i2c: qcom-geni: Isolate serial engine setup

Moving the serial engine setup to geni_i2c_init() API for a cleaner
probe function and utilizes the PM runtime API to control resources
instead of direct clock-related APIs for better resource management.

Enables reusability of the serial engine initialization like
hibernation and deep sleep features where hardware context is lost.

Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
Acked-by: Viken Dadhaniya <viken.dadhaniya@oss.qualcomm.com>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Reviewed-by: Mukesh Kumar Savaliya <mukesh.savaliya@oss.qualcomm.com>
Tested-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260617-enable-i2c-on-sa8255p-v7-2-ad736dbeab57@oss.qualcomm.com

drivers/i2c/busses/i2c-qcom-geni.c

@@ -990,10 +990,77 @@ static int setup_gpi_dma(struct geni_i2c_dev *gi2c)
 	return ret;
 }
 
+static int geni_i2c_init(struct geni_i2c_dev *gi2c)
+{
+	const struct geni_i2c_desc *desc = NULL;
+	u32 proto, tx_depth;
+	bool fifo_disable;
+	int ret;
+
+	ret = pm_runtime_resume_and_get(gi2c->se.dev);
+	if (ret < 0) {
+		dev_err(gi2c->se.dev, "error turning on device :%d\n", ret);
+		return ret;
+	}
+
+	proto = geni_se_read_proto(&gi2c->se);
+	if (proto == GENI_SE_INVALID_PROTO) {
+		ret = geni_load_se_firmware(&gi2c->se, GENI_SE_I2C);
+		if (ret) {
+			dev_err_probe(gi2c->se.dev, ret, "i2c firmware load failed ret: %d\n", ret);
+			goto err;
+		}
+	} else if (proto != GENI_SE_I2C) {
+		ret = dev_err_probe(gi2c->se.dev, -ENXIO, "Invalid proto %d\n", proto);
+		goto err;
+	}
+
+	desc = device_get_match_data(gi2c->se.dev);
+	if (desc && desc->no_dma_support) {
+		fifo_disable = false;
+		gi2c->no_dma = true;
+	} else {
+		fifo_disable = readl_relaxed(gi2c->se.base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
+	}
+
+	if (fifo_disable) {
+		/* FIFO is disabled, so we can only use GPI DMA */
+		gi2c->gpi_mode = true;
+		ret = setup_gpi_dma(gi2c);
+		if (ret)
+			goto err;
+
+		dev_dbg(gi2c->se.dev, "Using GPI DMA mode for I2C\n");
+	} else {
+		gi2c->gpi_mode = false;
+		tx_depth = geni_se_get_tx_fifo_depth(&gi2c->se);
+
+		/* I2C Master Hub Serial Elements doesn't have the HW_PARAM_0 register */
+		if (!tx_depth && desc)
+			tx_depth = desc->tx_fifo_depth;
+
+		if (!tx_depth) {
+			ret = dev_err_probe(gi2c->se.dev, -EINVAL,
+					    "Invalid TX FIFO depth\n");
+			goto err;
+		}
+
+		gi2c->tx_wm = tx_depth - 1;
+		geni_se_init(&gi2c->se, gi2c->tx_wm, tx_depth);
+		geni_se_config_packing(&gi2c->se, BITS_PER_BYTE,
+				       PACKING_BYTES_PW, true, true, true);
+
+		dev_dbg(gi2c->se.dev, "i2c fifo/se-dma mode. fifo depth:%d\n", tx_depth);
+	}
+
+err:
+	pm_runtime_put(gi2c->se.dev);
+	return ret;
+}
+
 static int geni_i2c_probe(struct platform_device *pdev)
 {
 	struct geni_i2c_dev *gi2c;
