[PATCH v2] mmc: atmel-mci: add runtime pm support

[Wenyou Yang]

Add runtime pm support to atmel mci controller.
Use runtime pm APIs to enable/disable atmel mci's clock.
Use runtime autosuspend APIs to enable auto suspend delay.

Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
---
Changes v1 -> v2:
* Adjust the APIs and invoking sequence to avoid clock unbalance issue during ->probe.
* Fix miss to invoke clk_disable_unprepare() in the error handling in ->probe.
* Remove atmci_suspend/resume and use pm_runtime_force_suspend/resume() to simplify code.

 drivers/mmc/host/atmel-mci.c |   90 +++++++++++++++++++++++++++++++-----------
 1 file changed, 67 insertions(+), 23 deletions(-)

diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 0b9ddf8..f8f2bbe 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -37,6 +37,8 @@
 
 #include <linux/atmel-mci.h>
 #include <linux/atmel_pdc.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
 
 #include <asm/cacheflush.h>
 #include <asm/io.h>
@@ -44,6 +46,8 @@
 
 #include "atmel-mci-regs.h"
 
+#define AUTOSUSPEND_DELAY	50
+
 #define ATMCI_DATA_ERROR_FLAGS	(ATMCI_DCRCE | ATMCI_DTOE | ATMCI_OVRE | ATMCI_UNRE)
 #define ATMCI_DMA_THRESHOLD	16
 
@@ -386,20 +390,19 @@ static int atmci_regs_show(struct seq_file *s, void *v)
 	if (!buf)
 		return -ENOMEM;
 
+	pm_runtime_get_sync(&host->pdev->dev);
+
 	/*
 	 * Grab a more or less consistent snapshot. Note that we're
 	 * not disabling interrupts, so IMR and SR may not be
 	 * consistent.
 	 */
-	ret = clk_prepare_enable(host->mck);
-	if (ret)
-		goto out;
-
 	spin_lock_bh(&host->lock);
 	memcpy_fromio(buf, host->regs, ATMCI_REGS_SIZE);
 	spin_unlock_bh(&host->lock);
 
-	clk_disable_unprepare(host->mck);
+	pm_runtime_mark_last_busy(&host->pdev->dev);
+	pm_runtime_put_autosuspend(&host->pdev->dev);
 
 	seq_printf(s, "MR:\t0x%08x%s%s ",
 			buf[ATMCI_MR / 4],
@@ -449,7 +452,6 @@ static int atmci_regs_show(struct seq_file *s, void *v)
 				val & ATMCI_CFG_LSYNC ? " LSYNC" : "");
 	}
 
-out:
 	kfree(buf);
 
 	return ret;
@@ -1252,6 +1254,8 @@ static void atmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	WARN_ON(slot->mrq);
 	dev_dbg(&host->pdev->dev, "MRQ: cmd %u\n", mrq->cmd->opcode);
 
+	pm_runtime_get_sync(&host->pdev->dev);
+
 	/*
 	 * We may "know" the card is gone even though there's still an
 	 * electrical connection. If so, we really need to communicate
@@ -1281,7 +1285,8 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	struct atmel_mci_slot	*slot = mmc_priv(mmc);
 	struct atmel_mci	*host = slot->host;
 	unsigned int		i;
-	bool			unprepare_clk;
+
+	pm_runtime_get_sync(&host->pdev->dev);
 
 	slot->sdc_reg &= ~ATMCI_SDCBUS_MASK;
 	switch (ios->bus_width) {
@@ -1297,13 +1302,8 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		unsigned int clock_min = ~0U;
 		u32 clkdiv;
 
-		clk_prepare(host->mck);
-		unprepare_clk = true;
-
 		spin_lock_bh(&host->lock);
 		if (!host->mode_reg) {
-			clk_enable(host->mck);
-			unprepare_clk = false;
 			atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
 			atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIEN);
 			if (host->caps.has_cfg_reg)
@@ -1371,8 +1371,6 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	} else {
 		bool any_slot_active = false;
 
-		unprepare_clk = false;
-
 		spin_lock_bh(&host->lock);
 		slot->clock = 0;
 		for (i = 0; i < ATMCI_MAX_NR_SLOTS; i++) {
@@ -1385,17 +1383,12 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 			atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIDIS);
 			if (host->mode_reg) {
 				atmci_readl(host, ATMCI_MR);
-				clk_disable(host->mck);
-				unprepare_clk = true;
 			}
 			host->mode_reg = 0;
 		}
 		spin_unlock_bh(&host->lock);
 	}
 
