[PATCH v2 09/13] i3c: dw-i3c-master: Add a quirk to skip clock and reset

[Akhil R <akhilrajeev@nvidia.com>]

Some ACPI-enumerated devices like Tegra410 do not have clock and reset
resources exposed via the clk/reset frameworks. Add a match data for
such devices to skip acquiring clock and reset controls during probe.

Move match data parsing before clock/reset acquisition so the quirk is
available early enough.  When the quirk is set, fall back to reading
the clock rate from the "clock-frequency" device property instead.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 drivers/i3c/master/dw-i3c-master.c | 60 +++++++++++++++++++-----------
 1 file changed, 39 insertions(+), 21 deletions(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 05ccdf177b6d..a62eec6d2ac0 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -241,6 +241,7 @@
 /* List of quirks */
 #define AMD_I3C_OD_PP_TIMING		BIT(1)
 #define DW_I3C_DISABLE_RUNTIME_PM_QUIRK	BIT(2)
+#define DW_I3C_ACPI_SKIP_CLK_RST		BIT(3)
 
 struct dw_i3c_cmd {
 	u32 cmd_lo;
@@ -560,13 +561,26 @@ static void dw_i3c_master_set_intr_regs(struct dw_i3c_master *master)
 	writel(IBI_REQ_REJECT_ALL, master->regs + IBI_MR_REQ_REJECT);
 }
 
+static unsigned long dw_i3c_master_get_core_rate(struct dw_i3c_master *master)
+{
+	unsigned int core_rate_prop;
+
+	if (!(master->quirks & DW_I3C_ACPI_SKIP_CLK_RST))
+		return clk_get_rate(master->core_clk);
+
+	if (device_property_read_u32(master->dev, "clock-frequency", &core_rate_prop))
+		return 0;
+
+	return core_rate_prop;
+}
+
 static int dw_i3c_clk_cfg(struct dw_i3c_master *master)
 {
 	unsigned long core_rate, core_period;
 	u32 scl_timing;
 	u8 hcnt, lcnt;
 
-	core_rate = clk_get_rate(master->core_clk);
+	core_rate = dw_i3c_master_get_core_rate(master);
 	if (!core_rate)
 		return -EINVAL;
 
@@ -619,7 +633,7 @@ static int dw_i2c_clk_cfg(struct dw_i3c_master *master)
 	u16 hcnt, lcnt;
 	u32 scl_timing;
 
-	core_rate = clk_get_rate(master->core_clk);
+	core_rate = dw_i3c_master_get_core_rate(master);
 	if (!core_rate)
 		return -EINVAL;
 
@@ -1600,21 +1614,34 @@ int dw_i3c_common_probe(struct dw_i3c_master *master,
 	if (IS_ERR(master->regs))
 		return PTR_ERR(master->regs);
 
-	master->core_clk = devm_clk_get_enabled(&pdev->dev, NULL);
-	if (IS_ERR(master->core_clk))
-		return PTR_ERR(master->core_clk);
+	if (has_acpi_companion(&pdev->dev)) {
+		quirks = (unsigned long)device_get_match_data(&pdev->dev);
+	} else if (pdev->dev.of_node) {
+		drvdata = device_get_match_data(&pdev->dev);
+		if (drvdata)
+			quirks = drvdata->flags;
+	}
+	master->quirks = quirks;
+
+	if (master->quirks & DW_I3C_ACPI_SKIP_CLK_RST) {
+		master->core_clk = NULL;
+		master->core_rst = NULL;
+	} else {
+		master->core_clk = devm_clk_get_enabled(&pdev->dev, NULL);
+		if (IS_ERR(master->core_clk))
+			return PTR_ERR(master->core_clk);
+
+		master->core_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
+									     "core_rst");
+		if (IS_ERR(master->core_rst))
+			return PTR_ERR(master->core_rst);
+		reset_control_deassert(master->core_rst);
+	}
 
 	master->pclk = devm_clk_get_optional_enabled(&pdev->dev, "pclk");
 	if (IS_ERR(master->pclk))
 		return PTR_ERR(master->pclk);
 
-	master->core_rst = devm_reset_control_get_optional_exclusive(&pdev->dev,
-								    "core_rst");
-	if (IS_ERR(master->core_rst))
-		return PTR_ERR(master->core_rst);
-
-	reset_control_deassert(master->core_rst);
-
 	spin_lock_init(&master->xferqueue.lock);
 	INIT_LIST_HEAD(&master->xferqueue.list);
 
@@ -1647,15 +1674,6 @@ int dw_i3c_common_probe(struct dw_i3c_master *master,
 	master->maxdevs = ret >> 16;
 	master->free_pos = GENMASK(master->maxdevs - 1, 0);
 
-	if (has_acpi_companion(&pdev->dev)) {
-		quirks = (unsigned long)device_get_match_data(&pdev->dev);
-	} else if (pdev->dev.of_node) {
-		drvdata = device_get_match_data(&pdev->dev);
-		if (drvdata)
-			quirks = drvdata->flags;
-	}
-	master->quirks = quirks;
-
 	/* Keep controller enabled by preventing runtime suspend */
 	if (master->quirks & DW_I3C_DISABLE_RUNTIME_PM_QUIRK)
 		pm_runtime_get_noresume(&pdev->dev);
-- 
2.50.1