[PATCH v5 0/4] Initial support for ImgTec PWM DAC and PDM DAC

[PATCH v5 0/4] Initial support for ImgTec PWM DAC and PDM DAC

[Naidu Tellapati]

The Pistachio SOC from Imagination Technologies includes – 4x PDM blocks
and 1x “basic PWM” block with four output channels. These share 4 MFIO pins,
each PWM channel being muxed with each PDM block output (0-3 muxed with 0-3)
using the CR_PERIP_PWM_PDM_CONTROL register in the peripheral wrapper
register bank (offset 0x140). The PDM and PWM outputs are used to control
targets such as LCD backlight.

The PWM driver uses Linux PWM framework. Since the PDM does not fit into PWM
framework we have implemented it as a MISC driver.

The series is based on v3.18-rc5.

Changes from v4:

 * Removed CR_prefix from the defined macros.

 * Folded same data type varibles in one line.
 
 * Removed cr-periph property from PWM DT binding document.

 * Removed regmap_update_bits from img_pwm_enable and img_pwm_disable functions.

 * Addressed few more comments given in v4.

Changes from v3:

 * Addressed couple of comments given in v3.

Changes from v2:

 * Added depends on MIPS || COMPILE_TEST.

 * Corrected the logic while calculating time base steps.

 * Addressed few other minor comments given in v2.

Changes from v1:

 * Used regmap_update_bits at some places in the driver.

 * Placed some #defines next to their register.

 * Added depends on HAS_IOMEM in Kconfig.

 * Removed unnecessary paragraph from file header.

 * Defined register masks in a readable way.

 * Renamed clk-names with clock-names.

 * Added system interface clock in DT binding document.

 * Addressed few other minor review comments given in v1.

Naidu Tellapati (4):
  pwm: Imagination Technologies PWM DAC driver
  DT: pwm: Add binding document for IMG PWM DAC
  pdm: Imagination Technologies PDM DAC driver
  DT: pdm: Add binding document for IMG PDM DAC

 Documentation/devicetree/bindings/misc/img-pdm.txt |   54 ++
 Documentation/devicetree/bindings/pwm/img-pwm.txt  |   21 +
 drivers/misc/Kconfig                               |   16 +
 drivers/misc/Makefile                              |    1 +
 drivers/misc/img-pdm.c                             |  653 ++++++++++++++++++++
 drivers/pwm/Kconfig                                |   12 +
 drivers/pwm/Makefile                               |    1 +
 drivers/pwm/pwm-img.c                              |  240 +++++++
 include/linux/img_pdm.h                            |   52 ++
 9 files changed, 1050 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/misc/img-pdm.txt
 create mode 100644 Documentation/devicetree/bindings/pwm/img-pwm.txt
 create mode 100644 drivers/misc/img-pdm.c
 create mode 100644 drivers/pwm/pwm-img.c
 create mode 100644 include/linux/img_pdm.h

[PATCH v5 1/4] pwm: Imagination Technologies PWM DAC driver

[Naidu Tellapati]

The Pistachio SOC from Imagination Technologies includes a Pulse Width
Modulation DAC which produces 1 to 4 digital bit-outputs which represent
digital waveforms. These PWM outputs are primarily in charge of controlling
backlight LED devices

Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Sai Masarapu <Sai.Masarapu@imgtec.com>
---
 drivers/pwm/Kconfig   |   12 +++
 drivers/pwm/Makefile  |    1 +
 drivers/pwm/pwm-img.c |  240 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 253 insertions(+), 0 deletions(-)
 create mode 100644 drivers/pwm/pwm-img.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index ef2dd2e..db4ccfd 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -110,6 +110,18 @@ config PWM_FSL_FTM
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-fsl-ftm.
 
