clk: hi6220: Add the hi655x's pmic clock

The hi655x multi function device is a PMIC providing regulators.

The PMIC also provides a clock for the WiFi and the Bluetooth, let's implement
this clock in order to add it in the hi655x MFD and allow proper wireless
initialization.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
[sboyd@codeaurora.org: Remove clkdev usage]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

3 files changed, 135 insertions, 0 deletions

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 9356ab4b7d76..36cfea38135f 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -47,6 +47,14 @@ config COMMON_CLK_RK808
           clocked at 32KHz each. Clkout1 is always on, Clkout2 can off
           by control register.
 
+config COMMON_CLK_HI655X
+        tristate "Clock driver for Hi655x"
+        depends on MFD_HI655X_PMIC || COMPILE_TEST
+        ---help---
+          This driver supports the hi655x PMIC clock. This
+          multi-function device has one fixed-rate oscillator, clocked
+          at 32KHz.
+
 config COMMON_CLK_SCPI
         tristate "Clock driver controlled via SCPI interface"
         depends on ARM_SCPI_PROTOCOL || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 92c12b86c2e8..c19983afcb81 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_COMMON_CLK_PALMAS)		+= clk-palmas.o
 obj-$(CONFIG_COMMON_CLK_PWM)            += clk-pwm.o
 obj-$(CONFIG_CLK_QORIQ)                 += clk-qoriq.o
 obj-$(CONFIG_COMMON_CLK_RK808)          += clk-rk808.o
+obj-$(CONFIG_COMMON_CLK_HI655X)         += clk-hi655x.o
 obj-$(CONFIG_COMMON_CLK_S2MPS11)        += clk-s2mps11.o
 obj-$(CONFIG_COMMON_CLK_SCPI)           += clk-scpi.o
 obj-$(CONFIG_COMMON_CLK_SI5351)         += clk-si5351.o
diff --git a/drivers/clk/clk-hi655x.c b/drivers/clk/clk-hi655x.c
new file mode 100644
index 000000000000..403a0188634a
--- /dev/null
+++ b/drivers/clk/clk-hi655x.c
@@ -0,0 +1,126 @@
+/*
+ * Clock driver for Hi655x
+ *
+ * Copyright (c) 2017, Linaro Ltd.
+ *
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/hi655x-pmic.h>
+
+#define HI655X_CLK_BASE HI655X_BUS_ADDR(0x1c)
+#define HI655X_CLK_SET  BIT(6)
+
+struct hi655x_clk {
+        struct hi655x_pmic *hi655x;
+        struct clk_hw       clk_hw;
+};
+
+static unsigned long hi655x_clk_recalc_rate(struct clk_hw *hw,
+                                            unsigned long parent_rate)
+{
+        return 32768;
+}
+
+static int hi655x_clk_enable(struct clk_hw *hw, bool enable)
+{
+        struct hi655x_clk *hi655x_clk =
+                container_of(hw, struct hi655x_clk, clk_hw);
+
+        struct hi655x_pmic *hi655x = hi655x_clk->hi655x;
+
+        return regmap_update_bits(hi655x->regmap, HI655X_CLK_BASE,
+                                  HI655X_CLK_SET, enable ? HI655X_CLK_SET : 0);
+}
+
+static int hi655x_clk_prepare(struct clk_hw *hw)
+{
+        return hi655x_clk_enable(hw, true);
+}
+
+static void hi655x_clk_unprepare(struct clk_hw *hw)
+{
+        hi655x_clk_enable(hw, false);
+}
+
+static int hi655x_clk_is_prepared(struct clk_hw *hw)
+{
+        struct hi655x_clk *hi655x_clk =
+                container_of(hw, struct hi655x_clk, clk_hw);
+        struct hi655x_pmic *hi655x = hi655x_clk->hi655x;
+        int ret;
+        uint32_t val;
+
+        ret = regmap_read(hi655x->regmap, HI655X_CLK_BASE, &val);
+        if (ret < 0)
+                return ret;
+
+        return val & HI655X_CLK_BASE;
+}
+
+static const struct clk_ops hi655x_clk_ops = {
+        .prepare     = hi655x_clk_prepare,
+        .unprepare   = hi655x_clk_unprepare,
+        .is_prepared = hi655x_clk_is_prepared,
+        .recalc_rate = hi655x_clk_recalc_rate,
+};
+
+static int hi655x_clk_probe(struct platform_device *pdev)
+{
+        struct device *parent = pdev->dev.parent;
+        struct hi655x_pmic *hi655x = dev_get_drvdata(parent);
+        struct hi655x_clk *hi655x_clk;
+        const char *clk_name = "hi655x-clk";
+        struct clk_init_data init = {
+                .name = clk_name,
+                .ops = &hi655x_clk_ops
+        };
+        int ret;
+
+        hi655x_clk = devm_kzalloc(&pdev->dev, sizeof(*hi655x_clk), GFP_KERNEL);
+        if (!hi655x_clk)
+                return -ENOMEM;
+
+        of_property_read_string_index(parent->of_node, "clock-output-names",
+                                      0, &clk_name);
+
+        hi655x_clk->clk_hw.init = &init;
+        hi655x_clk->hi655x      = hi655x;
+
+        platform_set_drvdata(pdev, hi655x_clk);
+
+        ret = devm_clk_hw_register(&pdev->dev, &hi655x_clk->clk_hw);
+        if (ret)
+                return ret;
+
+        return of_clk_add_hw_provider(parent->of_node, of_clk_hw_simple_get,
+                                     &hi655x_clk->clk_hw);
+}
+
+static struct platform_driver hi655x_clk_driver = {
+        .probe =  hi655x_clk_probe,
+        .driver         = {
+                .name   = "hi655x-clk",
+        },
+};
+
+module_platform_driver(hi655x_clk_driver);
+
+MODULE_DESCRIPTION("Clk driver for the hi655x series PMICs");
+MODULE_AUTHOR("Daniel Lezcano <daniel.lezcano@linaro.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:hi655x-clk");