[PATCH V3 1/2] clk: hi6220: Add the hi655x's pmic clock

[Daniel Lezcano]

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@xxxxxxxxxx>
---

Changelog:

 V3:
    - Removed mfd hi655x fold from V2
    - Fixed #clock-cells
    - Used struct clk_init_data on the stack
    - Swapped lookup name for devm_clk_hw_register
 V2:
    - Added COMPILE_TEST option, compiled on x86
    - Removed useless parenthesis
    - Used of_clk_hw_simple_get() instead of deref dance
    - Do bailout if the clock-names is not specified
    - Rollback on error
    - Folded mfd line change and binding
    - Added #clock-cells binding documentation
    - Added #clock-cells in the DT

 V1: initial post
---
 drivers/clk/Kconfig      |   8 +++
 drivers/clk/Makefile     |   1 +
 drivers/clk/clk-hi655x.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 145 insertions(+)
 create mode 100644 drivers/clk/clk-hi655x.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 9356ab4..36cfea3 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 92c12b8..c19983a 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 0000000..4384c6f
--- /dev/null
+++ b/drivers/clk/clk-hi655x.c
@@ -0,0 +1,136 @@
+/*
+ * Clock driver for Hi655x
+ *
+ * Copyright (c) 2017, Linaro Ltd.
+ *
+ * Author: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
+ *
+ * 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/clkdev.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;
+
+	ret = of_clk_add_hw_provider(parent->of_node, of_clk_hw_simple_get,
+				     &hi655x_clk->clk_hw);
+	if (ret)
+		return ret;
+
+	ret = clk_hw_register_clkdev(&hi655x_clk->clk_hw, NULL, clk_name);
+	if (ret)
+		of_clk_del_provider(parent->of_node);
+
+	return ret;
+}
+
+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@xxxxxxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:hi655x-clk");
-- 
1.9.1