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Gmane
From: Laxman Dewangan <ldewangan <at> nvidia.com>
Subject: [PATCH V4] clk: palmas: add clock driver for palmas
Newsgroups: gmane.linux.kernel
Date: Wednesday 9th October 2013 11:04:47 UTC (over 3 years ago)
Palmas devices has two clock output CLK32K_KG and CLK32K_KG_AUDIO
which can be enable/disable through software.

Add clock driver support for the Palmas 32KHz clocks.

Signed-off-by: Laxman Dewangan 
---
Changes from V1: 
- Call prepare if the clk is needed for boot-enable or sleep control.
- change is_enabled to is_prepared.
- Added ops palmas_clks_recalc_rate.
- Added of_clk_add_provider().

Changes from V2:
- Convert magic number to defines.

Changes from V3:
- Drop the option of clock enable at boot.
- Add the dt-binding header for DTS file and added macros for ext pin and
  clock id.
- Rephrase some of sentences.
- Error check on init conifgurations.
- Code cleanups for getting  rid of some of enums.

 .../devicetree/bindings/clock/clk-palmas.txt       |   50 +++
 drivers/clk/Kconfig                                |    7 +
 drivers/clk/Makefile                               |    1 +
 drivers/clk/clk-palmas.c                           |  333
++++++++++++++++++++
 include/dt-bindings/mfd/palmas.h                   |   22 ++
 5 files changed, 413 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/clock/clk-palmas.txt
 create mode 100644 drivers/clk/clk-palmas.c
 create mode 100644 include/dt-bindings/mfd/palmas.h

diff --git a/Documentation/devicetree/bindings/clock/clk-palmas.txt
b/Documentation/devicetree/bindings/clock/clk-palmas.txt
new file mode 100644
index 0000000..907c454
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/clk-palmas.txt
@@ -0,0 +1,50 @@
+* Palmas 32KHz clocks *
+
+Palmas device has two clock output pins for 32KHz, KG and KG_AUDIO.
+
+This binding uses the common clock binding ./clock-bindings.txt.
+
+Required properties:
+- compatible : shall be "ti,palmas-clk".
+- #clock-cells : from common clock binding; shall be set to 1. The clock
id for
+		different clocks are:
+			0 for CLK32K_KG
+			1 for CLK32K_KG_AUDIO.
+		The macros of clocks id for DTS is defined at
+			dt-bindings/mfd/palmas.h
+
+Optional subnode:
+	The clock node has optional subnode to provide the init configuration of
+	clocks like sleep control.
+
+	The subnode name is fixed and it should be
+		clk32k_kg for the 32KHz KG clock.
+		clk32k_kg_audio for the 32KHz KG_AUDIO clock.
+
+	Optional subnode properties:
+	ti,external-sleep-control: The external enable input pins controlled the
+		enable/disable of clocks.  The external enable input pins ENABLE1,
+		ENABLE2 and NSLEEP. The valid values for the external pins are:
+			1 for ENABLE1
+			2 for ENABLE2
+			3 for NSLEEP.
+		Option 0 or missing this property means the clock is
+		enabled/disabled via register access and these pins do
+		not have any control.
+		The macros of external control pins for DTS is defined at
+			dt-bindings/mfd/palmas.h
+
+Example:
+	#include 
+	...
+	palmas: [email protected] {
+		...
+		clock {
+			compatible = "ti,palmas-clk";
+			#clock-cells = <1>;
+			clk32k_kg {
+				ti,external-sleep-control = ;
+			};
+		};
+		...
+	};
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 279407a..6b8c233 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -93,6 +93,13 @@ config CLK_PPC_CORENET
 	  This adds the clock driver support for Freescale PowerPC corenet
 	  platforms using common clock framework.
 
