Add support for reading and configuring the OPP table in the GENI I2C
driver. This enables setting the frequency based on device tree data,
removing dependency on bootloader configuration.

Signed-off-by: Manikanta Mylavarapu <quic_mmanikan@quicinc.com>
---
v3: Fix the format-specifier to correctly display the clock rate and change
   '&pdev->dev' to 'dev' as per suggestions from Andi Shyti.
 
drivers/i2c/busses/i2c-qcom-geni.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
index ff2289b52c84..380581a3699c 100644
--- a/drivers/i2c/busses/i2c-qcom-geni.c
+++ b/drivers/i2c/busses/i2c-qcom-geni.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/pm_opp.h>
 #include <linux/pm_runtime.h>
 #include <linux/soc/qcom/geni-se.h>
 #include <linux/spinlock.h>
@@ -779,11 +780,13 @@ static int setup_gpi_dma(struct geni_i2c_dev *gi2c)
 
 static int geni_i2c_probe(struct platform_device *pdev)
 {
-	struct geni_i2c_dev *gi2c;
+	const struct geni_i2c_desc *desc = NULL;
 	u32 proto, tx_depth, fifo_disable;
-	int ret;
 	struct device *dev = &pdev->dev;
-	const struct geni_i2c_desc *desc = NULL;
+	unsigned long freq = ULONG_MAX;
+	struct geni_i2c_dev *gi2c;
+	struct dev_pm_opp *opp;
+	int ret;
 
 	gi2c = devm_kzalloc(dev, sizeof(*gi2c), GFP_KERNEL);
 	if (!gi2c)
@@ -814,6 +817,24 @@ static int geni_i2c_probe(struct platform_device *pdev)
 		gi2c->clk_freq_out = I2C_MAX_STANDARD_MODE_FREQ;
 	}
 
+	ret = devm_pm_opp_set_clkname(dev, "se");
+	if (ret)
+		return ret;
+
+	/* OPP table is optional */
+	ret = devm_pm_opp_of_add_table(dev);
+	if (!ret) {
+		opp = dev_pm_opp_find_freq_floor(dev, &freq);
+		if (IS_ERR(opp))
+			return dev_err_probe(dev, PTR_ERR(opp), "failed to find the frequency\n");
+		dev_pm_opp_put(opp);
+		ret = dev_pm_opp_set_rate(dev, freq);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to set the rate=%lu\n", freq);
+	} else if (ret && ret != -ENODEV) {
+		return dev_err_probe(dev, ret, "invalid OPP table in device tree\n");
+	}
+
 	if (has_acpi_companion(dev))
 		ACPI_COMPANION_SET(&gi2c->adap.dev, ACPI_COMPANION(dev));
 
-- 
2.34.1