_lpcg_scu_resume)
+};
diff --git a/drivers/clk/imx/clk-scu.h b/drivers/clk/imx/clk-scu.h
index 84efda3..6d4b6e2 100644
--- a/drivers/clk/imx/clk-scu.h
+++ b/drivers/clk/imx/clk-scu.h
@@ -12,6 +12,7 @@
 
 extern u32 clock_cells;
 extern struct list_head imx_scu_clks[];
+extern const struct dev_pm_ops imx_clk_lpcg_scu_pm_ops;
 
 int imx_clk_scu_init(struct device_node *np);
 struct clk_hw *imx_scu_of_clk_src_get(struct of_phandle_args *clkspec,
-- 
2.7.4


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10  2:09 [PATCH V5 00/11] clk: imx8: add new clock binding for better pm support Dong Aisheng
2019-09-09 14:19 ` Aisheng Dong
2019-09-10  2:09 ` [PATCH V5 01/11] dt-bindings: firmware: imx-scu: new binding to parse clocks from device tree Dong Aisheng
2019-09-10  2:09 ` [PATCH V5 02/11] dt-bindings: clock: imx-lpcg: add support " Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 03/11] clk: imx: scu: add two cells binding support Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 04/11] clk: imx: scu: bypass cpu power domains Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 05/11] clk: imx: scu: allow scu clk to take device pointer Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 06/11] clk: imx: scu: add runtime pm support Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 07/11] clk: imx: scu: add suspend/resume support Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 08/11] clk: imx: imx8qxp-lpcg: add parsing clocks from device tree Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 09/11] clk: imx: lpcg: allow lpcg clk to take device pointer Dong Aisheng
2019-09-10  2:10 ` [PATCH V5 10/11] clk: imx: clk-imx8qxp-lpcg: add runtime pm support Dong Aisheng
2019-09-10  2:10 ` Dong Aisheng [this message]
2019-09-18  6:08 ` [PATCH V5 00/11] clk: imx8: add new clock binding for better " Stephen Boyd

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