+config PWM_IMG
+	tristate "Imagination Technologies PWM driver"
+	depends on HAS_IOMEM
+	depends on COMMON_CLK
+	depends on MIPS || COMPILE_TEST
+	help
+	  Generic PWM framework driver for Imagination Technologies
+	  PWM block which supports 4 channels.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-img.
+
 config PWM_IMX
 	tristate "i.MX PWM support"
 	depends on ARCH_MXC
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index c458606..29655fd 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
 obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
 obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
+obj-$(CONFIG_PWM_IMG)		+= pwm-img.o
 obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
 obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o
 obj-$(CONFIG_PWM_LP3943)	+= pwm-lp3943.o
diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
new file mode 100644
index 0000000..a837372
--- /dev/null
+++ b/drivers/pwm/pwm-img.c
@@ -0,0 +1,240 @@
+/*
+ * Imagination Technologies Pulse Width Modulator driver
+ *
+ * Copyright (c) 2014, Imagination Technologies
+ *
+ * Based on drivers/pwm/pwm-tegra.c, Copyright (c) 2010, NVIDIA Corporation
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+/* PWM registers */
+#define PWM_CTRL_CFG				0x0000
+#define PWM_CTRL_CFG_NO_SUB_DIV			0
+#define PWM_CTRL_CFG_SUB_DIV0			1
+#define PWM_CTRL_CFG_SUB_DIV1			2
+#define PWM_CTRL_CFG_SUB_DIV0_DIV1		3
+#define PWM_CTRL_CFG_DIV_SHIFT(ch)		((ch) * 2 + 4)
+#define PWM_CTRL_CFG_DIV_MASK			0x3
+
+#define PWM_CH_CFG(ch)				(0x4 + (ch) * 4)
+#define PWM_CH_CFG_TMBASE_SHIFT			0
+#define PWM_CH_CFG_DUTY_SHIFT			16
+
+#define PERIP_PWM_PDM_CONTROL			0x0140
+#define PERIP_PWM_PDM_CONTROL_CH_MASK		0x1
+#define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch)	((ch) * 4)
+
+#define MAX_TMBASE_STEPS			65536
+
+struct img_pwm_chip {
+	struct device	*dev;
+	struct pwm_chip	chip;
+	struct clk	*pwm_clk;
+	struct clk	*sys_clk;
+	void __iomem	*base;
+};
+
+static inline struct img_pwm_chip *to_img_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct img_pwm_chip, chip);
+}
+
+static inline void img_pwm_writel(struct img_pwm_chip *chip,
+				  u32 reg, u32 val)
+{
+	writel(val, chip->base + reg);
+}
+
+static inline u32 img_pwm_readl(struct img_pwm_chip *chip,
+					 u32 reg)
+{
+	return readl(chip->base + reg);
+}
+
+static int img_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			  int duty_ns, int period_ns)
+{
+	u32 val, div, duty, timebase;
+	unsigned long mul, output_clk_hz, input_clk_hz;
+	struct img_pwm_chip *pwm_chip;
+
+	pwm_chip = to_img_pwm_chip(chip);
+
+	input_clk_hz = clk_get_rate(pwm_chip->pwm_clk);
+	output_clk_hz = DIV_ROUND_UP(NSEC_PER_SEC, period_ns);
+
+	mul = DIV_ROUND_UP(input_clk_hz, output_clk_hz);
+	if (mul <= MAX_TMBASE_STEPS) {
+		div = PWM_CTRL_CFG_NO_SUB_DIV;
+		timebase = DIV_ROUND_UP(mul, 1);
+	} else if (mul <= MAX_TMBASE_STEPS * 8) {
+		div = PWM_CTRL_CFG_SUB_DIV0;
+		timebase = DIV_ROUND_UP(mul, 8);
+	} else if (mul <= MAX_TMBASE_STEPS * 64) {
+		div = PWM_CTRL_CFG_SUB_DIV1;
+		timebase = DIV_ROUND_UP(mul, 64);
+	} else if (mul <= MAX_TMBASE_STEPS * 512) {
+		div = PWM_CTRL_CFG_SUB_DIV0_DIV1;
+		timebase = DIV_ROUND_UP(mul, 512);
+	} else if (mul > MAX_TMBASE_STEPS * 512) {
+		dev_err(chip->dev,
+			"failed to configure timebase steps/divider value.\n");
+		return -EINVAL;
+	}
+
+	duty = DIV_ROUND_UP(timebase * duty_ns, period_ns);
+
+	val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+	val &= ~(PWM_CTRL_CFG_DIV_MASK << PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm));
