[PATCH v5] clk: add CS2000 Fractional-N driver

From: Kuninori Morimoto
Date: Mon Oct 19 2015 - 21:27:17 EST


From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>

This patch adds CS2000 Fractional-N driver as clock provider.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
v4 -> v5

- remove "clock-frequency"
- use dev on clk_register()
- remove CLK_IS_BASIC
- .enable -> .prepare since it is using I2C
. .disabe -> .unprepare since it is using I2C

.../devicetree/bindings/clock/cs2000-cp.txt | 22 +
drivers/clk/Kconfig | 6 +
drivers/clk/Makefile | 1 +
drivers/clk/clk-cs2000-cp.c | 510 +++++++++++++++++++++
4 files changed, 539 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/cs2000-cp.txt
create mode 100644 drivers/clk/clk-cs2000-cp.c

diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
new file mode 100644
index 0000000..54e6df0
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
@@ -0,0 +1,22 @@
+CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
+
+Required properties:
+
+- compatible: "cirrus,cs2000-cp"
+- reg: The chip select number on the I2C bus
+- clocks: common clock binding for CLK_IN, XTI/REF_CLK
+- clock-names: CLK_IN : clk_in, XTI/REF_CLK : ref_clk
+- #clock-cells: must be <0>
+
+Example:
+
+&i2c2 {
+ ...
+ cs2000: clk_multiplier@4f {
+ #clock-cells = <0>;
+ compatible = "cirrus,cs2000-cp";
+ reg = <0x4f>;
+ clocks = <&rcar_sound 0>, <&x12_clk>;
+ clock-names = "clk_in", "ref_clk";
+ };
+};
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 42f7120..0e961b2 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -95,6 +95,12 @@ config COMMON_CLK_CDCE925
Given a target output frequency, the driver will set the PLL and
divider to best approximate the desired output.

