media: atmel-isc: Add spin lock for clock enable ops

Add the spin lock for the clock enable and disable operations.
Signed-off-by: Wenyou Yang <wenyou.yang@microchip.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/atmel/atmel-isc.c

@@ -65,6 +65,7 @@ struct isc_clk {
 	struct clk_hw   hw;
 	struct clk      *clk;
 	struct regmap   *regmap;
+	spinlock_t	lock;
 	u8		id;
 	u8		parent_id;
 	u32		div;
@@ -312,26 +313,37 @@ static int isc_clk_enable(struct clk_hw *hw)
 	struct isc_clk *isc_clk = to_isc_clk(hw);
 	u32 id = isc_clk->id;
 	struct regmap *regmap = isc_clk->regmap;
+	unsigned long flags;
+	unsigned int status;
 
 	dev_dbg(isc_clk->dev, "ISC CLK: %s, div = %d, parent id = %d\n",
 		__func__, isc_clk->div, isc_clk->parent_id);
 
+	spin_lock_irqsave(&isc_clk->lock, flags);
 	regmap_update_bits(regmap, ISC_CLKCFG,
 			   ISC_CLKCFG_DIV_MASK(id) | ISC_CLKCFG_SEL_MASK(id),
 			   (isc_clk->div << ISC_CLKCFG_DIV_SHIFT(id)) |
 			   (isc_clk->parent_id << ISC_CLKCFG_SEL_SHIFT(id)));
 
 	regmap_write(regmap, ISC_CLKEN, ISC_CLK(id));
+	spin_unlock_irqrestore(&isc_clk->lock, flags);
 
-	return 0;
+	regmap_read(regmap, ISC_CLKSR, &status);
+	if (status & ISC_CLK(id))
+		return 0;
+	else
+		return -EINVAL;
 }
 
 static void isc_clk_disable(struct clk_hw *hw)
 {
 	struct isc_clk *isc_clk = to_isc_clk(hw);
 	u32 id = isc_clk->id;
+	unsigned long flags;
 
+	spin_lock_irqsave(&isc_clk->lock, flags);
 	regmap_write(isc_clk->regmap, ISC_CLKDIS, ISC_CLK(id));
+	spin_unlock_irqrestore(&isc_clk->lock, flags);
 }
 
 static int isc_clk_is_enabled(struct clk_hw *hw)
@@ -492,6 +504,7 @@ static int isc_clk_register(struct isc_device *isc, unsigned int id)
 	isc_clk->regmap		= regmap;
 	isc_clk->id		= id;
 	isc_clk->dev		= isc->dev;
+	spin_lock_init(&isc_clk->lock);
 
 	isc_clk->clk = clk_register(isc->dev, &isc_clk->hw);
 	if (IS_ERR(isc_clk->clk)) {