diff mbox series

[v3,01/13] PCI: imx6: Simplify clock handling by using HAS_CLK_* bitmask

Message ID 20231211215842.134823-2-Frank.Li@nxp.com
State New
Headers show
Series [v3,01/13] PCI: imx6: Simplify clock handling by using HAS_CLK_* bitmask | expand

Commit Message

Frank Li Dec. 11, 2023, 9:58 p.m. UTC 
Refactors the clock handling logic in the imx6 PCI driver by adding
HAS_CLK_* bitmask define for drvdata::flags . Simplifies the code and makes
it more maintainable, as future additions of SOC support will only require
straightforward changes. The drvdata::flags and a bitmask ensures a cleaner
and more scalable switch-case structure for handling clocks.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---

Notes:
    Change from v1 to v3
    - none

 drivers/pci/controller/dwc/pci-imx6.c | 84 +++++++++++++--------------
 1 file changed, 42 insertions(+), 42 deletions(-)

Comments

Frank Li Dec. 12, 2023, 11:18 p.m. UTC | #1 
On Tue, Dec 12, 2023 at 04:54:26PM -0600, Rob Herring wrote:
> On Tue, Dec 12, 2023 at 10:19:13PM +0530, Manivannan Sadhasivam wrote:
> > On Mon, Dec 11, 2023 at 04:58:30PM -0500, Frank Li wrote:
> > > Refactors the clock handling logic in the imx6 PCI driver by adding
> > > HAS_CLK_* bitmask define for drvdata::flags . Simplifies the code and makes
> > > it more maintainable, as future additions of SOC support will only require
> > > straightforward changes. The drvdata::flags and a bitmask ensures a cleaner
> > > and more scalable switch-case structure for handling clocks.
> > > 
> > 
> > Is there any necessity to validate each clock in the driver? I mean, can't you
> > just rely on devicetree to provide enough clocks for the functioning of the PCIe
> > controller?
> > 
> > If you can rely on devicetree (everyone should in an ideal world), then you can
> > just use devm_clk_bulk_get_all() to get all available clocks for the SoC and
> > just enable/disable whatever is available.
> 
> Or just use the *_get_optional() variants of functions. They return NULL 
> such that subsequent calls are just NOPs if the resource is not present. 
> Of course, they aren't really optional on any given platform in this 
> case, but does that really matter.

I think it'd better use devm_clk_bulk_get() by passed down a clk name list
.clk_names = {"pcie_aux", ...},

So it will not silient when dts are not matched requirement. It is not
complex because only check once at probe.

Frank

> 
> There isn't an optional variant for phys, but it can be added.
> 
> > 
> > This will greatly simplify the code.
> > 
> > Only downside of this approach is, if the devicetree is not supplying enough
> > clocks, then it will be difficult to find why PCIe is not working. But this also
> > means that the devicetree is screwed.
> 
> A sufficient schema should prevent that... That's what they're for, not 
> just torturing people to learn json-schema. :)
> 
> Rob
diff mbox series

Patch

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index 74703362aeec7..8a9b527934f80 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -60,6 +60,10 @@  enum imx6_pcie_variants {
 #define IMX6_PCIE_FLAG_IMX6_PHY			BIT(0)
 #define IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE	BIT(1)
 #define IMX6_PCIE_FLAG_SUPPORTS_SUSPEND		BIT(2)
+#define IMX6_PCIE_FLAG_HAS_CLK_INBOUND_AXI	BIT(3)
+#define IMX6_PCIE_FLAG_HAS_CLK_AUX		BIT(4)
+
+#define imx6_check_flag(pci, val)	(pci->drvdata->flags & val)
 
 struct imx6_pcie_drvdata {
 	enum imx6_pcie_variants variant;
@@ -550,19 +554,23 @@  static int imx6_pcie_attach_pd(struct device *dev)
 
 static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
-	struct dw_pcie *pci = imx6_pcie->pci;
-	struct device *dev = pci->dev;
 	unsigned int offset;
 	int ret = 0;
 
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX6SX:
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_INBOUND_AXI)) {
 		ret = clk_prepare_enable(imx6_pcie->pcie_inbound_axi);
-		if (ret) {
-			dev_err(dev, "unable to enable pcie_axi clock\n");
-			break;
-		}
+		if (ret)
+			return ret;
+	}
 
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_AUX)) {
+		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
+		if (ret)
+			return ret;
+	}
+
+	switch (imx6_pcie->drvdata->variant) {
+	case IMX6SX:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR12,
 				   IMX6SX_GPR12_PCIE_TEST_POWERDOWN, 0);
 		break;
@@ -589,12 +597,6 @@  static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 	case IMX8MQ_EP:
 	case IMX8MP:
 	case IMX8MP_EP:
-		ret = clk_prepare_enable(imx6_pcie->pcie_aux);
-		if (ret) {
-			dev_err(dev, "unable to enable pcie_aux clock\n");
-			break;
-		}
-
 		offset = imx6_pcie_grp_offset(imx6_pcie);
 		/*
 		 * Set the over ride low and enabled
@@ -614,10 +616,13 @@  static int imx6_pcie_enable_ref_clk(struct imx6_pcie *imx6_pcie)
 
