From: Franklin S Cooper Jr <fcoo...@ti.com>

Add support for CONFIG_PM which is the new way to handle managing clocks.

Move the clock management to pm_runtime_resume() and pm_runtime_suspend()
callbacks for the driver.

CONFIG_PM is required by OMAP based devices to handle clock management.
Therefore, this allows future Texas Instruments SoCs that have the MCAN IP
to work with this driver.

Reviewed-by: Suman Anna <s-a...@ti.com>
Signed-off-by: Franklin S Cooper Jr <fcoo...@ti.com>
[nsek...@ti.com: handle pm_runtime_get_sync() failure, fix some bugs]
Signed-off-by: Sekhar Nori <nsek...@ti.com>
Signed-off-by: Faiz Abbas <faiz_ab...@ti.com>
---
 drivers/net/can/m_can/m_can.c | 95 ++++++++++++++++++++++++++++---------------
 1 file changed, 62 insertions(+), 33 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 07ebe7f..f5c5028 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/iopoll.h>
 #include <linux/can/dev.h>
 
@@ -625,21 +626,16 @@ static int m_can_clk_start(struct m_can_priv *priv)
 {
        int err;
 
-       err = clk_prepare_enable(priv->hclk);
-       if (err)
-               return err;
-
-       err = clk_prepare_enable(priv->cclk);
+       err = pm_runtime_get_sync(priv->device);
        if (err)
-               clk_disable_unprepare(priv->hclk);
+               pm_runtime_put_noidle(priv->device);
 
        return err;
 }
 
 static void m_can_clk_stop(struct m_can_priv *priv)
 {
-       clk_disable_unprepare(priv->cclk);
-       clk_disable_unprepare(priv->hclk);
+       pm_runtime_put_sync(priv->device);
 }
 
 static int m_can_get_berr_counter(const struct net_device *dev,
@@ -1561,37 +1557,26 @@ static int m_can_plat_probe(struct platform_device 
*pdev)
                goto failed_ret;
        }
 
-       /* Enable clocks. Necessary to read Core Release in order to determine
-        * M_CAN version
-        */
-       ret = clk_prepare_enable(hclk);
-       if (ret)
-               goto disable_hclk_ret;
-
-       ret = clk_prepare_enable(cclk);
-       if (ret)
-               goto disable_cclk_ret;
-
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "m_can");
        addr = devm_ioremap_resource(&pdev->dev, res);
        irq = platform_get_irq_byname(pdev, "int0");
 
        if (IS_ERR(addr) || irq < 0) {
                ret = -EINVAL;
-               goto disable_cclk_ret;
+               goto failed_ret;
        }
 
        /* message ram could be shared */
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram");
        if (!res) {
                ret = -ENODEV;
-               goto disable_cclk_ret;
+               goto failed_ret;
        }
 
        mram_addr = devm_ioremap(&pdev->dev, res->start, resource_size(res));
        if (!mram_addr) {
                ret = -ENOMEM;
-               goto disable_cclk_ret;
+               goto failed_ret;
        }
 
        /* get message ram configuration */
@@ -1600,7 +1585,7 @@ static int m_can_plat_probe(struct platform_device *pdev)
                                         sizeof(mram_config_vals) / 4);
        if (ret) {
                dev_err(&pdev->dev, "Could not get Message RAM configuration.");
-               goto disable_cclk_ret;
+               goto failed_ret;
        }
 
        /* Get TX FIFO size
@@ -1612,13 +1597,9 @@ static int m_can_plat_probe(struct platform_device *pdev)
        dev = alloc_candev(sizeof(*priv), tx_fifo_size);
        if (!dev) {
                ret = -ENOMEM;
-               goto disable_cclk_ret;
+               goto failed_ret;
        }
 
-       ret = setup_m_can_dev(pdev, dev, addr);
-       if (ret)
-               goto disable_cclk_ret;
-
        priv = netdev_priv(dev);
        dev->irq = irq;
        priv->device = &pdev->dev;
@@ -1632,6 +1613,20 @@ static int m_can_plat_probe(struct platform_device *pdev)
        platform_set_drvdata(pdev, dev);
        SET_NETDEV_DEV(dev, &pdev->dev);
 
+       /* Enable clocks. Necessary to read Core Release in order to determine
+        * M_CAN version
+        */
+       pm_runtime_enable(&pdev->dev);
+       ret = pm_runtime_get_sync(&pdev->dev);
+       if (ret)  {
+               pm_runtime_put_noidle(&pdev->dev);
+               goto pm_runtime_fail;
+       }
+
+       ret = setup_m_can_dev(pdev, dev, addr);
+       if (ret)
+               goto pm_runtime_put;
+
        ret = register_m_can_dev(dev);
        if (ret) {
                dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
@@ -1650,14 +1645,15 @@ static int m_can_plat_probe(struct platform_device 
*pdev)
         * Stop clocks. They will be reactivated once the M_CAN device is opened
         */
 
-       goto disable_cclk_ret;
+       goto pm_runtime_put;
 
 failed_free_dev:
        free_m_can_dev(dev);
-disable_cclk_ret:
-       clk_disable_unprepare(cclk);
-disable_hclk_ret:
-       clk_disable_unprepare(hclk);
+pm_runtime_put:
+       pm_runtime_put_sync(&pdev->dev);
+pm_runtime_fail:
+       if (ret)
+               pm_runtime_disable(&pdev->dev);
 failed_ret:
        return ret;
 }
@@ -1715,6 +1711,9 @@ static int m_can_plat_remove(struct platform_device *pdev)
        struct net_device *dev = platform_get_drvdata(pdev);
 
        unregister_m_can_dev(dev);
+
+       pm_runtime_disable(&pdev->dev);
+
        platform_set_drvdata(pdev, NULL);
 
        free_m_can_dev(dev);
@@ -1722,7 +1721,37 @@ static int m_can_plat_remove(struct platform_device 
*pdev)
        return 0;
 }
 
+int m_can_runtime_suspend(struct device *dev)
+{
+       struct net_device *ndev = dev_get_drvdata(dev);
+       struct m_can_priv *priv = netdev_priv(ndev);
+
+       clk_disable_unprepare(priv->cclk);
+       clk_disable_unprepare(priv->hclk);
+
+       return 0;
+}
+
+int m_can_runtime_resume(struct device *dev)
+{
+       struct net_device *ndev = dev_get_drvdata(dev);
+       struct m_can_priv *priv = netdev_priv(ndev);
+       int err;
+
+       err = clk_prepare_enable(priv->hclk);
+       if (err)
+               return err;
+
+       err = clk_prepare_enable(priv->cclk);
+       if (err)
+               clk_disable_unprepare(priv->hclk);
+
+       return err;
+}
+
 static const struct dev_pm_ops m_can_pmops = {
+       SET_RUNTIME_PM_OPS(m_can_runtime_suspend,
+                          m_can_runtime_resume, NULL)
        SET_SYSTEM_SLEEP_PM_OPS(m_can_suspend, m_can_resume)
 };
 
-- 
2.7.4

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