[PATCH] i2c: rcar_i2c: Enable configuring SCL rise and fall times

[Adam Ford]

The Linux i2c driver supports i2c-scl-rising-time-ns,
and i2c-scl-falling-time-ns, but U-Boot uses hard-coded values
for these values.

Update the calculation by fetching them from the device tree if
present and use the previous values as the default if they are
missing.

Signed-off-by: Adam Ford <aford173 at gmail.com>

diff --git a/drivers/i2c/rcar_i2c.c b/drivers/i2c/rcar_i2c.c
index 14bb6603d5..d9ece5e3a8 100644
--- a/drivers/i2c/rcar_i2c.c
+++ b/drivers/i2c/rcar_i2c.c
@@ -64,6 +64,8 @@ enum rcar_i2c_type {
 struct rcar_i2c_priv {
 	void __iomem		*base;
 	struct clk		clk;
+	u32			fall_ns;
+	u32			rise_ns;
 	u32			intdelay;
 	u32			icccr;
 	enum rcar_i2c_type	type;
@@ -278,7 +280,7 @@ static int rcar_i2c_set_speed(struct udevice *dev, uint bus_freq_hz)
 	 *  = F[sum * ick / 1000000000]
 	 *  = F[(ick / 1000000) * sum / 1000]
 	 */
-	sum = 35 + 200 + priv->intdelay;
+	sum = priv->fall_ns + priv->rise_ns + priv->intdelay;
 	round = (ick + 500000) / 1000000 * sum;
 	round = (round + 500) / 1000;
 
@@ -323,6 +325,10 @@ static int rcar_i2c_probe(struct udevice *dev)
 	int ret;
 
 	priv->base = dev_read_addr_ptr(dev);
+	priv->rise_ns = dev_read_u32_default(dev,
+					     "i2c-scl-rising-time-ns", 200);
+	priv->fall_ns = dev_read_u32_default(dev,
+					     "i2c-scl-falling-time-ns", 35);
 	priv->intdelay = dev_read_u32_default(dev,
 					      "i2c-scl-internal-delay-ns", 5);
 	priv->type = dev_get_driver_data(dev);
-- 
2.25.1