[PATCH v2 08/10] clk: Add driver for Maxim 77802 PMIC clocks

Javier Martinez Canillas
2014-06-16T18:09:10Z

The MAX77802 PMIC has two 32.768kHz Buffered Clock Outputs with
Low Jitter Mode. This patch adds support for these two clocks.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---

Changes since v1:
- Use module_platform_driver() instead of having init/exit functions.
Suggested by Mark Brown.
- Use the generic maxim clock driver to reduce code duplication with
clk-max77686.c driver.

.../devicetree/bindings/clock/maxim,max77802.txt | 42 +++++++++
drivers/clk/Kconfig | 7 ++
drivers/clk/Makefile | 1 +
drivers/clk/clk-max77802.c | 99 ++++++++++++++++++++++
drivers/mfd/max77802.c | 1 +
include/dt-bindings/clock/maxim,max77802.h | 22 +++++
6 files changed, 172 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/maxim,max77802.txt
create mode 100644 drivers/clk/clk-max77802.c
create mode 100644 include/dt-bindings/clock/maxim,max77802.h

diff --git a/Documentation/devicetree/bindings/clock/maxim,max77802.txt b/Documentation/devicetree/bindings/clock/maxim,max77802.txt
new file mode 100644
index 0000000..b2c2129
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/maxim,max77802.txt
@@ -0,0 +1,42 @@
+Binding for Maxim MAX77802 32k clock generator block
+
+This is a part of device tree bindings of MAX77802 multi-function device.
+More information can be found in bindings/mfd/max77802.txt file.
+
+The MAX77802 contains two 32.768khz clock outputs that can be controlled
+(gated/ungated) over I2C.
+
+Following properties should be presend in main device node of the MFD chip.
+
+Required properties:
+
+- #clock-cells: from common clock binding; shall be set to 1.
+
+Each clock is assigned an identifier and client nodes can use this identifier
+to specify the clock which they consume. Following indices are allowed:
+ - 0: 32khz_ap clock,
+ - 1: 32khz_cp clock.
+
+Clocks are defined as preprocessor macros in dt-bindings/clock/maxim,max77802.h
+header and can be used in device tree sources.
+
+Example: Node of the MFD chip
+
+ max77802: max77802@09 {
+ compatible = "maxim,max77802";
+ interrupt-parent = <&wakeup_eint>;
+ interrupts = <26 0>;
+ reg = <0x09>;
+ #clock-cells = <1>;
+
+ /* ... */
+ };
+
+Example: Clock consumer node
+
+ foo@0 {
+ compatible = "bar,foo";
+ /* ... */
+ clock-names = "32khz_ap";
+ clocks = <&max77802 MAX77802_CLK_32K_AP>;
+ };
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 3fd4270..221260b 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -42,6 +42,13 @@ config COMMON_CLK_MAX77686
---help---
This driver supports Maxim 77686 crystal oscillator clock.

