[PATCH 2/2 v5] clk: Add Gemini SoC clock controller
Linus Walleij
linus.walleij at linaro.org
Mon Jun 5 06:51:09 PDT 2017
The Cortina Systems Gemini (SL3516/CS3516) has an on-chip clock
controller that derive all clocks from a single crystal, using some
documented and some undocumented PLLs, half dividers, counters and
gates. This is a best attempt to construct a clock driver for the
clocks so at least we can gate off unused hardware and driver the
PCI bus clock.
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
Mike/Stephen: please merge this into the clk subsystem along
with the <dt-bindings> patch once you're happy with it.
ChangeLog v4->v5:
- Add a dependency on ARCH_GEMINI || COMPILE_TEST to Kconfig
- Fix the includes, remove <linux/clkdev.h>, add <linux/spinlock.h>
- Indent all defines properly.
- Remove the global clock arrays and use the pattern to allocate
a struct clk_hw_onecell_data * and fill that with the hw clocks.
- Switch everything to use struct clk_hw * everywhere.
- Look up clocks using of_clk_hw_onecell_get, add the lookup
using of_clk_add_hw_provider().
- Cut unnecessary status checks from regmap_* accessors, skip
to just checking the return value of the first access and
then assume the MMIO regmap is working fine.
- Reduce the CPU-to-AHB calculation switch() statement to a table
lookup.
ChangeLog v3->v4:
- No changes, just resending with separate DT header file.
ChangeLog v2->v3:
- Augment driver to probe directly from the system controller.
- Mike/Stephen: when you're happy with this please ACK it so I
can merge it through ARM SoC. This is needed because of
the mess of #include <dt-bindings/*> from the DT bindings
that is then used all over the DTS files.
ChangeLog v1->v2:
- Move the clock controller to be part of the syscon node. No
need for a separate child node for this.
---
drivers/clk/Kconfig | 8 ++
drivers/clk/Makefile | 1 +
drivers/clk/clk-gemini.c | 345 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 354 insertions(+)
create mode 100644 drivers/clk/clk-gemini.c
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 36cfea38135f..be3ca2da628b 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -126,6 +126,14 @@ config COMMON_CLK_CS2000_CP
help
If you say yes here you get support for the CS2000 clock multiplier.
+config COMMON_CLK_GEMINI
+ bool "Clock driver for Cortina Systems Gemini SoC"
+ depends on ARCH_GEMINI || COMPILE_TEST
+ select MFD_SYSCON
+ ---help---
+ This driver supports the SoC clocks on the Cortina Systems Gemini
+ platform, also known as SL3516 or CS3516.
+
config COMMON_CLK_S2MPS11
tristate "Clock driver for S2MPS1X/S5M8767 MFD"
depends on MFD_SEC_CORE || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index c19983afcb81..a625c002a810 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -25,6 +25,7 @@ obj-$(CONFIG_COMMON_CLK_CDCE925) += clk-cdce925.o
obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o
obj-$(CONFIG_COMMON_CLK_CS2000_CP) += clk-cs2000-cp.o
obj-$(CONFIG_ARCH_EFM32) += clk-efm32gg.o
+obj-$(CONFIG_COMMON_CLK_GEMINI) += clk-gemini.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
obj-$(CONFIG_ARCH_MB86S7X) += clk-mb86s7x.o