-	u32 proto, tx_depth, fifo_disable;
 	int ret;
 	struct device *dev = &pdev->dev;
 	const struct geni_i2c_desc *desc = NULL;
@@ -1073,101 +1140,26 @@ static int geni_i2c_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	ret = clk_prepare_enable(gi2c->core_clk);
-	if (ret)
-		return ret;
-
-	ret = geni_se_resources_on(&gi2c->se);
-	if (ret) {
-		dev_err_probe(dev, ret, "Error turning on resources\n");
-		goto err_clk;
-	}
-	proto = geni_se_read_proto(&gi2c->se);
-	if (proto == GENI_SE_INVALID_PROTO) {
-		ret = geni_load_se_firmware(&gi2c->se, GENI_SE_I2C);
-		if (ret) {
-			dev_err_probe(dev, ret, "i2c firmware load failed ret: %d\n", ret);
-			goto err_resources;
-		}
-	} else if (proto != GENI_SE_I2C) {
-		ret = dev_err_probe(dev, -ENXIO, "Invalid proto %d\n", proto);
-		goto err_resources;
-	}
-
-	if (desc && desc->no_dma_support) {
-		fifo_disable = false;
-		gi2c->no_dma = true;
-	} else {
-		fifo_disable = readl_relaxed(gi2c->se.base + GENI_IF_DISABLE_RO) & FIFO_IF_DISABLE;
-	}
-
-	if (fifo_disable) {
-		/* FIFO is disabled, so we can only use GPI DMA */
-		gi2c->gpi_mode = true;
-		ret = setup_gpi_dma(gi2c);
-		if (ret)
-			goto err_resources;
-
-		dev_dbg(dev, "Using GPI DMA mode for I2C\n");
-	} else {
-		gi2c->gpi_mode = false;
-		tx_depth = geni_se_get_tx_fifo_depth(&gi2c->se);
-
-		/* I2C Master Hub Serial Elements doesn't have the HW_PARAM_0 register */
-		if (!tx_depth && desc)
-			tx_depth = desc->tx_fifo_depth;
-
-		if (!tx_depth) {
-			ret = dev_err_probe(dev, -EINVAL,
-					    "Invalid TX FIFO depth\n");
-			goto err_resources;
-		}
-
-		gi2c->tx_wm = tx_depth - 1;
-		geni_se_init(&gi2c->se, gi2c->tx_wm, tx_depth);
-		geni_se_config_packing(&gi2c->se, BITS_PER_BYTE,
-				       PACKING_BYTES_PW, true, true, true);
-
-		dev_dbg(dev, "i2c fifo/se-dma mode. fifo depth:%d\n", tx_depth);
-	}
-
-	clk_disable_unprepare(gi2c->core_clk);
-	ret = geni_se_resources_off(&gi2c->se);
-	if (ret) {
-		dev_err_probe(dev, ret, "Error turning off resources\n");
-		goto err_dma;
-	}
-
-	ret = geni_icc_disable(&gi2c->se);
-	if (ret)
-		goto err_dma;
-
 	pm_runtime_set_suspended(gi2c->se.dev);
 	pm_runtime_set_autosuspend_delay(gi2c->se.dev, I2C_AUTO_SUSPEND_DELAY);
 	pm_runtime_use_autosuspend(gi2c->se.dev);
 	pm_runtime_enable(gi2c->se.dev);
 
+	ret = geni_i2c_init(gi2c);
+	if (ret < 0) {
+		pm_runtime_disable(gi2c->se.dev);
+		return ret;
+	}
+
 	ret = i2c_add_adapter(&gi2c->adap);
 	if (ret) {
 		dev_err_probe(dev, ret, "Error adding i2c adapter\n");
 		pm_runtime_disable(gi2c->se.dev);
-		goto err_dma;
+		return ret;
 	}
 
 	dev_dbg(dev, "Geni-I2C adaptor successfully added\n");
 
-	return ret;
-
-err_resources:
-	geni_se_resources_off(&gi2c->se);
-err_clk:
-	clk_disable_unprepare(gi2c->core_clk);
-
-	return ret;
-
-err_dma:
-	release_gpi_dma(gi2c);
-
 	return ret;
 }