[ARM] Tegra: SPI: Suspend/resume.

Save/restore SLINK_COMMAND_0 register.

Wait for in-progress transactions to complete before suspend.

Reject and WARN_ON transactions when suspended.

Change-Id: I0527781f0bf95781afa3a35a68282cde2f0189ae
Signed-off-by: Todd Poynor <toddpoynor@google.com>

diff --git a/drivers/spi/spi_tegra.c b/drivers/spi/spi_tegra.c
index df2fb186f0a91a2708434c056ecf8eea5b8603d0..6023da9a103a28d104860c0129c687bee33682ad 100644 (file)
--- a/drivers/spi/spi_tegra.c
+++ b/drivers/spi/spi_tegra.c
@@ -165,6 +165,8 @@ struct spi_tegra_data {
        struct tegra_dma_channel *rx_dma;
        u32                     *rx_bb;
        dma_addr_t              rx_bb_phys;
+       bool                    is_suspended;
+       unsigned long           save_slink_cmd;
 };
 
 
@@ -450,9 +452,15 @@ static int spi_tegra_transfer(struct spi_device *spi, struct spi_message *m)
                        return -EINVAL;
        }
 
+       spin_lock_irqsave(&tspi->lock, flags);
+
+       if (WARN_ON(tspi->is_suspended)) {
+               spin_unlock_irqrestore(&tspi->lock, flags);
+               return -EBUSY;
+       }
+
        m->state = spi;
 
-       spin_lock_irqsave(&tspi->lock, flags);
        was_empty = list_empty(&tspi->queue);
        list_add_tail(&m->queue, &tspi->queue);
 
@@ -600,6 +608,50 @@ static int __devexit spi_tegra_remove(struct platform_device *pdev)
        return 0;
 }
 
+#ifdef CONFIG_PM
+static int spi_tegra_suspend(struct platform_device *pdev, pm_message_t state)
+{
+       struct spi_master       *master;
+       struct spi_tegra_data   *tspi;
+       unsigned long           flags;
+       unsigned                limit = 500;
+
+       master = dev_get_drvdata(&pdev->dev);
+       tspi = spi_master_get_devdata(master);
+       spin_lock_irqsave(&tspi->lock, flags);
+       tspi->is_suspended = true;
+       WARN_ON(!list_empty(&tspi->queue));
+
+       while (!list_empty(&tspi->queue) && limit--) {
+               spin_unlock_irqrestore(&tspi->lock, flags);
+               msleep(10);
+               spin_lock_irqsave(&tspi->lock, flags);
+       }
+
+       tspi->save_slink_cmd = spi_tegra_readl(tspi, SLINK_COMMAND);
+       spin_unlock_irqrestore(&tspi->lock, flags);
+       return 0;
+}
+
+static int spi_tegra_resume(struct platform_device *pdev)
+{
+       struct spi_master       *master;
+       struct spi_tegra_data   *tspi;
+       unsigned long           flags;
+
+       master = dev_get_drvdata(&pdev->dev);
+       tspi = spi_master_get_devdata(master);
+       spin_lock_irqsave(&tspi->lock, flags);
+       clk_enable(tspi->clk);
+       spi_tegra_writel(tspi, tspi->save_slink_cmd, SLINK_COMMAND);
+       clk_disable(tspi->clk);
+       tspi->cur_speed = 0;
+       tspi->is_suspended = false;
+       spin_unlock_irqrestore(&tspi->lock, flags);
+       return 0;
+}
+#endif
+
 MODULE_ALIAS("platform:spi_tegra");
 
 static struct platform_driver spi_tegra_driver = {
@@ -608,6 +660,10 @@ static struct platform_driver spi_tegra_driver = {
                .owner =        THIS_MODULE,
        },
        .remove =       __devexit_p(spi_tegra_remove),
+#ifdef CONFIG_PM
+       .suspend =      spi_tegra_suspend,
+       .resume  =      spi_tegra_resume,
+#endif
 };
 
 static int __init spi_tegra_init(void)