-	if (unprepare_clk)
-		clk_unprepare(host->mck);
-
 	switch (ios->power_mode) {
 	case MMC_POWER_OFF:
 		if (!IS_ERR(mmc->supply.vmmc))
@@ -1421,6 +1414,9 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 		 */
 		break;
 	}
+
+	pm_runtime_mark_last_busy(&host->pdev->dev);
+	pm_runtime_put_autosuspend(&host->pdev->dev);
 }
 
 static int atmci_get_ro(struct mmc_host *mmc)
@@ -1512,6 +1508,9 @@ static void atmci_request_end(struct atmel_mci *host, struct mmc_request *mrq)
 	spin_unlock(&host->lock);
 	mmc_request_done(prev_mmc, mrq);
 	spin_lock(&host->lock);
+
+	pm_runtime_mark_last_busy(&host->pdev->dev);
+	pm_runtime_put_autosuspend(&host->pdev->dev);
 }
 
 static void atmci_command_complete(struct atmel_mci *host,
@@ -2417,15 +2416,16 @@ static int __init atmci_probe(struct platform_device *pdev)
 
 	atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
 	host->bus_hz = clk_get_rate(host->mck);
-	clk_disable_unprepare(host->mck);
 
 	host->mapbase = regs->start;
 
 	tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);
 
 	ret = request_irq(irq, atmci_interrupt, 0, dev_name(&pdev->dev), host);
-	if (ret)
+	if (ret) {
+		clk_disable_unprepare(host->mck);
 		return ret;
+	}
 
 	/* Get MCI capabilities and set operations according to it */
 	atmci_get_cap(host);
@@ -2449,6 +2449,12 @@ static int __init atmci_probe(struct platform_device *pdev)
 
 	setup_timer(&host->timer, atmci_timeout_timer, (unsigned long)host);
 
+	pm_runtime_get_noresume(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
 	/* We need at least one slot to succeed */
 	nr_slots = 0;
 	ret = -ENODEV;
@@ -2491,6 +2497,9 @@ static int __init atmci_probe(struct platform_device *pdev)
 			"Atmel MCI controller at 0x%08lx irq %d, %u slots\n",
 			host->mapbase, irq, nr_slots);
 
+	pm_runtime_mark_last_busy(&host->pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+
 	return 0;
 
 err_dma_alloc:
@@ -2499,6 +2508,11 @@ err_dma_alloc:
 			atmci_cleanup_slot(host->slot[i], i);
 	}
 err_init_slot:
+	clk_disable_unprepare(host->mck);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
 	del_timer_sync(&host->timer);
 	if (host->dma.chan)
 		dma_release_channel(host->dma.chan);
@@ -2511,6 +2525,8 @@ static int __exit atmci_remove(struct platform_device *pdev)
 	struct atmel_mci	*host = platform_get_drvdata(pdev);
 	unsigned int		i;
 
+	pm_runtime_get_sync(&pdev->dev);
+
 	if (host->buffer)
 		dma_free_coherent(&pdev->dev, host->buf_size,
 		                  host->buffer, host->buf_phys_addr);
@@ -2520,11 +2536,9 @@ static int __exit atmci_remove(struct platform_device *pdev)
 			atmci_cleanup_slot(host->slot[i], i);
 	}
 
-	clk_prepare_enable(host->mck);
 	atmci_writel(host, ATMCI_IDR, ~0UL);
 	atmci_writel(host, ATMCI_CR, ATMCI_CR_MCIDIS);
 	atmci_readl(host, ATMCI_SR);
-	clk_disable_unprepare(host->mck);
 
 	del_timer_sync(&host->timer);
 	if (host->dma.chan)
@@ -2532,14 +2546,44 @@ static int __exit atmci_remove(struct platform_device *pdev)
 
 	free_irq(platform_get_irq(pdev, 0), host);
 
+	clk_disable_unprepare(host->mck);
+
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int atmci_runtime_suspend(struct device *dev)
+{
+	struct atmel_mci *host = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(host->mck);
+
 	return 0;
 }
 
+static int atmci_runtime_resume(struct device *dev)
+{
+	struct atmel_mci *host = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(host->mck);
+}
+
+static const struct dev_pm_ops atmci_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+	SET_PM_RUNTIME_PM_OPS(atmci_runtime_suspend, atmci_runtime_resume, NULL)
+};
+#endif
+
 static struct platform_driver atmci_driver = {
 	.remove		= __exit_p(atmci_remove),
 	.driver		= {
 		.name		= "atmel_mci",
 		.of_match_table	= of_match_ptr(atmci_dt_ids),
+		.pm		= &atmci_dev_pm_ops,
 	},
 };
 
-- 
1.7.9.5

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