clk: add CS2000 Fractional-N driver

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

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[sboyd@codeaurora.org: Fix unsigned checked for < 0 in
cs2000_ratio_get()]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

diff --git a/Documentation/devicetree/bindings/clock/cs2000-cp.txt b/Documentation/devicetree/bindings/clock/cs2000-cp.txt
new file mode 100644 (file)
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 c3e3a02f7f1f9b288ac93a524db3615f6abb72ae..d2d3871e64c928ff7e683b628acd5266a5c2f30a 100644 (file)
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -116,6 +116,12 @@ 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 f4165bb9a270efd8243c7d3de99e757a4e9054c6..0ecccf30cd28302bca61052eb84ae4d37e568c76 100644 (file)
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_MACH_ASM9260)            += clk-asm9260.o
 obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)    += clk-axi-clkgen.o
 obj-$(CONFIG_ARCH_AXXIA)               += clk-axm5516.o
 obj-$(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 (file)
index 0000000..7379de8
--- /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@renesas.com>
+ *
+ * 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 RATIO_REG_SIZE 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_ID */
+#define REVISION_MASK  (0x7)
+#define REVISION_B2_B3 (0x4)
+#define REVISION_C1    (0x6)
+
+/* 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)
+{
+       int ret;
+
+       ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
+                         enable ? ENDEV1 : 0);
+       if (ret < 0)
+               return ret;
+
+       ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2,
+                         enable ? ENDEV2 : 0);
+       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 -ETIMEDOUT;
+}
+
+static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
+{
+       /* enable both AUX_OUT, CLK_OUT */
+       return cs2000_write(priv, DEVICE_CTRL, enable ? 0 : 0x3);
+}
+
+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 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 or unsigned long.
+        */
+
+       rate_out = (u64)ratio * rate_in;
+       return 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 < RATIO_REG_SIZE; 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)
+{
+       s32 tmp;
+       u32 val;
+       unsigned int i;
+
+       val = 0;
+       for (i = 0; i < RATIO_REG_SIZE; 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;
+       const char *revision;
+
+       val = cs2000_read(priv, DEVICE_ID);
+       if (val < 0)
+               return val;
+
+       /* CS2000 should be 0x0 */
+       if (val >> 3)
+               return -EIO;
+
+       switch (val & REVISION_MASK) {
+       case REVISION_B2_B3:
+               revision = "B2 / B3";
+               break;
+       case REVISION_C1:
+               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@renesas.com>");
+MODULE_LICENSE("GPL v2");