1 files changed, 25 insertions, 3 deletions

diff --git a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
index 66239f129a4d..65bcd1c548d2 100644
--- a/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
+++ b/drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c
@@ -713,14 +713,32 @@ static void gpmi_nfc_compute_timings(struct gpmi_nand_data *this,
 			      (use_half_period ? BM_GPMI_CTRL1_HALF_PERIOD : 0);
 }
 
-static void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
+static int gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
 {
 	struct gpmi_nfc_hardware_timing *hw = &this->hw;
 	struct resources *r = &this->resources;
 	void __iomem *gpmi_regs = r->gpmi_regs;
 	unsigned int dll_wait_time_us;
+	int ret;
+
+	/* Clock dividers do NOT guarantee a clean clock signal on its output
+	 * during the change of the divide factor on i.MX6Q/UL/SX. On i.MX7/8,
+	 * all clock dividers provide these guarantee.
+	 */
+	if (GPMI_IS_MX6Q(this) || GPMI_IS_MX6SX(this))
+		clk_disable_unprepare(r->clock[0]);
+
+	ret = clk_set_rate(r->clock[0], hw->clk_rate);
+	if (ret) {
+		dev_err(this->dev, "cannot set clock rate to %lu Hz: %d\n", hw->clk_rate, ret);
+		return ret;
+	}
 
-	clk_set_rate(r->clock[0], hw->clk_rate);
+	if (GPMI_IS_MX6Q(this) || GPMI_IS_MX6SX(this)) {
+		ret = clk_prepare_enable(r->clock[0]);
+		if (ret)
+			return ret;
+	}
 
 	writel(hw->timing0, gpmi_regs + HW_GPMI_TIMING0);
 	writel(hw->timing1, gpmi_regs + HW_GPMI_TIMING1);
@@ -739,6 +757,8 @@ static void gpmi_nfc_apply_timings(struct gpmi_nand_data *this)
 
 	/* Wait for the DLL to settle. */
 	udelay(dll_wait_time_us);
+
+	return 0;
 }
 
 static int gpmi_setup_interface(struct nand_chip *chip, int chipnr,
@@ -2269,7 +2289,9 @@ static int gpmi_nfc_exec_op(struct nand_chip *chip,
 	 */
 	if (this->hw.must_apply_timings) {
 		this->hw.must_apply_timings = false;
-		gpmi_nfc_apply_timings(this);
+		ret = gpmi_nfc_apply_timings(this);
+		if (ret)
+			return ret;
 	}
 
 	dev_dbg(this->dev, "%s: %d instructions\n", __func__, op->ninstrs);