[PATCH v5 21/44] clk: davinci: New driver for TI DA8XX USB PHY clocks

[David Lechner]

This adds a new driver for the USB PHY clocks in the CFGCHIP2 syscon
register on TI DA8XX-type SoCs.

The USB0 (USB 2.0) PHY clock is an interesting case because it calls
clk_enable() in a reentrant way. The USB 2.0 PSC only has to be enabled
temporarily while we are locking the PLL, which takes place during the
clk_enable() callback.

Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---
 drivers/clk/davinci/Makefile            |   1 +
 drivers/clk/davinci/da8xx-usb-phy-clk.c | 425 ++++++++++++++++++++++++++++++++
 include/linux/clk/davinci.h             |  13 +
 3 files changed, 439 insertions(+)
 create mode 100644 drivers/clk/davinci/da8xx-usb-phy-clk.c

diff --git a/drivers/clk/davinci/Makefile b/drivers/clk/davinci/Makefile
index 11178b7..4c772a7 100644
--- a/drivers/clk/davinci/Makefile
+++ b/drivers/clk/davinci/Makefile
@@ -2,6 +2,7 @@
 
 ifeq ($(CONFIG_COMMON_CLK), y)
 obj-$(CONFIG_ARCH_DAVINCI_DA8XX)	+= da8xx-cfgchip.o
+obj-$(CONFIG_ARCH_DAVINCI_DA8XX)	+= da8xx-usb-phy-clk.o
 