 static void imx6_pcie_disable_ref_clk(struct imx6_pcie *imx6_pcie)
 {
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX6SX:
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_INBOUND_AXI))
 		clk_disable_unprepare(imx6_pcie->pcie_inbound_axi);
-		break;
+
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_AUX))
+		clk_disable_unprepare(imx6_pcie->pcie_aux);
+
+	switch (imx6_pcie->drvdata->variant) {
 	case IMX6QP:
 	case IMX6Q:
 		regmap_update_bits(imx6_pcie->iomuxc_gpr, IOMUXC_GPR1,
@@ -631,14 +636,6 @@  static void imx6_pcie_disable_ref_clk(struct imx6_pcie *imx6_pcie)
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL,
 				   IMX7D_GPR12_PCIE_PHY_REFCLK_SEL);
 		break;
-	case IMX8MM:
-	case IMX8MM_EP:
-	case IMX8MQ:
-	case IMX8MQ_EP:
-	case IMX8MP:
-	case IMX8MP_EP:
-		clk_disable_unprepare(imx6_pcie->pcie_aux);
-		break;
 	default:
 		break;
 	}
@@ -1316,21 +1313,21 @@  static int imx6_pcie_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie),
 				     "pcie clock source missing or invalid\n");
 
-	switch (imx6_pcie->drvdata->variant) {
-	case IMX6SX:
-		imx6_pcie->pcie_inbound_axi = devm_clk_get(dev,
-							   "pcie_inbound_axi");
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_INBOUND_AXI)) {
+		imx6_pcie->pcie_inbound_axi = devm_clk_get(dev, "pcie_inbound_axi");
 		if (IS_ERR(imx6_pcie->pcie_inbound_axi))
-			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_inbound_axi),
-					     "pcie_inbound_axi clock missing or invalid\n");
-		break;
-	case IMX8MQ:
-	case IMX8MQ_EP:
+			dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_inbound_axi),
+				      "pcie_inbound_axi clock missing or invalid\n");
+	}
+
+	if (imx6_check_flag(imx6_pcie, IMX6_PCIE_FLAG_HAS_CLK_AUX)) {
 		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
 		if (IS_ERR(imx6_pcie->pcie_aux))
 			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_aux),
 					     "pcie_aux clock source missing or invalid\n");
-		fallthrough;
+	}
+
+	switch (imx6_pcie->drvdata->variant) {
 	case IMX7D:
 		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
 			imx6_pcie->controller_id = 1;
@@ -1353,10 +1350,6 @@  static int imx6_pcie_probe(struct platform_device *pdev)
 	case IMX8MM_EP:
 	case IMX8MP:
 	case IMX8MP_EP:
-		imx6_pcie->pcie_aux = devm_clk_get(dev, "pcie_aux");
-		if (IS_ERR(imx6_pcie->pcie_aux))
-			return dev_err_probe(dev, PTR_ERR(imx6_pcie->pcie_aux),
-					     "pcie_aux clock source missing or invalid\n");
 		imx6_pcie->apps_reset = devm_reset_control_get_exclusive(dev,
 									 "apps");
 		if (IS_ERR(imx6_pcie->apps_reset))
@@ -1482,7 +1475,8 @@  static const struct imx6_pcie_drvdata drvdata[] = {
 		.variant = IMX6SX,
 		.flags = IMX6_PCIE_FLAG_IMX6_PHY |
 			 IMX6_PCIE_FLAG_IMX6_SPEED_CHANGE |
-			 IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
+			 IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
+			 IMX6_PCIE_FLAG_HAS_CLK_INBOUND_AXI,
 		.gpr = "fsl,imx6q-iomuxc-gpr",
 	},
 	[IMX6QP] = {
@@ -1500,30 +1494,36 @@  static const struct imx6_pcie_drvdata drvdata[] = {
 	},
 	[IMX8MQ] = {
 		.variant = IMX8MQ,
+		.flags = IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.gpr = "fsl,imx8mq-iomuxc-gpr",
 	},
 	[IMX8MM] = {
 		.variant = IMX8MM,
-		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
+		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
+			 IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.gpr = "fsl,imx8mm-iomuxc-gpr",
 	},
 	[IMX8MP] = {
 		.variant = IMX8MP,
-		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND,
+		.flags = IMX6_PCIE_FLAG_SUPPORTS_SUSPEND |
+			 IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.gpr = "fsl,imx8mp-iomuxc-gpr",
 	},
 	[IMX8MQ_EP] = {
 		.variant = IMX8MQ_EP,
+		.flags = IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.mode = DW_PCIE_EP_TYPE,
 		.gpr = "fsl,imx8mq-iomuxc-gpr",
 	},
 	[IMX8MM_EP] = {
 		.variant = IMX8MM_EP,
+		.flags = IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.mode = DW_PCIE_EP_TYPE,
 		.gpr = "fsl,imx8mm-iomuxc-gpr",
 	},
 	[IMX8MP_EP] = {
 		.variant = IMX8MP_EP,
+		.flags = IMX6_PCIE_FLAG_HAS_CLK_AUX,
 		.mode = DW_PCIE_EP_TYPE,
 		.gpr = "fsl,imx8mp-iomuxc-gpr",
 	},