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    Subject[PATCH 12/13] i2c-designware: Add runtime power management support
    Date
    From: Dirk Brandewie <dirk.brandewie@gmail.com>

    Add runtime power management to the PCI driver.

    Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
    Signed-off-by: Ben Dooks <ben-linux@fluff.org>
    ---
    drivers/i2c/busses/i2c-designware-core.c | 10 +++-
    drivers/i2c/busses/i2c-designware-core.h | 1 +
    drivers/i2c/busses/i2c-designware-pcidrv.c | 89 ++++++++++++++++++++++++++++
    3 files changed, 98 insertions(+), 2 deletions(-)

    diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
    index b9f18dd..df87992 100644
    --- a/drivers/i2c/busses/i2c-designware-core.c
    +++ b/drivers/i2c/busses/i2c-designware-core.c
    @@ -31,6 +31,7 @@
    #include <linux/i2c.h>
    #include <linux/interrupt.h>
    #include <linux/io.h>
    +#include <linux/pm_runtime.h>
    #include <linux/delay.h>
    #include "i2c-designware-core.h"

    @@ -501,6 +502,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
    dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);

    mutex_lock(&dev->lock);
    + pm_runtime_get_sync(dev->dev);

    INIT_COMPLETION(dev->cmd_complete);
    dev->msgs = msgs;
    @@ -550,6 +552,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
    ret = -EIO;

    done:
    + pm_runtime_put(dev->dev);
    mutex_unlock(&dev->lock);

    return ret;
    @@ -671,10 +674,13 @@ void i2c_dw_enable(struct dw_i2c_dev *dev)
    dw_writel(dev, 1, DW_IC_ENABLE);
    }

    -void i2c_dw_disable(struct dw_i2c_dev *dev)
    +u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev)
    {
    - int ret;
    + return dw_readl(dev, DW_IC_ENABLE);
    +}

    +void i2c_dw_disable(struct dw_i2c_dev *dev)
    +{
    /* Disable controller */
    dw_writel(dev, 0, DW_IC_ENABLE);

    diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
    index 6450a6a..4a75888 100644
    --- a/drivers/i2c/busses/i2c-designware-core.h
    +++ b/drivers/i2c/busses/i2c-designware-core.h
    @@ -98,6 +98,7 @@ extern int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
    extern u32 i2c_dw_func(struct i2c_adapter *adap);
    extern irqreturn_t i2c_dw_isr(int this_irq, void *dev_id);
    extern void i2c_dw_enable(struct dw_i2c_dev *dev);
    +extern u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev);
    extern void i2c_dw_disable(struct dw_i2c_dev *dev);
    extern void i2c_dw_clear_int(struct dw_i2c_dev *dev);
    extern void i2c_dw_disable_int(struct dw_i2c_dev *dev);
    diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
    index 83307ef..d2223b5 100644
    --- a/drivers/i2c/busses/i2c-designware-pcidrv.c
    +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
    @@ -38,6 +38,7 @@
    #include <linux/io.h>
    #include <linux/slab.h>
    #include <linux/pci.h>
    +#include <linux/pm_runtime.h>
    #include "i2c-designware-core.h"

    #define DRIVER_NAME "i2c-designware-pci"
    @@ -137,6 +138,82 @@ static struct i2c_algorithm i2c_dw_algo = {
    .functionality = i2c_dw_func,
    };

    +static int i2c_dw_pci_suspend(struct pci_dev *pdev, pm_message_t mesg)
    +{
    + struct dw_i2c_dev *i2c = pci_get_drvdata(pdev);
    + int err;
    +
    +
    + i2c_dw_disable(i2c);
    +
    + err = pci_save_state(pdev);
    + if (err) {
    + dev_err(&pdev->dev, "pci_save_state failed\n");
    + return err;
    + }
    +
    + err = pci_set_power_state(pdev, PCI_D3hot);
    + if (err) {
    + dev_err(&pdev->dev, "pci_set_power_state failed\n");
    + return err;
    + }
    +
    + return 0;
    +}
    +
    +static int i2c_dw_pci_runtime_suspend(struct device *dev)
    +{
    + struct pci_dev *pdev = to_pci_dev(dev);
    + dev_dbg(dev, "PCI suspend called\n");
    + return i2c_dw_pci_suspend(pdev, PMSG_SUSPEND);
    +}
    +
    +static int i2c_dw_pci_resume(struct pci_dev *pdev)
    +{
    + struct dw_i2c_dev *i2c = pci_get_drvdata(pdev);
    + int err;
    + u32 enabled;
    +
    + enabled = i2c_dw_is_enabled(i2c);
    + if (enabled)
    + return 0;
    +
    + err = pci_set_power_state(pdev, PCI_D0);
    + if (err) {
    + dev_err(&pdev->dev, "pci_set_power_state() failed\n");
    + return err;
    + }
    +
    + pci_restore_state(pdev);
    +
    + i2c_dw_init(i2c);
    + i2c_dw_enable(i2c);
    + return 0;
    +}
    +
    +static int i2c_dw_pci_runtime_resume(struct device *dev)
    +{
    + struct pci_dev *pdev = to_pci_dev(dev);
    + dev_dbg(dev, "runtime_resume called\n");
    + return i2c_dw_pci_resume(pdev);
    +}
    +
    +static int i2c_dw_pci_runtime_idle(struct device *dev)
    +{
    + int err = pm_schedule_suspend(dev, 500);
    + dev_dbg(dev, "runtime_idle called\n");
    +
    + if (err != 0)
    + return 0;
    + return -EBUSY;
    +}
    +
    +static const struct dev_pm_ops i2c_dw_pm_ops = {
    + .runtime_suspend = i2c_dw_pci_runtime_suspend,
    + .runtime_resume = i2c_dw_pci_runtime_resume,
    + .runtime_idle = i2c_dw_pci_runtime_idle,
    +};
    +
    static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
    {
    return dev->controller->clk_khz;
    @@ -245,6 +322,9 @@ const struct pci_device_id *id)
    goto err_free_irq;
    }

    + pm_runtime_put_noidle(&pdev->dev);
    + pm_runtime_allow(&pdev->dev);
    +
    return 0;

    err_free_irq:
    @@ -264,6 +344,10 @@ static void __devexit i2c_dw_pci_remove(struct pci_dev *pdev)
    {
    struct dw_i2c_dev *dev = pci_get_drvdata(pdev);

    + i2c_dw_disable(dev);
    + pm_runtime_forbid(&pdev->dev);
    + pm_runtime_get_noresume(&pdev->dev);
    +
    pci_set_drvdata(pdev, NULL);
    i2c_del_adapter(&dev->adapter);
    put_device(&pdev->dev);
    @@ -297,6 +381,11 @@ static struct pci_driver dw_i2c_driver = {
    .id_table = i2_designware_pci_ids,
    .probe = i2c_dw_pci_probe,
    .remove = __devexit_p(i2c_dw_pci_remove),
    + .resume = i2c_dw_pci_resume,
    + .suspend = i2c_dw_pci_suspend,
    + .driver = {
    + .pm = &i2c_dw_pm_ops,
    + },
    };

    static int __init dw_i2c_init_driver(void)
    --
    1.7.3.4


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