+config COMMON_CLK_CS2000_CP
+ tristate "Clock driver for CS2000 Fractional-N Clock Synthesizer & Clock Multiplier"
+ depends on I2C
+ help
+ If you say yes here you get support for the CS2000 clock multiplier.
+
config COMMON_CLK_S2MPS11
tristate "Clock driver for S2MPS1X/S5M8767 MFD"
depends on MFD_SEC_CORE
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 9d31e2c..2fb77a8 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o
obj-$(CONFIG_ARCH_AXXIA) += clk-axm5516.o
obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
obj-$(CONFIG_COMMON_CLK_CDCE706) += clk-cdce706.o
+obj-$(CONFIG_COMMON_CLK_CS2000_CP) += clk-cs2000-cp.o
obj-$(CONFIG_ARCH_CLPS711X) += clk-clps711x.o
obj-$(CONFIG_ARCH_EFM32) += clk-efm32gg.o
obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
diff --git a/drivers/clk/clk-cs2000-cp.c b/drivers/clk/clk-cs2000-cp.c
new file mode 100644
index 0000000..71d9340
--- /dev/null
+++ b/drivers/clk/clk-cs2000-cp.c
@@ -0,0 +1,510 @@
+/*
+ * CS2000 -- CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
+ *
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ * Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/i2c.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+
+#define CH_MAX 4
+
+#define DEVICE_ID 0x1
+#define DEVICE_CTRL 0x2
+#define DEVICE_CFG1 0x3
+#define DEVICE_CFG2 0x4
+#define GLOBAL_CFG 0x5
+#define Ratio_Add(x, nth) (6 + (x * 4) + (nth))
+#define Ratio_Val(x, nth) ((x >> (24 - (8 * nth))) & 0xFF)
+#define Val_Ratio(x, nth) ((x & 0xFF) << (24 - (8 * nth)))
+#define FUNC_CFG1 0x16
+#define FUNC_CFG2 0x17
+
+/* DEVICE_CTRL */
+#define PLL_UNLOCK (1 << 7)
+
+/* DEVICE_CFG1 */
+#define RSEL(x) (((x) & 0x3) << 3)
+#define RSEL_MASK RSEL(0x3)
+#define ENDEV1 (0x1)
+
+/* GLOBAL_CFG */
+#define ENDEV2 (0x1)
+
+#define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
+#define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
+#define priv_to_client(priv) (priv->client)
+#define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
+
+#define CLK_IN 0
+#define REF_CLK 1
+#define CLK_MAX 2
+
+struct cs2000_priv {
+ struct clk_hw hw;
+ struct i2c_client *client;
+ struct clk *clk_in;
+ struct clk *ref_clk;
+ struct clk *clk_out;
+};
+
+static const struct of_device_id cs2000_of_match[] = {
+ { .compatible = "cirrus,cs2000-cp", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, cs2000_of_match);
+
+static const struct i2c_device_id cs2000_id[] = {
+ { "cs2000-cp", },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, cs2000_id);
+
+#define cs2000_read(priv, addr) \
+ i2c_smbus_read_byte_data(priv_to_client(priv), addr)
+#define cs2000_write(priv, addr, val) \
+ i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
+
+static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
+{
+ s32 data;
+
+ data = cs2000_read(priv, addr);
+ if (data < 0)
+ return data;
+
+ data &= ~mask;
+ data |= (val & mask);
+
+ return cs2000_write(priv, addr, data);
+}
+
+static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
+{
+ u32 val;
+ int ret;
+
+ val = enable ? ENDEV1 : 0;
+ ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1, val);
+ if (ret < 0)
+ return ret;
+
+ val = enable ? ENDEV2 : 0;
+ ret = cs2000_bset(priv, GLOBAL_CFG, ENDEV2, val);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
+ u32 rate_in)
+{
+ u32 val;
+
+ if (rate_in >= 32000000 &&
+ rate_in < 56000000)
+ val = 0x0;
+ else if (rate_in >= 16000000 &&
+ rate_in < 28000000)
+ val = 0x1;
+ else if (rate_in >= 8000000 &&
+ rate_in < 14000000)
+ val = 0x2;
+ else
+ return -EINVAL;
+
+ return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
+}
+
+static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
+{
+ struct device *dev = priv_to_dev(priv);
+ s32 val;
+ unsigned int i;
+
+ for (i = 0; i < 256; i++) {
+ val = cs2000_read(priv, DEVICE_CTRL);
+ if (val < 0)
+ return val;
+ if (!(val & PLL_UNLOCK))
+ return 0;
+ udelay(1);
+ }
+
+ dev_err(dev, "pll lock failed\n");
+
+ return -EIO;
+}
+
+static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
+{
+ u32 val = enable ? 0 : 0x3;
+
+ /* enable both AUX_OUT, CLK_OUT */
+ return cs2000_write(priv, DEVICE_CTRL, val);
+}
+
+static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
+{
+ u64 ratio;
+
+ /*
+ * ratio = rate_out / rate_in * 2^20
+ *
+ * To avoid over flow, rate_out is u64
+ * The result should be u32
+ */
+ ratio = (u64)rate_out << 20;
+ do_div(ratio, rate_in);
+
+ return (u32)ratio;
+}
+
+static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
+{
+ u64 rate_out;
+
+ /*
+ * ratio = rate_out / rate_in * 2^20
+ *
+ * To avoid over flow, rate_out is u64
+ * The result should be u32
+ */
+
+ rate_out = (u64)ratio * rate_in;
+ return (unsigned long)(rate_out >> 20);
+}
+
+static int cs2000_ratio_set(struct cs2000_priv *priv,
+ int ch, u32 rate_in, u32 rate_out)
+{
+ u32 val;
+ unsigned int i;
+ int ret;
+
+ if (CH_SIZE_ERR(ch))
+ return -EINVAL;
+
+ val = cs2000_rate_to_ratio(rate_in, rate_out);
+ for (i = 0; i < 4; i++) {
+ ret = cs2000_write(priv,
+ Ratio_Add(ch, i),
+ Ratio_Val(val, i));
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
+{
+ u32 tmp, val;
+ unsigned int i;
+
+ val = 0;
+ for (i = 0; i < 4; i++) {
+ tmp = cs2000_read(priv,
+ Ratio_Add(ch, i));
+ if (tmp < 0)
+ return 0;
+
+ val |= Val_Ratio(tmp, i);
+ }
+
+ return val;
+}
+
+static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
+{
+ int ret;
