From: Biju Das <biju.das.jz@bp.renesas.com>

The General PWM Timer (GPT) is capable of detecting "dead time error
and short-circuits between output pins" and send Output disable
request to poeg(Port Output Enable for GPT).

Add support for linking poeg group with gpt, so that gpt can control
the output disable function.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
V24 from [1] -> v8:
 * Replaced return type of rzg2l_gpt_poeg_init() from void->int and
   probe() checks this return value.
 * Added more error checks in rzg2l_gpt_poeg_init() 

[1] https://lore.kernel.org/all/20250226144531.176819-1-biju.das.jz@bp.renesas.com/
---
 drivers/pwm/pwm-rzg2l-gpt.c | 95 +++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/drivers/pwm/pwm-rzg2l-gpt.c b/drivers/pwm/pwm-rzg2l-gpt.c
index 38ad03ded9ce..aabd2d576231 100644
--- a/drivers/pwm/pwm-rzg2l-gpt.c
+++ b/drivers/pwm/pwm-rzg2l-gpt.c
@@ -39,6 +39,7 @@
 #define RZG2L_GTCR(ch)		(0x2c + RZG2L_GET_CH_OFFS(ch))
 #define RZG2L_GTUDDTYC(ch)	(0x30 + RZG2L_GET_CH_OFFS(ch))
 #define RZG2L_GTIOR(ch)		(0x34 + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTINTAD(ch)	(0x38 + RZG2L_GET_CH_OFFS(ch))
 #define RZG2L_GTBER(ch)		(0x40 + RZG2L_GET_CH_OFFS(ch))
 #define RZG2L_GTCNT(ch)		(0x48 + RZG2L_GET_CH_OFFS(ch))
 #define RZG2L_GTCCR(ch, sub_ch)	(0x4c + RZG2L_GET_CH_OFFS(ch) + 4 * (sub_ch))
@@ -55,12 +56,21 @@
 #define RZG2L_GTUDDTYC_UP_COUNTING	(RZG2L_GTUDDTYC_UP | RZG2L_GTUDDTYC_UDF)
 
 #define RZG2L_GTIOR_GTIOA	GENMASK(4, 0)
+#define RZG2L_GTIOR_OADF	GENMASK(10, 9)
 #define RZG2L_GTIOR_GTIOB	GENMASK(20, 16)
+#define RZG2L_GTIOR_OBDF	GENMASK(26, 25)
+
 #define RZG2L_GTIOR_GTIOx(sub_ch)	((sub_ch) ? RZG2L_GTIOR_GTIOB : RZG2L_GTIOR_GTIOA)
+
 #define RZG2L_GTIOR_OAE		BIT(8)
 #define RZG2L_GTIOR_OBE		BIT(24)
 #define RZG2L_GTIOR_OxE(sub_ch)		((sub_ch) ? RZG2L_GTIOR_OBE : RZG2L_GTIOR_OAE)
 
+#define RZG2L_GTIOR_OADF_HIGH_IMP_ON_OUT_DISABLE	BIT(9)
+#define RZG2L_GTIOR_OBDF_HIGH_IMP_ON_OUT_DISABLE	BIT(25)
+#define RZG2L_GTIOR_PIN_DISABLE_SETTING \
+	(RZG2L_GTIOR_OADF_HIGH_IMP_ON_OUT_DISABLE | RZG2L_GTIOR_OBDF_HIGH_IMP_ON_OUT_DISABLE)
+
 #define RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE	0x1b
 #define RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH \
 	(RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE | RZG2L_GTIOR_OAE)
@@ -71,12 +81,17 @@
 	((sub_ch) ? RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH : \
 	 RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH)
 
+#define RZG2L_GTINTAD_GRP_MASK	GENMASK(25, 24)
+
 #define RZG2L_MAX_HW_CHANNELS	8
 #define RZG2L_CHANNELS_PER_IO	2
 #define RZG2L_MAX_PWM_CHANNELS	(RZG2L_MAX_HW_CHANNELS * RZG2L_CHANNELS_PER_IO)
 #define RZG2L_MAX_SCALE_FACTOR	1024
 #define RZG2L_MAX_TICKS		((u64)U32_MAX * RZG2L_MAX_SCALE_FACTOR)
 