 obj-y += pll.o
 obj-$(CONFIG_ARCH_DAVINCI_DA830)	+= pll-da830.o
diff --git a/drivers/clk/davinci/da8xx-usb-phy-clk.c b/drivers/clk/davinci/da8xx-usb-phy-clk.c
new file mode 100644
index 0000000..fc6ea07
--- /dev/null
+++ b/drivers/clk/davinci/da8xx-usb-phy-clk.c
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * da8xx-usb-phy-clk - TI DaVinci DA8xx USB PHY clocks driver
+ *
+ * Copyright (C) 2017 David Lechner <david@xxxxxxxxxxxxxx>
+ *
+ * This driver exposes the USB PHY clocks on DA8xx/AM18xx/OMAP-L13x SoCs.
+ * The clocks consist of two muxes and a PLL. The USB 2.0 PHY mux and PLL are
+ * combined into a single clock in Linux. The USB 1.0 PHY clock just consists
+ * of a mux. These clocks are controlled through CFGCHIP2, which is accessed
+ * as a syscon regmap since it is shared with other devices.
+ */
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/mfd/da8xx-cfgchip.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+/* --- USB 2.0 PHY clock --- */
+
+struct da8xx_usb0_phy_clk {
+	struct clk_hw hw;
+	struct clk *clk;
+	struct regmap *regmap;
+};
+
+enum da8xx_usb0_phy_clk_parent {
+	DA8XX_USB0_PHY_CLK_PARENT_USB_REFCLKIN,
+	DA8XX_USB0_PHY_CLK_PARENT_PLL0_AUXCLK,
+};
+
+#define to_da8xx_usb0_phy_clk(_hw) \
+	container_of((_hw), struct da8xx_usb0_phy_clk, hw)
+
+static int da8xx_usb0_phy_clk_prepare(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+
+	/* The USB 2.0 PSC clock is only needed temporarily during the USB 2.0
+	 * PHY clock enable, but since clk_prepare() can't be called in an
+	 * atomic context (i.e. in clk_enable()), we have to prepare it here.
+	 */
+	return clk_prepare(clk->clk);
+}
+
+static void da8xx_usb0_phy_clk_unprepare(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+
+	clk_unprepare(clk->clk);
+}
+
+static int da8xx_usb0_phy_clk_enable(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int mask, val;
+	int ret;
+
+	/* Locking the USB 2.O PLL requires that the USB 2.O PSC is enabled
+	 * temporaily. It can be turned back off once the PLL is locked.
+	 */
+	clk_enable(clk->clk);
+
+	/* Turn on the USB 2.0 PHY, but just the PLL, and not OTG. The USB 1.1
+	 * PHY may use the USB 2.0 PLL clock without USB 2.0 OTG being used.
+	 */
+	mask = CFGCHIP2_RESET | CFGCHIP2_PHYPWRDN | CFGCHIP2_PHY_PLLON;
+	val = CFGCHIP2_PHY_PLLON;
+
+	regmap_write_bits(clk->regmap, CFGCHIP(2), mask, val);
+	ret = regmap_read_poll_timeout(clk->regmap, CFGCHIP(2), val,
+				       val & CFGCHIP2_PHYCLKGD, 0, 500000);
+
+	clk_disable(clk->clk);
+
+	return ret;
+}
+
+static void da8xx_usb0_phy_clk_disable(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int val;
+
+	val = CFGCHIP2_PHYPWRDN;
+	regmap_write_bits(clk->regmap, CFGCHIP(2), val, val);
+}
+
+static int da8xx_usb0_phy_clk_is_enabled(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int val;
+
+	regmap_read(clk->regmap, CFGCHIP(2), &val);
+
+	return !!(val & CFGCHIP2_PHYCLKGD);
+}
+
+static unsigned long da8xx_usb0_phy_clk_recalc_rate(struct clk_hw *hw,
+						    unsigned long parent_rate)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int mask, val;
+
+	/* The parent clock rate must be one of the following */
+	mask = CFGCHIP2_REFFREQ_MASK;
+	switch (parent_rate) {
+	case 12000000:
+		val = CFGCHIP2_REFFREQ_12MHZ;
+		break;
+	case 13000000:
+		val = CFGCHIP2_REFFREQ_13MHZ;
+		break;
+	case 19200000:
+		val = CFGCHIP2_REFFREQ_19_2MHZ;
+		break;
+	case 20000000:
+		val = CFGCHIP2_REFFREQ_20MHZ;
+		break;
+	case 24000000:
+		val = CFGCHIP2_REFFREQ_24MHZ;
+		break;
+	case 26000000:
+		val = CFGCHIP2_REFFREQ_26MHZ;
+		break;
+	case 38400000:
+		val = CFGCHIP2_REFFREQ_38_4MHZ;
+		break;
+	case 40000000:
+		val = CFGCHIP2_REFFREQ_40MHZ;
+		break;
+	case 48000000:
+		val = CFGCHIP2_REFFREQ_48MHZ;
+		break;
+	default:
+		return 0;
+	}
+
+	regmap_write_bits(clk->regmap, CFGCHIP(2), mask, val);
+
+	/* USB 2.0 PLL always supplies 48MHz */
+	return 48000000;
+}
+
+static long da8xx_usb0_phy_clk_round_rate(struct clk_hw *hw, unsigned long rate,
+					  unsigned long *parent_rate)
+{
+	return 48000000;