diff --git a/drivers/clk/clk-gemini.c b/drivers/clk/clk-gemini.c
new file mode 100644
index 000000000000..81937f942489
--- /dev/null
+++ b/drivers/clk/clk-gemini.c
@@ -0,0 +1,345 @@
+/*
+ * Cortina Gemini Clock Controller driver
+ * Copyright (c) 2017 Linus Walleij <linus.walleij at linaro.org>
+ */
+
+#define pr_fmt(fmt) "clk-gemini: " fmt
+
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk-provider.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/spinlock.h>
+#include <dt-bindings/clock/cortina,gemini-clock.h>
+
+/* Globally visible clocks */
+static DEFINE_SPINLOCK(gemini_clk_lock);
+
+#define GEMINI_GLOBAL_STATUS 0x04
+#define PLL_OSC_SEL BIT(30)
+#define AHBSPEED_SHIFT (15)
+#define AHBSPEED_MASK 0x07
+#define CPU_AHB_RATIO_SHIFT (18)
+#define CPU_AHB_RATIO_MASK 0x03
+
+#define GEMINI_GLOBAL_PLL_CONTROL 0x08
+
+#define GEMINI_GLOBAL_MISC_CONTROL 0x30
+#define PCI_CLK_66MHZ BIT(18)
+#define PCI_CLK_OE BIT(17)
+
+#define GEMINI_GLOBAL_CLOCK_CONTROL 0x34
+#define PCI_CLKRUN_EN BIT(16)
+#define TVC_HALFDIV_SHIFT (24)
+#define TVC_HALFDIV_MASK 0x1f
+#define SECURITY_CLK_SEL BIT(29)
+
+#define GEMINI_GLOBAL_PCI_DLL_CONTROL 0x44
+#define PCI_DLL_BYPASS BIT(31)
+#define PCI_DLL_TAP_SEL_MASK 0x1f
+
+/**
+ * struct gemini_data_data - Gemini gated clocks
+ * @bit_idx: the bit used to gate this clock in the clock register
+ * @name: the clock name
+ * @parent_name: the name of the parent clock
+ * @flags: standard clock framework flags
+ */
+struct gemini_gate_data {
+ u8 bit_idx;
+ const char *name;
+ const char *parent_name;
+ unsigned long flags;
+};
+
+/**
+ * struct clk_gemini_pci - Gemini PCI clock
+ * @hw: corresponding clock hardware entry
+ * @map: regmap to access the registers
+ * @rate: current rate
+ */
+struct clk_gemini_pci {
+ struct clk_hw hw;
+ struct regmap *map;
+ unsigned long rate;
+};
+
+/*
+ * FIXME: some clocks are marked as CLK_IGNORE_UNUSED: this is
+ * because their kernel drivers lack proper clock handling so we
+ * need to avoid them being gated off by default. Remove this as
+ * the drivers get fixed to handle clocks properly.
+ *
+ * The DDR controller may never have a driver, but certainly must
+ * not be gated off.
+ */
+static const struct gemini_gate_data gemini_gates[] __initconst = {
+ { 1, "security-gate", "secdiv", 0 },
+ { 2, "gmac0-gate", "ahb", 0 },
+ { 3, "gmac1-gate", "ahb", 0 },
+ { 4, "sata0-gate", "ahb", 0 },
+ { 5, "sata1-gate", "ahb", 0 },
+ { 6, "usb0-gate", "ahb", 0 },
+ { 7, "usb1-gate", "ahb", 0 },
+ { 8, "ide-gate", "ahb", 0 },
+ { 9, "pci-gate", "ahb", 0 },
+ { 10, "ddr-gate", "ahb", CLK_IS_CRITICAL },
+ { 11, "flash-gate", "ahb", CLK_IGNORE_UNUSED },
+ { 12, "tvc-gate", "ahb", 0 },
+ { 13, "boot-gate", "apb", 0 },
+};
+
+#define to_pciclk(_hw) container_of(_hw, struct clk_gemini_pci, hw)
+
+static unsigned long gemini_pci_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+ u32 val;
+
+ regmap_read(pciclk->map, GEMINI_GLOBAL_MISC_CONTROL, &val);
+ if (val & PCI_CLK_66MHZ)
+ return 66000000;
+ return 33000000;
+}
+
+static long gemini_pci_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ /* We support 33 and 66 MHz */
