clk: at91: clk-utmi: add utmi support for sama7g5

Add UTMI support for SAMA7G5. SAMA7G5's UTMI control is done via
XTALF register. Values written at bits 2..0 in this register
correspond to the on board crystal oscillator frequency.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-18-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: claudiubeznea

drivers/clk/at91/clk-utmi.c

@@ -120,9 +120,11 @@ static const struct clk_ops utmi_ops = {
 	.recalc_rate = clk_utmi_recalc_rate,
 };
 
-struct clk_hw * __init
-at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
-		       const char *name, const char *parent_name)
+static struct clk_hw * __init
+at91_clk_register_utmi_internal(struct regmap *regmap_pmc,
+				struct regmap *regmap_sfr,
+				const char *name, const char *parent_name,
+				const struct clk_ops *ops, unsigned long flags)
 {
 	struct clk_utmi *utmi;
 	struct clk_hw *hw;
@@ -134,10 +136,10 @@ at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
 		return ERR_PTR(-ENOMEM);
 
 	init.name = name;
-	init.ops = &utmi_ops;
+	init.ops = ops;
 	init.parent_names = parent_name ? &parent_name : NULL;
 	init.num_parents = parent_name ? 1 : 0;
-	init.flags = CLK_SET_RATE_GATE;
+	init.flags = flags;
 
 	utmi->hw.init = &init;
 	utmi->regmap_pmc = regmap_pmc;
@@ -152,3 +154,94 @@ at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
 
 	return hw;
 }
+
+struct clk_hw * __init
+at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
+		       const char *name, const char *parent_name)
+{
+	return at91_clk_register_utmi_internal(regmap_pmc, regmap_sfr, name,
+			parent_name, &utmi_ops, CLK_SET_RATE_GATE);
+}
+
+static int clk_utmi_sama7g5_prepare(struct clk_hw *hw)
+{
+	struct clk_utmi *utmi = to_clk_utmi(hw);
+	struct clk_hw *hw_parent;
+	unsigned long parent_rate;
+	unsigned int val;
+
+	hw_parent = clk_hw_get_parent(hw);
+	parent_rate = clk_hw_get_rate(hw_parent);
+
+	switch (parent_rate) {
+	case 16000000:
+		val = 0;
+		break;
+	case 20000000:
+		val = 2;
+		break;
+	case 24000000:
+		val = 3;
+		break;
+	case 32000000:
+		val = 5;
+		break;
+	default:
+		pr_err("UTMICK: unsupported main_xtal rate\n");
+		return -EINVAL;
+	}
+
+	regmap_write(utmi->regmap_pmc, AT91_PMC_XTALF, val);
+
+	return 0;
+
+}
+
+static int clk_utmi_sama7g5_is_prepared(struct clk_hw *hw)
+{
+	struct clk_utmi *utmi = to_clk_utmi(hw);
+	struct clk_hw *hw_parent;
+	unsigned long parent_rate;
+	unsigned int val;
+
+	hw_parent = clk_hw_get_parent(hw);
+	parent_rate = clk_hw_get_rate(hw_parent);
+
+	regmap_read(utmi->regmap_pmc, AT91_PMC_XTALF, &val);
+	switch (val & 0x7) {
+	case 0:
+		if (parent_rate == 16000000)
+			return 1;
+		break;
+	case 2:
+		if (parent_rate == 20000000)
+			return 1;
+		break;
+	case 3:
+		if (parent_rate == 24000000)
+			return 1;
+		break;
+	case 5:
+		if (parent_rate == 32000000)
+			return 1;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct clk_ops sama7g5_utmi_ops = {
+	.prepare = clk_utmi_sama7g5_prepare,
+	.is_prepared = clk_utmi_sama7g5_is_prepared,
+	.recalc_rate = clk_utmi_recalc_rate,
+};
+
+struct clk_hw * __init
+at91_clk_sama7g5_register_utmi(struct regmap *regmap_pmc, const char *name,
+			       const char *parent_name)
+{
+	return at91_clk_register_utmi_internal(regmap_pmc, NULL, name,
+			parent_name, &sama7g5_utmi_ops, 0);
+}

drivers/clk/at91/pmc.h

@@ -236,6 +236,10 @@ struct clk_hw * __init
 at91_clk_register_utmi(struct regmap *regmap_pmc, struct regmap *regmap_sfr,
 		       const char *name, const char *parent_name);
 
+struct clk_hw * __init
+at91_clk_sama7g5_register_utmi(struct regmap *regmap, const char *name,
+			       const char *parent_name);
+
 #ifdef CONFIG_PM
 void pmc_register_id(u8 id);
 void pmc_register_pck(u8 pck);

include/linux/clk/at91_pmc.h

@@ -137,6 +137,8 @@
 #define			AT91_PMC_PLLADIV2_ON		(1 << 12)
 #define		AT91_PMC_H32MXDIV	BIT(24)
 
+#define AT91_PMC_XTALF		0x34			/* Main XTAL Frequency Register [SAMA7G5 only] */
+
 #define	AT91_PMC_USB		0x38			/* USB Clock Register [some SAM9 only] */
 #define		AT91_PMC_USBS		(0x1 <<  0)		/* USB OHCI Input clock selection */
 #define			AT91_PMC_USBS_PLLA		(0 << 0)