+}
+
+static int da8xx_usb0_phy_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int mask, val;
+
+	/* Set the mux depending on the parent clock. */
+	mask = CFGCHIP2_USB2PHYCLKMUX;
+	switch (index) {
+	case DA8XX_USB0_PHY_CLK_PARENT_USB_REFCLKIN:
+		val = 0;
+		break;
+	case DA8XX_USB0_PHY_CLK_PARENT_PLL0_AUXCLK:
+		val = CFGCHIP2_USB2PHYCLKMUX;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	regmap_write_bits(clk->regmap, CFGCHIP(2), mask, val);
+
+	return 0;
+}
+
+static u8 da8xx_usb0_phy_clk_get_parent(struct clk_hw *hw)
+{
+	struct da8xx_usb0_phy_clk *clk = to_da8xx_usb0_phy_clk(hw);
+	unsigned int val;
+
+	regmap_read(clk->regmap, CFGCHIP(2), &val);
+
+	if (val & CFGCHIP2_USB2PHYCLKMUX)
+		return DA8XX_USB0_PHY_CLK_PARENT_PLL0_AUXCLK;
+
+	return DA8XX_USB0_PHY_CLK_PARENT_USB_REFCLKIN;
+}
+
+static const struct clk_ops da8xx_usb0_phy_clk_ops = {
+	.prepare	= da8xx_usb0_phy_clk_prepare,
+	.unprepare	= da8xx_usb0_phy_clk_unprepare,
+	.enable		= da8xx_usb0_phy_clk_enable,
+	.disable	= da8xx_usb0_phy_clk_disable,
+	.is_enabled	= da8xx_usb0_phy_clk_is_enabled,
+	.recalc_rate	= da8xx_usb0_phy_clk_recalc_rate,
+	.round_rate	= da8xx_usb0_phy_clk_round_rate,
+	.set_parent	= da8xx_usb0_phy_clk_set_parent,
+	.get_parent	= da8xx_usb0_phy_clk_get_parent,
+};
+
+/**
+ * da8xx_usb0_phy_clk_register - Register a new USB 2.0 PHY clock
+ * @name: The clock name
+ * @parent0: The name of the USB_REFCLKIN clock
+ * @parent1: The name of the PLL0 AUXCLK
+ * @usb0_psc_clk: The USB 2.0 PSC clock
+ * @regmap: The CFGCHIP regmap
+ */
+struct clk *da8xx_usb0_phy_clk_register(const char *name,
+					const char *parent0,
+					const char *parent1,
+					struct clk *usb0_psc_clk,
+					struct regmap *regmap)
+{
+	const char * const parent_names[] = {
+		[DA8XX_USB0_PHY_CLK_PARENT_USB_REFCLKIN] = parent0,
+		[DA8XX_USB0_PHY_CLK_PARENT_PLL0_AUXCLK] = parent1,
+	};
+	struct da8xx_usb0_phy_clk *clk;
+	struct clk_init_data init;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &da8xx_usb0_phy_clk_ops;
+	init.parent_names = parent_names;
+	init.num_parents = 2;
+
+	clk->hw.init = &init;
+	clk->clk = usb0_psc_clk;
+	clk->regmap = regmap;
+
+	return clk_register(NULL, &clk->hw);
+}
+
+/* --- USB 1.1 PHY clock --- */
+
+struct da8xx_usb1_phy_clk {
+	struct clk_hw hw;
+	struct regmap *regmap;
+};
+
+enum usb1_phy_clk_parent {
+	DA8XX_USB1_PHY_CLK_PARENT_USB0_PHY_PLL,
+	DA8XX_USB1_PHY_CLK_PARENT_USB_REFCLKIN,
+};
+
+#define to_da8xx_usb1_phy_clk(_hw) \
+	container_of((_hw), struct da8xx_usb1_phy_clk, hw)
+
+static int da8xx_usb1_phy_clk_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct da8xx_usb1_phy_clk *clk = to_da8xx_usb1_phy_clk(hw);
+	unsigned int mask, val;
+
+	/* Set the USB 1.1 PHY clock mux based on the parent clock. */
+	mask = CFGCHIP2_USB1PHYCLKMUX;
+	switch (index) {
+	case DA8XX_USB1_PHY_CLK_PARENT_USB_REFCLKIN:
+		val = CFGCHIP2_USB1PHYCLKMUX;
+		break;
+	case DA8XX_USB1_PHY_CLK_PARENT_USB0_PHY_PLL:
+		val = 0;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	regmap_write_bits(clk->regmap, CFGCHIP(2), mask, val);
+
+	return 0;
+}
+
+static u8 da8xx_usb1_phy_clk_get_parent(struct clk_hw *hw)
+{
+	struct da8xx_usb1_phy_clk *clk = to_da8xx_usb1_phy_clk(hw);
+	unsigned int val;
+
+	regmap_read(clk->regmap, CFGCHIP(2), &val);
+
+	if (val & CFGCHIP2_USB1PHYCLKMUX)
+		return DA8XX_USB1_PHY_CLK_PARENT_USB_REFCLKIN;
+
+	return DA8XX_USB1_PHY_CLK_PARENT_USB0_PHY_PLL;
+}
+
+static const struct clk_ops da8xx_usb1_phy_clk_ops = {
+	.set_parent	= da8xx_usb1_phy_clk_set_parent,
+	.get_parent	= da8xx_usb1_phy_clk_get_parent,
+};
+
+/**
+ * da8xx_usb1_phy_clk_register - Register a new USB 1.1 PHY clock
+ * @name: The clock name
+ * @parent0: The name of the USB 2.0 PHY clock
+ * @parent1: The name of the USB_REFCLKIN clock
+ * @regmap: The CFGCHIP regmap
+ */
+struct clk *da8xx_usb1_phy_clk_register(const char *name,
+					const char *parent0,
+					const char *parent1,
+					struct regmap *regmap)
+{
+	const char * const parent_names[] = {
+		[DA8XX_USB1_PHY_CLK_PARENT_USB0_PHY_PLL] = parent0,