+ if (rate < 48000000)
+ return 33000000;
+ return 66000000;
+}
+
+static int gemini_pci_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ if (rate == 33000000)
+ return regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ PCI_CLK_66MHZ, 0);
+ if (rate == 66000000)
+ return regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ 0, PCI_CLK_66MHZ);
+ return -EINVAL;
+}
+
+static int gemini_pci_enable(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
+ 0, PCI_CLKRUN_EN);
+ regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ 0, PCI_CLK_OE);
+ return 0;
+}
+
+static void gemini_pci_disable(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+
+ regmap_update_bits(pciclk->map,
+ GEMINI_GLOBAL_MISC_CONTROL,
+ PCI_CLK_OE, 0);
+ regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
+ PCI_CLKRUN_EN, 0);
+}
+
+static int gemini_pci_is_enabled(struct clk_hw *hw)
+{
+ struct clk_gemini_pci *pciclk = to_pciclk(hw);
+ unsigned int val;
+
+ regmap_read(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
+ return !!(val & PCI_CLKRUN_EN);
+}
+
+static const struct clk_ops gemini_pci_clk_ops = {
+ .recalc_rate = gemini_pci_recalc_rate,
+ .round_rate = gemini_pci_round_rate,
+ .set_rate = gemini_pci_set_rate,
+ .enable = gemini_pci_enable,
+ .disable = gemini_pci_disable,
+ .is_enabled = gemini_pci_is_enabled,
+};
+
+static struct clk_hw * __init gemini_pci_clk_setup(const char *name,
+ const char *parent_name,
+ struct regmap *map)
+{
+ struct clk_gemini_pci *pciclk;
+ struct clk_init_data init;
+ int ret;
+
+ pciclk = kzalloc(sizeof(*pciclk), GFP_KERNEL);
+ if (!pciclk)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &gemini_pci_clk_ops;
+ init.flags = 0;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ pciclk->map = map;
+ pciclk->hw.init = &init;
+
+ ret = clk_hw_register(NULL, &pciclk->hw);
+ if (ret) {
+ kfree(pciclk);
+ return ERR_PTR(ret);
+ }
+
+ return &pciclk->hw;
+}
+
+static void __init gemini_cc_init(struct device_node *np)
+{
+ /* Gives the fracions 1x, 1.5x, 1.85x and 2x */
+ unsigned int cpu_ahb_mult[4] = { 1, 3, 24, 2 };
+ unsigned int cpu_ahb_div[4] = { 1, 2, 13, 1 };
+ void __iomem *base;
+ struct regmap *map;
+ struct clk_hw *hw;
+ struct clk_hw_onecell_data *clk_data;
+ unsigned int mult, div;
+ unsigned long freq;
+ u32 val;
+ int ret;
+ int i;
+
+ /* FIXME devm_ if we can make it a platform device */
+ clk_data = kzalloc(sizeof(*clk_data) +
+ sizeof(*clk_data->hws) * GEMINI_NUM_CLKS,
+ GFP_KERNEL);
+ if (!clk_data) {
+ pr_err("out of memory for clocks\n");
+ return;
+ }
+
+ /* Remap the system controller for the exclusive register */
+ base = of_iomap(np, 0);
+ if (!base) {
+ pr_err("no memory base\n");
+ return;
+ }
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ pr_err("no syscon regmap\n");
+ return;
+ }
+
+ /* RTC clock 32768 Hz */
+ hw = clk_hw_register_fixed_rate(NULL, "rtc", NULL, 0, 32768);
+ clk_data->hws[GEMINI_CLK_RTC] = hw;
+
+ /*
+ * We check that the regmap works on this very first access,
+ * but as this is an MMIO-backed regmap, subsequent regmap
+ * access is not going to fail and we skip error checks from
+ * this point.