+config COMMON_CLK_PALMAS
+	tristate "Clock driver for TI Palmas devices"
+	depends on MFD_PALMAS
+	---help---
+	  This driver supports TI Palmas devices 32KHz output KG and KG_AUDIO
+	  using common clock framework.
+
 endmenu
 
 source "drivers/clk/mvebu/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 7b11106..32e04cf 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -43,3 +43,4 @@ obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o
 obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o
 obj-$(CONFIG_CLK_TWL6040)	+= clk-twl6040.o
 obj-$(CONFIG_CLK_PPC_CORENET)	+= clk-ppc-corenet.o
+obj-$(CONFIG_COMMON_CLK_PALMAS)	+= clk-palmas.o
diff --git a/drivers/clk/clk-palmas.c b/drivers/clk/clk-palmas.c
new file mode 100644
index 0000000..e6e56d1
--- /dev/null
+++ b/drivers/clk/clk-palmas.c
@@ -0,0 +1,333 @@
+/*
+ * Clock driver for Palmas device.
+ *
+ * Copyright (c) 2013, NVIDIA Corporation.
+ *
+ * Author: Laxman Dewangan 
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA
+ */
+
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#define PALMAS_CLOCK_MAX			2
+
+#define PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE1	1
+#define PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE2	2
+#define PALMAS_CLOCK_DT_EXT_CONTROL_NSLEEP	3
+
+struct palmas_clks;
+
+struct palmas_clk32k_desc {
+	const char *clk_name;
+	unsigned int control_reg;
+	unsigned int enable_mask;
+	unsigned int sleep_mask;
+	unsigned int sleep_reqstr_id;
+};
+
+struct palmas_clock_info {
+	struct clk *clk;
+	struct clk_hw hw;
+	struct palmas_clk32k_desc *clk_desc;
+	struct palmas_clks *palmas_clk;
+	int ext_control_pin;
+};
+
+struct palmas_clks {
+	struct device *dev;
+	struct palmas *palmas;
+	struct clk_onecell_data clk_data;
+	struct palmas_clock_info clk_info[PALMAS_CLOCK_MAX];
+};
+
+static struct palmas_clk32k_desc palmas_clk32k_descs[] = {
+	{
+		.clk_name = "clk32k_kg",
+		.control_reg = PALMAS_CLK32KG_CTRL,
+		.enable_mask = PALMAS_CLK32KG_CTRL_MODE_ACTIVE,
+		.sleep_mask = PALMAS_CLK32KG_CTRL_MODE_SLEEP,
+		.sleep_reqstr_id = PALMAS_EXTERNAL_REQSTR_ID_CLK32KG,
+	}, {
+		.clk_name = "clk32k_kg_audio",
+		.control_reg = PALMAS_CLK32KGAUDIO_CTRL,
+		.enable_mask = PALMAS_CLK32KG_CTRL_MODE_ACTIVE,
+		.sleep_mask = PALMAS_CLK32KG_CTRL_MODE_SLEEP,
+		.sleep_reqstr_id = PALMAS_EXTERNAL_REQSTR_ID_CLK32KGAUDIO,
+	},
+};
+
+static inline struct palmas_clock_info *to_palmas_clks_info(struct clk_hw
*hw)
+{
+	return container_of(hw, struct palmas_clock_info, hw);
+}
+
+static unsigned long palmas_clks_recalc_rate(struct clk_hw *hw,
+	unsigned long parent_rate)
+{
+	return 32768;
+}
+
+static int palmas_clks_prepare(struct clk_hw *hw)
+{
+	struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
+	struct palmas_clks *palmas_clks = cinfo->palmas_clk;
+	int ret;
+
+	ret = palmas_update_bits(palmas_clks->palmas, PALMAS_RESOURCE_BASE,
+			cinfo->clk_desc->control_reg,
+			cinfo->clk_desc->enable_mask,
+			cinfo->clk_desc->enable_mask);
+	if (ret < 0)
+		dev_err(palmas_clks->dev, "Reg 0x%02x update failed, %d\n",
+			cinfo->clk_desc->control_reg, ret);
+
+	return ret;
+}
+
+static void palmas_clks_unprepare(struct clk_hw *hw)
+{
+	struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
+	struct palmas_clks *palmas_clks = cinfo->palmas_clk;