+		[DA8XX_USB1_PHY_CLK_PARENT_USB_REFCLKIN] = parent1,
+	};
+	struct da8xx_usb1_phy_clk *clk;
+	struct clk_init_data init;
+
+	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &da8xx_usb1_phy_clk_ops;
+	init.parent_names = parent_names;
+	init.num_parents = 2;
+
+	clk->hw.init = &init;
+	clk->regmap = regmap;
+
+	return clk_register(NULL, &clk->hw);
+}
+
+#ifdef CONFIG_OF
+static void da8xx_usb0_phy_clk_init(struct device_node *np)
+{
+	const char *name = np->name;
+	const char *parent0, *parent1;
+	struct regmap *regmap;
+	struct clk *usb0_psc_clk, *clk;
+	int ret;
+
+	regmap = syscon_node_to_regmap(of_get_parent(np));
+	if (IS_ERR(regmap)) {
+		pr_err("%s: No regmap for syscon parent of %s (%ld)\n",
+		       __func__, np->full_name, PTR_ERR(regmap));
+		return;
+	}
+
+	ret = of_property_match_string(np, "clock-names", "usb_refclkin");
+	parent0 = of_clk_get_parent_name(np, ret);
+	if (!parent0) {
+		pr_err("%s: Could not get usb_refclkin (%d)\n", __func__, ret);
+		return;
+	}
+
+	ret = of_property_match_string(np, "clock-names", "auxclk");
+	parent1 = of_clk_get_parent_name(np, ret);
+	if (!parent1) {
+		pr_err("%s: Could not get auxclk (%d)\n", __func__, ret);
+		return;
+	}
+
+	usb0_psc_clk = of_clk_get_by_name(np, "usb0_lpsc");
+	if (IS_ERR(usb0_psc_clk)) {
+		pr_err("%s: Could not get usb0_lpsc (%ld)\n", __func__,
+		       PTR_ERR(usb0_psc_clk));
+		return;
+	}
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	clk = da8xx_usb0_phy_clk_register(name, parent0, parent1, usb0_psc_clk,
+					  regmap);
+	if (IS_ERR(clk)) {
+		pr_err("%s: Failed to register clock %s (%ld)\n",  __func__,
+		       np->full_name, PTR_ERR(clk));
+		clk_put(usb0_psc_clk);
+		return;
+	}
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+CLK_OF_DECLARE(da8xx_usb0_phy_clk, "ti,da830-usb0-phy-clock",
+	       da8xx_usb0_phy_clk_init);
+
+static void da8xx_usb1_phy_clk_init(struct device_node *np)
+{
+	const char *name = np->name;
+	const char *parent0, *parent1;
+	struct regmap *regmap;
+	struct clk *clk;
+	int ret;
+
+	regmap = syscon_node_to_regmap(of_get_parent(np));
+	if (IS_ERR(regmap)) {
+		pr_err("%s: No regmap for syscon parent of %s (%ld)\n",
+		       __func__, np->full_name, PTR_ERR(regmap));
+		return;
+	}
+
+	ret = of_property_match_string(np, "clock-names", "usb0_phy");
+	parent0 = of_clk_get_parent_name(np, ret);
+	if (!parent0) {
+		pr_err("%s: Could not get usb0_phy (%d)\n", __func__, ret);
+		return;
+	}
+
+	ret = of_property_match_string(np, "clock-names", "usb_refclkin");
+	parent1 = of_clk_get_parent_name(np, ret);
+	if (!parent1) {
+		pr_err("%s: Could not get usb_refclkin (%d)\n", __func__, ret);
+		return;
+	}
+
+	of_property_read_string(np, "clock-output-names", &name);
+
+	clk = da8xx_usb1_phy_clk_register(name, parent0, parent1, regmap);
+	if (IS_ERR(clk)) {
+		pr_err("%s: Failed to register clock %s (%ld)\n",
+		       __func__, np->full_name, PTR_ERR(clk));
+		return;
+	}
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+CLK_OF_DECLARE(da8xx_usb1_phy_clk, "ti,da830-usb1-phy-clock",
+	       da8xx_usb1_phy_clk_init);
+#endif
diff --git a/include/linux/clk/davinci.h b/include/linux/clk/davinci.h
index 3810ea3..ec7403e 100644
--- a/include/linux/clk/davinci.h
+++ b/include/linux/clk/davinci.h
@@ -9,6 +9,9 @@
 
 #include <linux/types.h>
 
+struct clk;
+struct regmap;
+
 void da830_pll_clk_init(void __iomem *pll);
 void da850_pll_clk_init(void __iomem *pll0, void __iomem *pll1);
 void dm355_pll_clk_init(void __iomem *pll1, void __iomem *pll2);
@@ -23,4 +26,14 @@ void dm365_psc_clk_init(void __iomem *psc);
 void dm644x_psc_clk_init(void __iomem *psc);
 void dm646x_psc_clk_init(void __iomem *psc);
 
+struct clk *da8xx_usb0_phy_clk_register(const char *name,
+					const char *parent0,
+					const char *parent1,
+					struct clk *usb0_psc_clk,
+					struct regmap *regmap);
+struct clk *da8xx_usb1_phy_clk_register(const char *name,
+					const char *parent0,
+					const char *parent1,
+					struct regmap *regmap);
+
 #endif /* __LINUX_CLK_DAVINCI_H__ */
-- 
2.7.4