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From:   Vaibhav Gupta <vaibhavgupta40@gmail.com>
To:     Bjorn Helgaas <helgaas@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Bjorn Helgaas <bjorn@helgaas.com>,
        Vaibhav Gupta <vaibhav.varodek@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>
Cc:     Vaibhav Gupta <vaibhavgupta40@gmail.com>,
        linux-serial@vger.kernel.org,
        Shuah Khan <skhan@linuxfoundation.org>,
        linux-kernel@vger.kernel.org,
        linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH v1] serial: pch_uart: use generic power management
Date:   Mon, 20 Jul 2020 17:34:15 +0530
Message-Id: <20200720120414.399961-1-vaibhavgupta40@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Drivers using legacy PM have to manage PCI states and device's PM states
themselves. They also need to take care of configuration registers.

With improved and powerful support of generic PM, PCI Core takes care of
above mentioned, device-independent, jobs.

This driver makes use of PCI helper functions like
pci_save/restore_state(), pci_enable_device() and pci_set_power_state()
to do required operations. In generic mode, they are no longer needed.

Change function parameter in both .suspend() and .resume() to
"struct device*" type. Use dev_get_drvdata() to get drv data.

Compile-tested only.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/tty/serial/pch_uart.c | 34 ++++++++++------------------------
 1 file changed, 10 insertions(+), 24 deletions(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 40fa7a27722d..67aca8cb9cd4 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1857,41 +1857,24 @@ static void pch_uart_pci_remove(struct pci_dev *pdev)
 	kfree(priv);
 	return;
 }
-#ifdef CONFIG_PM
-static int pch_uart_pci_suspend(struct pci_dev *pdev, pm_message_t state)
+
+static int __maybe_unused pch_uart_pci_suspend(struct device *dev)
 {
-	struct eg20t_port *priv = pci_get_drvdata(pdev);
+	struct eg20t_port *priv = dev_get_drvdata(dev);
 
 	uart_suspend_port(&pch_uart_driver, &priv->port);
 
-	pci_save_state(pdev);
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
 	return 0;
 }
 
-static int pch_uart_pci_resume(struct pci_dev *pdev)
+static int __maybe_unused pch_uart_pci_resume(struct device *dev)
 {
-	struct eg20t_port *priv = pci_get_drvdata(pdev);
-	int ret;
-
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-
-	ret = pci_enable_device(pdev);
-	if (ret) {
-		dev_err(&pdev->dev,
-		"%s-pci_enable_device failed(ret=%d) ", __func__, ret);
-		return ret;
-	}
+	struct eg20t_port *priv = dev_get_drvdata(dev);
 
 	uart_resume_port(&pch_uart_driver, &priv->port);
 
 	return 0;
 }
-#else
-#define pch_uart_pci_suspend NULL
-#define pch_uart_pci_resume NULL
-#endif
 
 static const struct pci_device_id pch_uart_pci_id[] = {
 	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8811),
@@ -1945,13 +1928,16 @@ static int pch_uart_pci_probe(struct pci_dev *pdev,
 	return ret;
 }
 
+static SIMPLE_DEV_PM_OPS(pch_uart_pci_pm_ops,
+			 pch_uart_pci_suspend,
+			 pch_uart_pci_resume);
+
 static struct pci_driver pch_uart_pci_driver = {
 	.name = "pch_uart",
 	.id_table = pch_uart_pci_id,
 	.probe = pch_uart_pci_probe,
 	.remove = pch_uart_pci_remove,
-	.suspend = pch_uart_pci_suspend,
-	.resume = pch_uart_pci_resume,
+	.driver.pm = &pch_uart_pci_pm_ops,
 };
 
 static int __init pch_uart_module_init(void)
-- 
2.27.0