+
+ if (CH_SIZE_ERR(ch))
+ return -EINVAL;
+
+ /*
+ * FIXME
+ *
+ * this driver supports static ratio mode only
+ * at this point
+ */
+ ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct cs2000_priv *priv = hw_to_priv(hw);
+ int ch = 0; /* it uses ch0 only at this point */
+ u32 ratio;
+
+ ratio = cs2000_ratio_get(priv, ch);
+
+ return cs2000_ratio_to_rate(ratio, parent_rate);
+}
+
+static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ u32 ratio;
+
+ ratio = cs2000_rate_to_ratio(*parent_rate, rate);
+
+ return cs2000_ratio_to_rate(ratio, *parent_rate);
+}
+
+static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
+ unsigned long rate, unsigned long parent_rate)
+
+{
+ int ret;
+
+ ret = cs2000_clk_in_bound_rate(priv, parent_rate);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_ratio_select(priv, ch);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int cs2000_set_rate(struct clk_hw *hw,
+ unsigned long rate, unsigned long parent_rate)
+{
+ struct cs2000_priv *priv = hw_to_priv(hw);
+ int ch = 0; /* it uses ch0 only at this point */
+
+ return __cs2000_set_rate(priv, ch, rate, parent_rate);
+}
+
+static int cs2000_enable(struct clk_hw *hw)
+{
+ struct cs2000_priv *priv = hw_to_priv(hw);
+ int ret;
+
+ ret = cs2000_enable_dev_config(priv, true);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_clk_out_enable(priv, true);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_wait_pll_lock(priv);
+ if (ret < 0)
+ return ret;
+
+ return ret;
+}
+
+static void cs2000_disable(struct clk_hw *hw)
+{
+ struct cs2000_priv *priv = hw_to_priv(hw);
+
+ cs2000_enable_dev_config(priv, false);
+
+ cs2000_clk_out_enable(priv, false);
+}
+
+static u8 cs2000_get_parent(struct clk_hw *hw)
+{
+ /* always return REF_CLK */
+ return REF_CLK;
+}
+
+static const struct clk_ops cs2000_ops = {
+ .get_parent = cs2000_get_parent,
+ .recalc_rate = cs2000_recalc_rate,
+ .round_rate = cs2000_round_rate,
+ .set_rate = cs2000_set_rate,
+ .prepare = cs2000_enable,
+ .unprepare = cs2000_disable,
+};
+
+static int cs2000_clk_get(struct cs2000_priv *priv)
+{
+ struct i2c_client *client = priv_to_client(priv);
+ struct device *dev = &client->dev;
+ struct clk *clk_in, *ref_clk;
+
+ clk_in = devm_clk_get(dev, "clk_in");
+ /* not yet provided */
+ if (IS_ERR(clk_in))
+ return -EPROBE_DEFER;
+
+ ref_clk = devm_clk_get(dev, "ref_clk");
+ /* not yet provided */
+ if (IS_ERR(ref_clk))
+ return -EPROBE_DEFER;
+
+ priv->clk_in = clk_in;
+ priv->ref_clk = ref_clk;
+
+ return 0;
+}
+
+static int cs2000_clk_register(struct cs2000_priv *priv)
+{
+ struct device *dev = priv_to_dev(priv);
+ struct device_node *np = dev->of_node;
+ struct clk_init_data init;
+ const char *name = np->name;
+ struct clk *clk;
+ static const char *parent_names[CLK_MAX];
+ int ch = 0; /* it uses ch0 only at this point */
+ int rate;
+ int ret;
+
+ of_property_read_string(np, "clock-output-names", &name);
+
+ /*
+ * set default rate as 1/1.
+ * otherwise .set_rate which setup ratio
+ * is never called if user requests 1/1 rate
+ */
+ rate = clk_get_rate(priv->ref_clk);
+ ret = __cs2000_set_rate(priv, ch, rate, rate);
+ if (ret < 0)
+ return ret;
+
+ parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
+ parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
+
+ init.name = name;
+ init.ops = &cs2000_ops;
+ init.flags = CLK_SET_RATE_GATE;
+ init.parent_names = parent_names;
+ init.num_parents = ARRAY_SIZE(parent_names);
+
+ priv->hw.init = &init;
+
+ clk = clk_register(dev, &priv->hw);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+ if (ret < 0) {
+ clk_unregister(clk);
+ return ret;
+ }
+
+ priv->clk_out = clk;
+
+ return 0;
+}
+
+static int cs2000_version_print(struct cs2000_priv *priv)
+{
+ struct i2c_client *client = priv_to_client(priv);
+ struct device *dev = &client->dev;
+ s32 val = cs2000_read(priv, DEVICE_ID);
+ const char *revision;
+
+ if (val < 0)
+ return val;
+
+ /* CS2000 should be 0x0 */
+ if (0 != (val >> 3))
+ return -EIO;
+
+ switch (val & 0x7) {
+ case 0x4:
+ revision = "B2 / B3";
+ break;
+ case 0x6:
+ revision = "C1";
+ break;
+ default:
+ return -EIO;
+ }
+
+ dev_info(dev, "revision - %s\n", revision);
+
+ return 0;
+}
+
+static int cs2000_remove(struct i2c_client *client)
+{
+ struct cs2000_priv *priv = i2c_get_clientdata(client);
+ struct device *dev = &client->dev;
+ struct device_node *np = dev->of_node;
+
+ of_clk_del_provider(np);
+
+ clk_unregister(priv->clk_out);
+
+ return 0;
+}
+
+static int cs2000_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct cs2000_priv *priv;
+ struct device *dev = &client->dev;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->client = client;
+ i2c_set_clientdata(client, priv);
+
+ ret = cs2000_clk_get(priv);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_clk_register(priv);
+ if (ret < 0)
+ return ret;
+
+ ret = cs2000_version_print(priv);
+ if (ret < 0)
+ goto probe_err;
+
+ return 0;
+
+probe_err:
+ cs2000_remove(client);
+
+ return ret;
+}
+
+static struct i2c_driver cs2000_driver = {
+ .driver = {
+ .name = "cs2000-cp",
+ .of_match_table = cs2000_of_match,
+ },
+ .probe = cs2000_probe,
+ .remove = cs2000_remove,
+ .id_table = cs2000_id,
+};
+
+module_i2c_driver(cs2000_driver);
+
+MODULE_DESCRIPTION("CS2000-CP driver");
+MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
--
1.9.1

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