Input: imx6ul_tsc - set glitch threshold by DTS property

Set the glitch threshold by DTS property and keep the existing default
behavior if the 'debounce-delay-us' is not present.

Signed-off-by: Dario Binacchi <[e-mail]>
Reviewed-by: Frank Li <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Dmitry Torokhov <[e-mail]>

drivers/input/touchscreen/imx6ul_tsc.c

···
 #define MEASURE_SIG_EN		BIT(0)
 #define VALID_SIG_EN		BIT(8)
 #define DE_GLITCH_MASK		GENMASK(30, 29)
-#define DE_GLITCH_2		0x02
+#define DE_GLITCH_DEF		0x02
 #define START_SENSE		BIT(12)
 #define TSC_DISABLE		BIT(16)
 #define DETECT_MODE		0x2
···
 	u32 pre_charge_time;
 	bool average_enable;
 	u32 average_select;
+	u32 de_glitch;
 
 	struct completion completion;
 };
···
 	basic_setting |= AUTO_MEASURE;
 	writel(basic_setting, tsc->tsc_regs + REG_TSC_BASIC_SETTING);
 
-	debug_mode2 = FIELD_PREP(DE_GLITCH_MASK, DE_GLITCH_2);
+	debug_mode2 = FIELD_PREP(DE_GLITCH_MASK, tsc->de_glitch);
 	writel(debug_mode2, tsc->tsc_regs + REG_TSC_DEBUG_MODE2);
 
 	writel(tsc->pre_charge_time, tsc->tsc_regs + REG_TSC_PRE_CHARGE_TIME);
···
 	int tsc_irq;
 	int adc_irq;
 	u32 average_samples;
+	u32 de_glitch;
 
 	tsc = devm_kzalloc(&pdev->dev, sizeof(*tsc), GFP_KERNEL);
 	if (!tsc)
···
 			"touchscreen-average-samples (%u) must be 1, 4, 8, 16 or 32\n",
 			average_samples);
 		return -EINVAL;
+	}
+
+	err = of_property_read_u32(np, "debounce-delay-us", &de_glitch);
+	if (err) {
+		tsc->de_glitch = DE_GLITCH_DEF;
+	} else {
+		u64 cycles;
+		unsigned long rate = clk_get_rate(tsc->tsc_clk);
+
+		cycles = DIV64_U64_ROUND_UP((u64)de_glitch * rate, USEC_PER_SEC);
+
+		if (cycles <= 0x3ff)
+			tsc->de_glitch = 3;
+		else if (cycles <= 0x7ff)
+			tsc->de_glitch = 2;
+		else if (cycles <= 0xfff)
+			tsc->de_glitch = 1;
+		else
+			tsc->de_glitch = 0;
 	}
 
 	err = input_register_device(tsc->input);