mtd: st_spi_fsm: Obtain and use EMI clock

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=69d5af8d016c803420258a476789ec6e7e7844dc
Commit:     69d5af8d016c803420258a476789ec6e7e7844dc
Parent:     5ecd3ea188fd60e5f663a956dbe23d61a99f504a
Author:     Lee Jones <lee.jones at linaro.org>
AuthorDate: Mon Dec 15 11:59:09 2014 +0000
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Mon Jan 12 21:08:04 2015 -0800

    mtd: st_spi_fsm: Obtain and use EMI clock
    
    ST's Common Clk Framework is now available. This patch ensures the FSM
    makes use of it by obtaining and enabling the EMI clock. If system fails
    to provide the EMI clock, we bomb out.
    
    Signed-off-by: Lee Jones <lee.jones at linaro.org>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/devices/st_spi_fsm.c | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index bebc8b5..3451864 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -24,6 +24,7 @@
 #include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/clk.h>
 
 #include "serial_flash_cmds.h"
 
@@ -262,6 +263,7 @@ struct stfsm {
 	struct mtd_info		mtd;
 	struct mutex		lock;
 	struct flash_info       *info;
+	struct clk              *clk;
 
 	uint32_t                configuration;
 	uint32_t                fifo_dir_delay;
@@ -1906,8 +1908,7 @@ static void stfsm_set_freq(struct stfsm *fsm, uint32_t spi_freq)
 	uint32_t emi_freq;
 	uint32_t clk_div;
 
-	/* TODO: Make this dynamic */
-	emi_freq = STFSM_DEFAULT_EMI_FREQ;
+	emi_freq = clk_get_rate(fsm->clk);
 
 	/*
 	 * Calculate clk_div - values between 2 and 128
@@ -2057,6 +2058,18 @@ static int stfsm_probe(struct platform_device *pdev)
 		return PTR_ERR(fsm->base);
 	}
 
+	fsm->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(fsm->clk)) {
+		dev_err(fsm->dev, "Couldn't find EMI clock.\n");
+		return PTR_ERR(fsm->clk);
+	}
+
+	ret = clk_prepare_enable(fsm->clk);
+	if (ret) {
+		dev_err(fsm->dev, "Failed to enable EMI clock.\n");
+		return ret;
+	}
+
 	mutex_init(&fsm->lock);
 
 	ret = stfsm_init(fsm);
@@ -2121,6 +2134,28 @@ static int stfsm_remove(struct platform_device *pdev)
 	return mtd_device_unregister(&fsm->mtd);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int stfsmfsm_suspend(struct device *dev)
+{
+	struct stfsm *fsm = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(fsm->clk);
+
+	return 0;
+}
+
+static int stfsmfsm_resume(struct device *dev)
+{
+	struct stfsm *fsm = dev_get_drvdata(dev);
+
+	clk_prepare_enable(fsm->clk);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(stfsm_pm_ops, stfsmfsm_suspend, stfsmfsm_resume);
+
 static const struct of_device_id stfsm_match[] = {
 	{ .compatible = "st,spi-fsm", },
 	{},
@@ -2133,6 +2168,7 @@ static struct platform_driver stfsm_driver = {
 	.driver		= {
 		.name	= "st-spi-fsm",
 		.of_match_table = stfsm_match,
+		.pm     = &stfsm_pm_ops,
 	},
 };
 module_platform_driver(stfsm_driver);