+#define RZG2L_MAX_POEG_GROUPS	4
+#define RZG2L_LAST_POEG_GROUP	3
+
 struct rzg2l_gpt_chip {
 	void __iomem *mmio;
 	struct mutex lock; /* lock to protect shared channel resources */
@@ -84,6 +99,7 @@ struct rzg2l_gpt_chip {
 	u32 period_ticks[RZG2L_MAX_HW_CHANNELS];
 	u32 channel_request_count[RZG2L_MAX_HW_CHANNELS];
 	u32 channel_enable_count[RZG2L_MAX_HW_CHANNELS];
+	DECLARE_BITMAP(poeg_gpt_link, RZG2L_MAX_POEG_GROUPS * RZG2L_MAX_HW_CHANNELS);
 };
 
 static inline struct rzg2l_gpt_chip *to_rzg2l_gpt_chip(struct pwm_chip *chip)
@@ -379,6 +395,81 @@ static const struct pwm_ops rzg2l_gpt_ops = {
 	.apply = rzg2l_gpt_apply,
 };
 
+/*
+ * This function links a poeg group{A,B,C,D} with a gpt channel{0..7} and
+ * configure the pin for output disable.
+ */
+static int rzg2l_gpt_poeg_init(struct platform_device *pdev,
+			       struct rzg2l_gpt_chip *rzg2l_gpt)
+{
+	const char *poeg_name = "renesas,poegs";
+	struct of_phandle_args of_args;
+	struct property *poegs;
+	unsigned int i;
+	u32 poeg_grp;
+	u32 bitpos;
+	int cells;
+	int ret;
+
+	poegs =  of_find_property(pdev->dev.of_node, poeg_name, NULL);
+	if (!poegs)
+		return 0;
+
+	cells = of_property_count_u32_elems(pdev->dev.of_node, poeg_name);
+	if (cells < 0)
+		return cells;
+
+	if (cells & 1)
+		return -EINVAL;
+
+	cells >>= 1;
+	for (i = 0; i < cells; i++) {
+		ret = of_parse_phandle_with_fixed_args(pdev->dev.of_node,
+						       poeg_name, 1, i,
+						       &of_args);
+		if (ret)
+			return ret;
+
+		if (of_args.args[0] >= RZG2L_MAX_HW_CHANNELS) {
+			dev_err(&pdev->dev, "Invalid channel %d >= %d\n",
+				of_args.args[0], RZG2L_MAX_HW_CHANNELS);
+			goto err_of_node;
+		}
+
+		if (!of_device_is_available(of_args.np)) {
+			/* It's fine to have a phandle to a non-enabled poeg. */
+			of_node_put(of_args.np);
+			continue;
+		}
+
+		if (!of_property_read_u32(of_args.np, "renesas,poeg-id", &poeg_grp)) {
+			if (poeg_grp > RZG2L_LAST_POEG_GROUP) {
+				dev_err(&pdev->dev, "Invalid poeg group %d > %d\n",
+					poeg_grp, RZG2L_LAST_POEG_GROUP);
+				goto err_of_node;
+			}
+
+			bitpos = of_args.args[0] + poeg_grp * RZG2L_MAX_HW_CHANNELS;
+			set_bit(bitpos, rzg2l_gpt->poeg_gpt_link);
+
+			rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTINTAD(of_args.args[0]),
+					 RZG2L_GTINTAD_GRP_MASK, poeg_grp << 24);
+
+			rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTIOR(of_args.args[0]),
+					 RZG2L_GTIOR_OBDF | RZG2L_GTIOR_OADF,
+					 RZG2L_GTIOR_PIN_DISABLE_SETTING);
+		}
+
+		of_node_put(of_args.np);
+	}
+
+	return 0;
+
+err_of_node:
+	of_node_put(of_args.np);
+	return -EINVAL;
+}
+
 static int rzg2l_gpt_probe(struct platform_device *pdev)
 {
 	struct rzg2l_gpt_chip *rzg2l_gpt;
@@ -430,6 +521,10 @@ static int rzg2l_gpt_probe(struct platform_device *pdev)
 	if (rzg2l_gpt->rate_khz * KILO != rate)
 		return dev_err_probe(dev, -EINVAL, "Rate is not multiple of 1000");
 
+	ret = rzg2l_gpt_poeg_init(pdev, rzg2l_gpt);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to link gpt with poeg\n");
+
 	mutex_init(&rzg2l_gpt->lock);
 
 	chip->ops = &rzg2l_gpt_ops;
-- 
2.43.0