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From:   Ben Chuang <benchuanggli@gmail.com>
To:     adrian.hunter@intel.com, ulf.hansson@linaro.org
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
        greg.tu@genesyslogic.com.tw, ben.chuang@genesyslogic.com.tw,
        SeanHY.Chen@genesyslogic.com.tw, hl.liu@genesyslogic.com.tw,
        Ben Chuang <benchuanggli@gmail.com>,
        Kevin Chang <kevin.chang@lcfuturecenter.com>
Subject: [PATCH V2] mmc: sdhci-pci-gli: Add runtime PM for GL9763E
Date:   Mon,  7 Mar 2022 17:00:09 +0800
Message-Id: <20220307090009.1386876-1-benchuanggli@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Ben Chuang <ben.chuang@genesyslogic.com.tw>

Add runtime PM for GL9763E and disable PLL in runtime suspend. So power
gated of upstream port can be enabled. GL9763E has an auxiliary power
so it keep states in runtime suspend. In runtime resume, PLL is enabled
and waits for it to stabilize.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Tested-by: Kevin Chang <kevin.chang@lcfuturecenter.com>
---
Changes in v2:
* modify commit messages
* Use read_poll_timeout() instead of while loop
---
 drivers/mmc/host/sdhci-pci-gli.c | 47 ++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/mmc/host/sdhci-pci-gli.c b/drivers/mmc/host/sdhci-pci-gli.c
index 97035d77c18c..c854c8db32e4 100644
--- a/drivers/mmc/host/sdhci-pci-gli.c
+++ b/drivers/mmc/host/sdhci-pci-gli.c
@@ -13,6 +13,7 @@
 #include <linux/mmc/mmc.h>
 #include <linux/delay.h>
 #include <linux/of.h>
+#include <linux/iopoll.h>
 #include "sdhci.h"
 #include "sdhci-pci.h"
 #include "cqhci.h"
@@ -873,6 +874,47 @@ static void gli_set_gl9763e(struct sdhci_pci_slot *slot)
 	pci_write_config_dword(pdev, PCIE_GLI_9763E_VHS, value);
 }
 
+#ifdef CONFIG_PM
+static int gl9763e_runtime_suspend(struct sdhci_pci_chip *chip)
+{
+	struct sdhci_pci_slot *slot = chip->slots[0];
+	struct sdhci_host *host = slot->host;
+	u16 clock;
+
+	clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+	clock &= ~(SDHCI_CLOCK_PLL_EN | SDHCI_CLOCK_CARD_EN);
+	sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
+
+	return 0;
+}
+
+static int gl9763e_runtime_resume(struct sdhci_pci_chip *chip)
+{
+	struct sdhci_pci_slot *slot = chip->slots[0];
+	struct sdhci_host *host = slot->host;
+	u16 clock;
+
+	clock = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+
+	clock |= SDHCI_CLOCK_PLL_EN;
+	clock &= ~SDHCI_CLOCK_INT_STABLE;
+	sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
+
+	/* Wait max 150 ms */
+	if (read_poll_timeout(sdhci_readw, clock, (clock & SDHCI_CLOCK_INT_STABLE),
+			      1000, 150000, false, host, SDHCI_CLOCK_CONTROL)) {
+		pr_err("%s: PLL clock never stabilised.\n",
+		       mmc_hostname(host->mmc));
+		sdhci_dumpregs(host);
+	}
+
+	clock |= SDHCI_CLOCK_CARD_EN;
+	sdhci_writew(host, clock, SDHCI_CLOCK_CONTROL);
+
+	return 0;
+}
+#endif
+
 static int gli_probe_slot_gl9763e(struct sdhci_pci_slot *slot)
 {
 	struct pci_dev *pdev = slot->chip->pdev;
@@ -982,6 +1024,11 @@ const struct sdhci_pci_fixes sdhci_gl9763e = {
 #ifdef CONFIG_PM_SLEEP
 	.resume		= sdhci_cqhci_gli_resume,
 	.suspend	= sdhci_cqhci_gli_suspend,
+#endif
+#ifdef CONFIG_PM
+	.runtime_suspend = gl9763e_runtime_suspend,
+	.runtime_resume  = gl9763e_runtime_resume,
+	.allow_runtime_pm = true,
 #endif
 	.add_host       = gl9763e_add_host,
 };
-- 
2.35.1