[PATCH 08/10] i3c: master: dw-i3c-master: Fix OD_TIMING for spike filter

[dinesh.maniyam at intel.com]

From: Dinesh Maniyam <dinesh.maniyam at intel.com>

Fix the I3C device with spike filter unable to detect issue by setting
tHIGH_INIT to 200ns for first broadcast address.
This is according to MIPI SPEC 1.1.1 for first broadcast address
which is already part of linux upstreamed patch.

Signed-off-by: Dinesh Maniyam <dinesh.maniyam at intel.com>
---
 drivers/i3c/master/dw-i3c-master.c | 23 +++++++++++++++++++++++
 include/dw-i3c.h                   |  1 +
 include/linux/i3c/master.h         |  1 +
 3 files changed, 25 insertions(+)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index b3c5bf210c..af6e472f23 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -330,6 +330,14 @@ static int dw_i3c_clk_cfg(struct dw_i3c_master *master)
 	if (hcnt < SCL_I3C_TIMING_CNT_MIN)
 		hcnt = SCL_I3C_TIMING_CNT_MIN;
 
+	/* set back to THIGH_MAX_NS, after disable spike filter */
+	if (!master->first_broadcast) {
+		lcnt = SCL_I3C_TIMING_LCNT(readl(master->regs + SCL_I3C_OD_TIMING));
+		scl_timing = SCL_I3C_TIMING_HCNT(hcnt) | lcnt;
+		writel(scl_timing, master->regs + SCL_I3C_OD_TIMING);
+		return 0;
+	}
+
 	lcnt = DIV_ROUND_UP(core_rate, master->base.bus.scl_rate.i3c) - hcnt;
 	if (lcnt < SCL_I3C_TIMING_CNT_MIN)
 		lcnt = SCL_I3C_TIMING_CNT_MIN;
@@ -347,6 +355,9 @@ static int dw_i3c_clk_cfg(struct dw_i3c_master *master)
 	lcnt = max_t(u8,
 		     DIV_ROUND_UP(I3C_BUS_TLOW_OD_MIN_NS, core_period), lcnt);
 
+	/* first broadcast thigh to 200ns, to disable spike filter */
+	hcnt = DIV_ROUND_UP(I3C_BUS_THIGH_INIT_OD_MIN_NS, core_period);
+
 	scl_timing = SCL_I3C_TIMING_HCNT(hcnt) | SCL_I3C_TIMING_LCNT(lcnt);
 	writel(scl_timing, master->regs + SCL_I3C_OD_TIMING);
 
@@ -402,6 +413,9 @@ static int dw_i3c_master_bus_init(struct i3c_master_controller *m)
 	u32 thld_ctrl;
 	int ret;
 
+	/* first broadcast to disable spike filter */
+	master->first_broadcast = true;
+
 	switch (bus->mode) {
 	case I3C_BUS_MODE_MIXED_FAST:
 	case I3C_BUS_MODE_MIXED_LIMITED:
@@ -481,6 +495,15 @@ static void dw_i3c_master_irq_handler(struct dw_i3c_master *master)
 	if (status & INTR_TRANSFER_ERR_STAT)
 		writel(INTR_TRANSFER_ERR_STAT, master->regs + INTR_STATUS);
 
+	/* set back to THIGH_MAX_NS, after disable spike filter */
+	if (master->first_broadcast) {
+		master->first_broadcast = false;
+		int ret = dw_i3c_clk_cfg(master);
+
+		if (ret)
+			pr_err("Failed to set clk cfg\n");
+	}
+
 	spin_unlock(&master->xferqueue.lock);
 }
 
diff --git a/include/dw-i3c.h b/include/dw-i3c.h
index 920f18bccb..42c37d6dfa 100644
--- a/include/dw-i3c.h
+++ b/include/dw-i3c.h
@@ -240,6 +240,7 @@ struct dw_i3c_master {
 	char version[5];
 	char type[5];
 	u8 addrs[MAX_DEVS];
+	bool first_broadcast;
 };
 
 struct dw_i3c_i2c_dev_data {
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 759e689e2c..aefe593fc2 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -280,6 +280,7 @@ struct i3c_device {
 #define I3C_BUS_I2C_FM_PLUS_SCL_RATE	1000000
 #define I3C_BUS_I2C_FM_SCL_RATE		400000
 #define I3C_BUS_TLOW_OD_MIN_NS		200
+#define I3C_BUS_THIGH_INIT_OD_MIN_NS	200
 
 /**
  * enum i3c_bus_mode - I3C bus mode
-- 
2.26.2