+	int ret;
+
+	/*
+	 * Clock can be disabled through external pin if it is externally
+	 * controlled.
+	 */
+	if (cinfo->ext_control_pin)
+		return;
+
+	ret = palmas_update_bits(palmas_clks->palmas, PALMAS_RESOURCE_BASE,
+			cinfo->clk_desc->control_reg,
+			cinfo->clk_desc->enable_mask, 0);
+	if (ret < 0)
+		dev_err(palmas_clks->dev, "Reg 0x%02x update failed, %d\n",
+			cinfo->clk_desc->control_reg, ret);
+
+}
+
+static int palmas_clks_is_prepared(struct clk_hw *hw)
+{
+	struct palmas_clock_info *cinfo = to_palmas_clks_info(hw);
+	struct palmas_clks *palmas_clks = cinfo->palmas_clk;
+	int ret;
+	u32 val;
+
+	if (cinfo->ext_control_pin)
+		return 1;
+
+	ret = palmas_read(palmas_clks->palmas, PALMAS_RESOURCE_BASE,
+			cinfo->clk_desc->control_reg, &val);
+	if (ret < 0) {
+		dev_err(palmas_clks->dev, "Reg 0x%02x read failed, %d\n",
+				cinfo->clk_desc->control_reg, ret);
+		return ret;
+	}
+	return !!(val & cinfo->clk_desc->enable_mask);
+}
+
+static struct clk_ops palmas_clks_ops = {
+	.prepare	= palmas_clks_prepare,
+	.unprepare	= palmas_clks_unprepare,
+	.is_prepared	= palmas_clks_is_prepared,
+	.recalc_rate	= palmas_clks_recalc_rate,
+};
+
+static struct clk_init_data palmas_clks_hw_init[PALMAS_CLOCK_MAX] = {
+	{
+		.name = "clk32k_kg",
+		.ops = &palmas_clks_ops,
+		.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED,
+	}, {
+		.name = "clk32k_kg_audio",
+		.ops = &palmas_clks_ops,
+		.flags = CLK_IS_ROOT | CLK_IGNORE_UNUSED,
+	},
+};
+
+static int palmas_clks_get_clk_data(struct platform_device *pdev,
+	struct palmas_clks *palmas_clks)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct device_node *child;
+	struct palmas_clock_info *cinfo;
+	unsigned int prop;
+	int ret;
+	int i;
+
+	for (i = 0; i < PALMAS_CLOCK_MAX; ++i) {
+		child = of_get_child_by_name(node,
+				palmas_clk32k_descs[i].clk_name);
+		if (!child)
+			continue;
+
+		cinfo = &palmas_clks->clk_info[i];
+
+		ret = of_property_read_u32(child, "ti,external-sleep-control",
+					&prop);
+		if (!ret) {
+			switch (prop) {
+			case PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE1:
+				prop = PALMAS_EXT_CONTROL_ENABLE1;
+				break;
+			case PALMAS_CLOCK_DT_EXT_CONTROL_ENABLE2:
+				prop = PALMAS_EXT_CONTROL_ENABLE2;
+				break;
+			case PALMAS_CLOCK_DT_EXT_CONTROL_NSLEEP:
+				prop = PALMAS_EXT_CONTROL_NSLEEP;
+				break;
+			default:
+				WARN_ON(1);
+				dev_warn(&pdev->dev,
+					"%s: Invalid ext control option: %u\n",
+					child->name, prop);
+				prop = 0;
+				break;
+			}
+			cinfo->ext_control_pin = prop;
+		}
+	}
+
+	return 0;
+}
+
+static int palmas_clks_init_configure(struct palmas_clock_info *cinfo)
+{
+	struct palmas_clks *palmas_clks = cinfo->palmas_clk;
+	int ret;
+
+	ret = palmas_update_bits(palmas_clks->palmas, PALMAS_RESOURCE_BASE,
+			cinfo->clk_desc->control_reg,
+			cinfo->clk_desc->sleep_mask, 0);
+	if (ret < 0) {
+		dev_err(palmas_clks->dev, "Reg 0x%02x update failed, %d\n",
+			cinfo->clk_desc->control_reg, ret);
+		return ret;
+	}
+
+	if (cinfo->ext_control_pin) {
+		ret = clk_prepare(cinfo->clk);
+		if (ret < 0) {
+			dev_err(palmas_clks->dev,
+				"Clock prep failed, %d\n", ret);
+			return ret;
+		}
+
+		ret = palmas_ext_control_req_config(palmas_clks->palmas,
+				cinfo->clk_desc->sleep_reqstr_id,
