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Subject[PATCH v6 19/41] clk: davinci: New driver for TI DA8XX USB PHY clocks
Date
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@lechnology.com>
---

v6 changes:
- rename clocks to usb{0,1}_clk48
- rename USB 2.0 PSC clock to "fck"
- simplify {s,g}et_parent implementations
- use pr_fmt macro

drivers/clk/davinci/Makefile | 1 +
drivers/clk/davinci/da8xx-usb-phy-clk.c | 312 ++++++++++++++++++++++++++++++++
include/linux/clk/davinci.h | 6 +
3 files changed, 319 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..8dba40c
--- /dev/null
+++ b/drivers/clk/davinci/da8xx-usb-phy-clk.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * da8xx-usb-phy-clk - TI DaVinci DA8xx USB PHY clocks driver
+ *
+ * Copyright (C) 2018 David Lechner <david@lechnology.com>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt "\n", __func__
+
+#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_clk48 {
+ struct clk_hw hw;
+ struct clk *fck;
+ struct regmap *regmap;
+};
+
+#define to_da8xx_usb0_clk48(_hw) \
+ container_of((_hw), struct da8xx_usb0_clk48, hw)
+
+static int da8xx_usb0_clk48_prepare(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(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->fck);
+}
+
+static void da8xx_usb0_clk48_unprepare(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(hw);
+
+ clk_unprepare(clk->fck);
+}
+
+static int da8xx_usb0_clk48_enable(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(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->fck);
+
+ /* 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->fck);
+
+ return ret;
+}
+
+static void da8xx_usb0_clk48_disable(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(hw);
+ unsigned int val;
+
+ val = CFGCHIP2_PHYPWRDN;
+ regmap_write_bits(clk->regmap, CFGCHIP(2), val, val);
+}
+
+static int da8xx_usb0_clk48_is_enabled(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(hw);
+ unsigned int val;
+
+ regmap_read(clk->regmap, CFGCHIP(2), &val);
+
+ return !!(val & CFGCHIP2_PHYCLKGD);
+}
+
+static unsigned long da8xx_usb0_clk48_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(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_clk48_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ return 48000000;
+}
+
+static int da8xx_usb0_clk48_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(hw);
+
+ return regmap_write_bits(clk->regmap, CFGCHIP(2),
+ CFGCHIP2_USB2PHYCLKMUX,
+ index ? CFGCHIP2_USB2PHYCLKMUX : 0);
+}
+
+static u8 da8xx_usb0_clk48_get_parent(struct clk_hw *hw)
+{
+ struct da8xx_usb0_clk48 *clk = to_da8xx_usb0_clk48(hw);
+ unsigned int val;
+
+ regmap_read(clk->regmap, CFGCHIP(2), &val);
+
+ return (val & CFGCHIP2_USB2PHYCLKMUX) ? 1 : 0;
+}
+
+static const struct clk_ops da8xx_usb0_clk48_ops = {
+ .prepare = da8xx_usb0_clk48_prepare,
+ .unprepare = da8xx_usb0_clk48_unprepare,
+ .enable = da8xx_usb0_clk48_enable,
+ .disable = da8xx_usb0_clk48_disable,
+ .is_enabled = da8xx_usb0_clk48_is_enabled,
+ .recalc_rate = da8xx_usb0_clk48_recalc_rate,
+ .round_rate = da8xx_usb0_clk48_round_rate,
+ .set_parent = da8xx_usb0_clk48_set_parent,
+ .get_parent = da8xx_usb0_clk48_get_parent,
+};
+
+/**
+ * da8xx_cfgchip_register_usb0_clk48 - Register a new USB 2.0 PHY clock
+ * @regmap: The CFGCHIP regmap
+ * @fck_clk: The USB 2.0 PSC clock
+ */
+struct clk *da8xx_cfgchip_register_usb0_clk48(struct regmap *regmap,
+ struct clk *fck_clk)
+{
+ const char * const parent_names[] = { "usb_refclkin", "pll0_auxclk" };
+ struct da8xx_usb0_clk48 *clk;
+ struct clk_init_data init;
+
+ clk = kzalloc(sizeof(*clk), GFP_KERNEL);
+ if (!clk)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = "usb0_clk48";
+ init.ops = &da8xx_usb0_clk48_ops;
+ init.parent_names = parent_names;
+ init.num_parents = 2;
+
+ clk->hw.init = &init;
+ clk->fck = fck_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;
+};
+
+#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);
+
+ return regmap_write_bits(clk->regmap, CFGCHIP(2),
+ CFGCHIP2_USB1PHYCLKMUX,
+ index ? CFGCHIP2_USB1PHYCLKMUX : 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);
+
+ return (val & CFGCHIP2_USB1PHYCLKMUX) ? 1 : 0;
+}
+
+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_cfgchip_register_usb1_clk48 - Register a new USB 1.1 PHY clock
+ * @regmap: The CFGCHIP regmap
+ */
+struct clk *da8xx_cfgchip_register_usb1_clk48(struct regmap *regmap)
+{
+ const char * const parent_names[] = { "usb0_clk48", "usb_refclkin" };
+ 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 = "usb1_clk48";
+ 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 of_da8xx_usb_phy_clk_init(struct device_node *np)
+{
+ struct clk_onecell_data *clk_data;
+ struct regmap *regmap;
+ struct clk *fck_clk, *clk;
+
+ regmap = syscon_node_to_regmap(of_get_parent(np));
+ if (IS_ERR(regmap)) {
+ pr_err("No regmap for syscon parent (%ld)", PTR_ERR(regmap));
+ return;
+ }
+
+ fck_clk = of_clk_get_by_name(np, "fck");
+ if (IS_ERR(fck_clk)) {
+ pr_err("Missing fck clock (%ld)", PTR_ERR(fck_clk));
+ return;
+ }
+
+ clk_data = clk_alloc_onecell_data(2);
+ if (!clk_data) {
+ clk_put(fck_clk);
+ return;
+ }
+
+ clk = da8xx_cfgchip_register_usb0_clk48(regmap, fck_clk);
+ if (IS_ERR(clk)) {
+ pr_warn("Failed to register usb0_clk48 (%ld)", PTR_ERR(clk));
+ clk_put(fck_clk);
+ } else {
+ clk_data->clks[0] = clk;
+ }
+
+ clk = da8xx_cfgchip_register_usb1_clk48(regmap);
+ if (IS_ERR(clk))
+ pr_warn("Failed to register usb1_clk48 (%ld)", PTR_ERR(clk));
+ else
+ clk_data->clks[1] = clk;
+
+ of_clk_add_provider(np, of_clk_src_onecell_get, clk_data);
+}
+
+CLK_OF_DECLARE(da8xx_usb_phy_clk, "ti,da830-usb-phy-clocks",
+ of_da8xx_usb_phy_clk_init);
+#endif
diff --git a/include/linux/clk/davinci.h b/include/linux/clk/davinci.h
index 54ea3ff..04b48b3 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);
@@ -27,5 +30,8 @@ struct clk *da8xx_cfgchip_register_tbclk(struct regmap *regmap);
struct clk *da8xx_cfgchip_register_div4p5(struct regmap *regmap);
struct clk *da8xx_cfgchip_register_async1(struct regmap *regmap);
struct clk *da8xx_cfgchip_register_async3(struct regmap *regmap);
+struct clk *da8xx_cfgchip_register_usb0_clk48(struct regmap *regmap,
+ struct clk *usb0_psc_clk);
+struct clk *da8xx_cfgchip_register_usb1_clk48(struct regmap *regmap);

#endif /* __LINUX_CLK_DAVINCI_H__ */
--
2.7.4
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