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From: Vaibhav Gupta <vaibhavgupta40@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Vaibhav Gupta <vaibhav.varodek@gmail.com>,
	Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>,
	Tomoya MORINAGA <tomoya.rohm@gmail.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Ben Dooks <ben.dooks@codethink.co.uk>
Cc: linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-i2c@vger.kernel.org,
	Vaibhav Gupta <vaibhavgupta40@gmail.com>
Subject: [Linux-kernel-mentees] [PATCH v2 2/2] i2c: eg20t: use generic power management
Date: Thu,  6 Aug 2020 01:06:16 +0530	[thread overview]
Message-ID: <20200805193616.384313-3-vaibhavgupta40@gmail.com> (raw)
In-Reply-To: <20200805193616.384313-1-vaibhavgupta40@gmail.com>

Drivers using legacy power management .suspen()/.resume() callbacks
have to manage PCI states and device's PM states themselves. They also
need to take care of standard configuration registers.

Switch to generic power management framework using a single
"struct dev_pm_ops" variable to take the unnecessary load from the driver.
This also avoids the need for the driver to directly call most of the PCI
helper functions and device power state control functions, as through
the generic framework PCI Core takes care of the necessary operations,
and drivers are required to do only device-specific jobs.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/i2c/busses/i2c-eg20t.c | 36 +++++++---------------------------
 1 file changed, 7 insertions(+), 29 deletions(-)

diff --git a/drivers/i2c/busses/i2c-eg20t.c b/drivers/i2c/busses/i2c-eg20t.c
index eb41de22d461..843b31a0f752 100644
--- a/drivers/i2c/busses/i2c-eg20t.c
+++ b/drivers/i2c/busses/i2c-eg20t.c
@@ -846,11 +846,10 @@ static void pch_i2c_remove(struct pci_dev *pdev)
 	kfree(adap_info);
 }
 
-#ifdef CONFIG_PM
-static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused pch_i2c_suspend(struct device *dev)
 {
-	int ret;
 	int i;
+	struct pci_dev *pdev = to_pci_dev(dev);
 	struct adapter_info *adap_info = pci_get_drvdata(pdev);
 	void __iomem *p = adap_info->pch_data[0].pch_base_address;
 
@@ -872,31 +871,13 @@ static int pch_i2c_suspend(struct pci_dev *pdev, pm_message_t state)
 		ioread32(p + PCH_I2CSR), ioread32(p + PCH_I2CBUFSTA),
 		ioread32(p + PCH_I2CESRSTA));
 
-	ret = pci_save_state(pdev);
-
-	if (ret) {
-		pch_pci_err(pdev, "pci_save_state\n");
-		return ret;
-	}
-
-	pci_disable_device(pdev);
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
-
 	return 0;
 }
 
-static int pch_i2c_resume(struct pci_dev *pdev)
+static int __maybe_unused pch_i2c_resume(struct device *dev)
 {
 	int i;
-	struct adapter_info *adap_info = pci_get_drvdata(pdev);
-
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-
-	if (pci_enable_device(pdev) < 0) {
-		pch_pci_err(pdev, "pch_i2c_resume:pci_enable_device FAILED\n");
-		return -EIO;
-	}
+	struct adapter_info *adap_info = dev_get_drvdata(dev);
 
 	for (i = 0; i < adap_info->ch_num; i++)
 		pch_i2c_init(&adap_info->pch_data[i]);
@@ -905,18 +886,15 @@ static int pch_i2c_resume(struct pci_dev *pdev)
 
 	return 0;
 }
-#else
-#define pch_i2c_suspend NULL
-#define pch_i2c_resume NULL
-#endif
+
+static SIMPLE_DEV_PM_OPS(pch_i2c_pm_ops, pch_i2c_suspend, pch_i2c_resume);
 
 static struct pci_driver pch_pcidriver = {
 	.name = KBUILD_MODNAME,
 	.id_table = pch_pcidev_id,
 	.probe = pch_i2c_probe,
 	.remove = pch_i2c_remove,
-	.suspend = pch_i2c_suspend,
-	.resume = pch_i2c_resume
+	.driver.pm = &pch_i2c_pm_ops,
 };
 
 module_pci_driver(pch_pcidriver);
-- 
2.27.0

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  parent reply	other threads:[~2020-08-05 19:39 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-20 14:00 [Linux-kernel-mentees] [PATCH v1] i2c: eg20t: use generic power management Vaibhav Gupta
2020-08-05  9:16 ` Wolfram Sang
2020-08-05 15:23 ` Bjorn Helgaas
2020-08-05 15:28   ` Bjorn Helgaas
2020-08-05 16:21     ` Vaibhav Gupta
2020-08-05 16:56       ` Bjorn Helgaas
2020-08-05 17:19         ` Vaibhav Gupta
2020-08-05 19:36         ` [Linux-kernel-mentees] [PATCH v2 0/2] i2c: eg20t: Power management upgrade and clean-ups Vaibhav Gupta
2020-08-05 19:36           ` [Linux-kernel-mentees] [PATCH v2 1/2] i2c: eg20t: Drop PCI wakeup calls from .suspend/.resume Vaibhav Gupta
2020-08-10 14:01             ` Wolfram Sang
2020-08-05 19:36           ` Vaibhav Gupta [this message]
2020-08-07 20:23             ` [Linux-kernel-mentees] [PATCH v2 2/2] i2c: eg20t: use generic power management Bjorn Helgaas
2020-08-10  9:18               ` Vaibhav Gupta
2020-08-25  9:53               ` Jean Delvare
2020-08-25 15:16                 ` Bjorn Helgaas
2020-08-10 14:01             ` Wolfram Sang

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