+				cinfo->ext_control_pin, true);
+		if (ret < 0) {
+			dev_err(palmas_clks->dev,
+				"Ext config for %s failed, %d\n",
+				cinfo->clk_desc->clk_name, ret);
+			return ret;
+		}
+	}
+
+	return ret;
+}
+
+static int palmas_clks_probe(struct platform_device *pdev)
+{
+	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
+	struct palmas_clock_info *cinfo;
+	struct palmas_clks *palmas_clks;
+	struct clk *clk;
+	int i, ret;
+
+	palmas_clks = devm_kzalloc(&pdev->dev, sizeof(*palmas_clks),
+				GFP_KERNEL);
+	if (!palmas_clks)
+		return -ENOMEM;
+
+	palmas_clks->clk_data.clks = devm_kzalloc(&pdev->dev,
+			PALMAS_CLOCK_MAX * sizeof(*palmas_clks->clk_data.clks),
+			GFP_KERNEL);
+	if (!palmas_clks->clk_data.clks)
+		return -ENOMEM;
+
+	palmas_clks_get_clk_data(pdev, palmas_clks);
+	platform_set_drvdata(pdev, palmas_clks);
+
+	palmas_clks->dev = &pdev->dev;
+	palmas_clks->palmas = palmas;
+
+	for (i = 0; i < PALMAS_CLOCK_MAX; i++) {
+		cinfo = &palmas_clks->clk_info[i];
+		cinfo->clk_desc = &palmas_clk32k_descs[i];
+		cinfo->hw.init = &palmas_clks_hw_init[i];
+		cinfo->palmas_clk = palmas_clks;
+		clk = devm_clk_register(&pdev->dev, &cinfo->hw);
+		if (IS_ERR(clk)) {
+			ret = PTR_ERR(clk);
+			dev_err(&pdev->dev, "Fail to register clock %s, %d\n",
+				palmas_clk32k_descs[i].clk_name, ret);
+			return ret;
+		}
+
+		cinfo->clk = clk;
+		palmas_clks->clk_data.clks[i] = clk;
+		palmas_clks->clk_data.clk_num++;
+		ret = palmas_clks_init_configure(cinfo);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "Clock config failed, %d\n", ret);
+			return ret;
+		}
+	}
+
+	ret = of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get,
+			&palmas_clks->clk_data);
+	if (ret < 0)
+		dev_err(&pdev->dev, "Fail to add clock driver, %d\n", ret);
+	return ret;
+}
+
+static int palmas_clks_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+	return 0;
+}
+
+static struct of_device_id of_palmas_clks_match_tbl[] = {
+	{ .compatible = "ti,palmas-clk", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, of_palmas_clks_match_tbl);
+
+static struct platform_driver palmas_clks_driver = {
+	.driver = {
+		.name = "palmas-clk",
+		.owner = THIS_MODULE,
+		.of_match_table = of_palmas_clks_match_tbl,
+	},
+	.probe = palmas_clks_probe,
+	.remove = palmas_clks_remove,
+};
+
+module_platform_driver(palmas_clks_driver);
+
+MODULE_DESCRIPTION("Clock driver for Palmas Series Devices");
+MODULE_ALIAS("platform:palmas-clk");
+MODULE_AUTHOR("Laxman Dewangan ");
+MODULE_LICENSE("GPL v2");
diff --git a/include/dt-bindings/mfd/palmas.h
b/include/dt-bindings/mfd/palmas.h
new file mode 100644
index 0000000..dcfa5fc
--- /dev/null
+++ b/include/dt-bindings/mfd/palmas.h
@@ -0,0 +1,22 @@
+/*
+ * This header provides macros for Palmas device bindings.
+ *
+ * Copyright (c) 2013, NVIDIA Corporation.
+ *
+ * Author: Laxman Dewangan 
+ *
+ */
+
+#ifndef __DT_BINDINGS_PALMAS_H__
+#define __DT_BINDINGS_PALMAS_H
+
+/* External control pins */
+#define PALMAS_EXT_CONTROL_PIN_ENABLE1	1
+#define PALMAS_EXT_CONTROL_PIN_ENABLE2	2
+#define PALMAS_EXT_CONTROL_PIN_NSLEEP	3
+
+/* Palmas device's clocks id */
+#define PALMAS_CLOCKS_CLK32K_KG		0
+#define PALMAS_CLOCKS_CLK32K_KG_AUDIO	1
+
+#endif /* __DT_BINDINGS_PALMAS_H */
-- 
1.7.1.1

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