counter: ti-eqep: enable clock at probe

The TI eQEP clock is both a functional and interface clock. Since it is
required for the device to function, we should be enabling it at probe.

Up to now, we've just been lucky that the clock was enabled by something
else on the system already.

Fixes: f213729 ("counter: new TI eQEP driver")
Reviewed-by: Judith Mendez <jm@ti.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240621-ti-eqep-enable-clock-v2-1-edd3421b54d4@baylibre.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

drivers/counter/ti-eqep.c

@@ -6,6 +6,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/clk.h>
 #include <linux/counter.h>
 #include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
@@ -376,6 +377,7 @@ static int ti_eqep_probe(struct platform_device *pdev)
 	struct counter_device *counter;
 	struct ti_eqep_cnt *priv;
 	void __iomem *base;
+	struct clk *clk;
 	int err;
 
 	counter = devm_counter_alloc(dev, sizeof(*priv));
@@ -415,6 +417,10 @@ static int ti_eqep_probe(struct platform_device *pdev)
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
+	clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk), "failed to enable clock\n");
+
 	err = counter_add(counter);
 	if (err < 0) {
 		pm_runtime_put_sync(dev);