+config COMMON_CLK_MAX77802
+ tristate "Clock driver for Maxim 77802 MFD"
+ depends on MFD_MAX77802
+ select COMMON_CLK_MAX_GEN
+ ---help---
+ This driver supports Maxim 77802 crystal oscillator clock.
+
config COMMON_CLK_SI5351
tristate "Clock driver for SiLabs 5351A/B/C"
depends on I2C
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 6c1aff6..520ff76 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_ARCH_HIGHBANK) += clk-highbank.o
obj-$(CONFIG_MACH_LOONGSON1) += clk-ls1x.o
obj-$(CONFIG_COMMON_CLK_MAX_GEN) += clk-max-gen.o
obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o
+obj-$(CONFIG_COMMON_CLK_MAX77802) += clk-max77802.o
obj-$(CONFIG_ARCH_MOXART) += clk-moxart.o
obj-$(CONFIG_ARCH_NOMADIK) += clk-nomadik.o
obj-$(CONFIG_ARCH_NSPIRE) += clk-nspire.o
diff --git a/drivers/clk/clk-max77802.c b/drivers/clk/clk-max77802.c
new file mode 100644
index 0000000..4253b44
--- /dev/null
+++ b/drivers/clk/clk-max77802.c
@@ -0,0 +1,99 @@
+/*
+ * clk-max77802.c - Clock driver for Maxim 77802
+ *
+ * Copyright (C) 2014 Google, Inc
+ *
+ * Copyright (C) 2012 Samsung Electornics
+ * Jonghwa Lee <jonghwa3.lee@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * This driver is based on clk-max77686.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/max77802.h>
+#include <linux/mfd/max77802-private.h>
+#include <linux/clk-provider.h>
+#include <linux/mutex.h>
+#include <linux/clkdev.h>
+
+#include <dt-bindings/clock/maxim,max77802.h>
+#include "clk-max-gen.h"
+
+#define MAX77802_CLOCK_OPMODE_MASK 0x1
+#define MAX77802_CLOCK_LOW_JITTER_SHIFT 0x3
+
+static struct clk_init_data max77802_clks_init[MAX77802_CLKS_NUM] = {
+ [MAX77802_CLK_32K_AP] = {
+ .name = "32khz_ap",
+ .ops = &max_gen_clk_ops,
+ .flags = CLK_IS_ROOT,
+ },
+ [MAX77802_CLK_32K_CP] = {
+ .name = "32khz_cp",
+ .ops = &max_gen_clk_ops,
+ .flags = CLK_IS_ROOT,
+ },
+};
+
+static int max77802_clk_probe(struct platform_device *pdev)
+{
+ struct max77802_dev *iodev = dev_get_drvdata(pdev->dev.parent);
+ int ret;
+
+ ret = max_gen_clk_probe(pdev, iodev->regmap, MAX77802_REG_32KHZ,
+ max77802_clks_init, MAX77802_CLKS_NUM);
+
+ if (ret) {
+ dev_err(&pdev->dev, "generic probe failed %d\n", ret);
+ return ret;
+ }
+
+ /* Enable low-jitter mode on the 32khz clocks. */
+ ret = regmap_update_bits(iodev->regmap, MAX77802_REG_32KHZ,
+ 1 << MAX77802_CLOCK_LOW_JITTER_SHIFT,
+ 1 << MAX77802_CLOCK_LOW_JITTER_SHIFT);
+ if (ret < 0)
+ dev_err(&pdev->dev, "failed to enable low-jitter mode\n");
+
+ return ret;
+}
+
+static int max77802_clk_remove(struct platform_device *pdev)
+{
+ return max_gen_clk_remove(pdev, MAX77802_CLKS_NUM);
+}
+
+static const struct platform_device_id max77802_clk_id[] = {
+ { "max77802-clk", 0},
+ { },
+};
+MODULE_DEVICE_TABLE(platform, max77802_clk_id);
+
+static struct platform_driver max77802_clk_driver = {
+ .driver = {
+ .name = "max77802-clk",
+ .owner = THIS_MODULE,
+ },
+ .probe = max77802_clk_probe,
+ .remove = max77802_clk_remove,
+ .id_table = max77802_clk_id,
+};
+
+module_platform_driver(max77802_clk_driver);
+
+MODULE_DESCRIPTION("MAXIM 77802 Clock Driver");
+MODULE_AUTHOR("Javier Martinez Canillas <javier.martinez@collabora.co.uk>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/mfd/max77802.c b/drivers/mfd/max77802.c
index c9dcbab..ae73bb4 100644
--- a/drivers/mfd/max77802.c
+++ b/drivers/mfd/max77802.c
@@ -38,6 +38,7 @@

static const struct mfd_cell max77802_devs[] = {
{ .name = "max77802-pmic", },
+ { .name = "max77802-clk", },
};

static bool max77802_pmic_is_accessible_reg(struct device *dev,
diff --git a/include/dt-bindings/clock/maxim,max77802.h b/include/dt-bindings/clock/maxim,max77802.h
new file mode 100644
index 0000000..997312e
--- /dev/null
+++ b/include/dt-bindings/clock/maxim,max77802.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2014 Google, Inc
+ *
+ * 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.
+ *
+ * Device Tree binding constants clocks for the Maxim 77802 PMIC.
+ */
+
+#ifndef _DT_BINDINGS_CLOCK_MAXIM_MAX77802_CLOCK_H
+#define _DT_BINDINGS_CLOCK_MAXIM_MAX77802_CLOCK_H
+
+/* Fixed rate clocks. */
+
+#define MAX77802_CLK_32K_AP 0
+#define MAX77802_CLK_32K_CP 1
+
+/* Total number of clocks. */
+#define MAX77802_CLKS_NUM (MAX77802_CLK_32K_CP + 1)
+
+#endif /* _DT_BINDINGS_CLOCK_MAXIM_MAX77802_CLOCK_H */
--
2.0.0.rc2