+ */
+ ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
+ if (ret) {
+ pr_err("failed to read global status register\n");
+ return;
+ }
+
+ /*
+ * XTAL is the crystal oscillator, 60 or 30 MHz selected from
+ * strap pin E6
+ */
+ if (val & PLL_OSC_SEL)
+ freq = 30000000;
+ else
+ freq = 60000000;
+ hw = clk_hw_register_fixed_rate(NULL, "xtal", NULL, 0, freq);
+ pr_info("main crystal @%lu MHz\n", (freq / 1000000));
+
+ /* VCO clock derived from the crystal */
+ mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK);
+ div = 2;
+ /* If we run on 30 MHz crystal we have to multiply with two */
+ if (val & PLL_OSC_SEL)
+ mult *= 2;
+ hw = clk_hw_register_fixed_factor(NULL, "vco", "xtal", 0, mult, div);
+
+ /* The AHB clock is always 1/3 of the VCO */
+ hw = clk_hw_register_fixed_factor(NULL, "ahb", "vco", 0, 1, 3);
+ clk_data->hws[GEMINI_CLK_AHB] = hw;
+
+ /* The APB clock is always 1/6 of the AHB */
+ hw = clk_hw_register_fixed_factor(NULL, "apb", "ahb", 0, 1, 6);
+ clk_data->hws[GEMINI_CLK_APB] = hw;
+
+ /* CPU clock derived as a fixed ratio from the AHB clock */
+ val >>= CPU_AHB_RATIO_SHIFT;
+ val &= CPU_AHB_RATIO_MASK;
+ hw = clk_hw_register_fixed_factor(NULL, "cpu", "ahb", 0,
+ cpu_ahb_mult[val],
+ cpu_ahb_div[val]);
+ clk_data->hws[GEMINI_CLK_CPU] = hw;
+
+ /* Security clock is 1:1 or 0.75 of APB */
+ regmap_read(map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
+ if (val & SECURITY_CLK_SEL) {
+ mult = 1;
+ div = 1;
+ } else {
+ mult = 3;
+ div = 4;
+ }
+ hw = clk_hw_register_fixed_factor(NULL, "secdiv", "ahb", 0, mult, div);
+
+ /*
+ * These are the leaf gates, at boot no clocks are gated.
+ */
+ for (i = 0; i < ARRAY_SIZE(gemini_gates); i++) {
+ const struct gemini_gate_data *gd;
+
+ gd = &gemini_gates[i];
+ clk_data->hws[GEMINI_CLK_GATES + i] =
+ clk_hw_register_gate(NULL, gd->name,
+ gd->parent_name,
+ gd->flags,
+ base + GEMINI_GLOBAL_CLOCK_CONTROL,
+ gd->bit_idx,
+ CLK_GATE_SET_TO_DISABLE,
+ &gemini_clk_lock);
+ }
+
+ /*
+ * The TV Interface Controller has a 5-bit half divider register.
+ * This clock is supposed to be 27MHz as this is an exact multiple
+ * of PAL and NTSC frequencies. The register is undocumented :(
+ * FIXME: figure out the parent and how the divider works.
+ */
+ mult = 1;
+ div = ((val >> TVC_HALFDIV_SHIFT) & TVC_HALFDIV_MASK);
+ pr_debug("TVC half divider value = %d\n", div);
+ div += 1;
+ hw = clk_hw_register_fixed_rate(NULL, "tvcdiv", "xtal", 0, 27000000);
+ clk_data->hws[GEMINI_CLK_TVC] = hw;
+
+ /* FIXME: very unclear what the parent is */
+ hw = gemini_pci_clk_setup("PCI", "xtal", map);
+ clk_data->hws[GEMINI_CLK_PCI] = hw;
+
+ /* FIXME: very unclear what the parent is */
+ hw = clk_hw_register_fixed_rate(NULL, "uart", "xtal", 0, 48000000);
+ clk_data->hws[GEMINI_CLK_UART] = hw;
+
+ /* Register the clocks to be accessed by the device tree */
+ clk_data->num = GEMINI_NUM_CLKS;
+ of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_data);
+}
+CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);
--
2.9.4
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