+	val |= (div & PWM_CTRL_CFG_DIV_MASK) <<
+	       PWM_CTRL_CFG_DIV_SHIFT(pwm->hwpwm);
+	img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+
+	val = (duty << PWM_CH_CFG_DUTY_SHIFT) |
+	      (timebase << PWM_CH_CFG_TMBASE_SHIFT);
+	img_pwm_writel(pwm_chip, PWM_CH_CFG(pwm->hwpwm), val);
+
+	return 0;
+}
+
+static int img_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 val;
+	struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
+
+	val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+	val |= BIT(pwm->hwpwm);
+	img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+
+	return 0;
+}
+
+static void img_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	u32 val;
+	struct img_pwm_chip *pwm_chip = to_img_pwm_chip(chip);
+
+	val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+	val &= ~BIT(pwm->hwpwm);
+	img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+}
+
+static const struct pwm_ops img_pwm_ops = {
+	.config = img_pwm_config,
+	.enable = img_pwm_enable,
+	.disable = img_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int img_pwm_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *res;
+	struct img_pwm_chip *pwm;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	pwm->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pwm->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pwm->base))
+		return PTR_ERR(pwm->base);
+
+	pwm->sys_clk = devm_clk_get(&pdev->dev, "sys");
+	if (IS_ERR(pwm->sys_clk)) {
+		dev_err(&pdev->dev, "failed to get system clock.\n");
+		return PTR_ERR(pwm->sys_clk);
+	}
+
+	pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
+	if (IS_ERR(pwm->pwm_clk)) {
+		dev_err(&pdev->dev, "failed to get pwm clock.\n");
+		return PTR_ERR(pwm->pwm_clk);
+	}
+
+	ret = clk_prepare_enable(pwm->sys_clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not prepare or enable sys clock.\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(pwm->pwm_clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not prepare or enable pwm clock.\n");
+		goto disable_sysclk;
+	}
+
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.ops = &img_pwm_ops;
+	pwm->chip.base = -1;
+	pwm->chip.npwm = 4;
+
+	ret = pwmchip_add(&pwm->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add failed: %d\n", ret);
+		goto disable_pwmclk;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+
+disable_pwmclk:
+	clk_disable_unprepare(pwm->pwm_clk);
+disable_sysclk:
+	clk_disable_unprepare(pwm->sys_clk);
+
+	return 0;
+}
+
+static int img_pwm_remove(struct platform_device *pdev)
+{
+	struct img_pwm_chip *pwm_chip = platform_get_drvdata(pdev);
+	u32 val;
+	unsigned int i;
+
+	for (i = 0; i < pwm_chip->chip.npwm; i++) {
+		val = img_pwm_readl(pwm_chip, PWM_CTRL_CFG);
+		val &= ~BIT(i);
+		img_pwm_writel(pwm_chip, PWM_CTRL_CFG, val);
+	}
+
+	clk_disable_unprepare(pwm_chip->pwm_clk);
+	clk_disable_unprepare(pwm_chip->sys_clk);
+
+	return pwmchip_remove(&pwm_chip->chip);
+}
+
+static const struct of_device_id img_pwm_of_match[] = {
+	{ .compatible = "img,pistachio-pwm", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, img_pwm_of_match);
+
+static struct platform_driver img_pwm_driver = {
+	.driver = {
+		.name = "img-pwm",
+		.of_match_table = of_match_ptr(img_pwm_of_match),
+	},
+	.probe = img_pwm_probe,
+	.remove = img_pwm_remove,
+};
+module_platform_driver(img_pwm_driver);
+
+MODULE_AUTHOR("Sai Masarapu <Sai.Masarapu@imgtec.com>");
+MODULE_DESCRIPTION("Imagination Technologies PWM DAC driver");
+MODULE_LICENSE("GPL v2");
-- 
1.7.0.4

[PATCH v5 2/4] DT: pwm: Add binding document for IMG PWM DAC

[Naidu Tellapati]

Add binding document for IMG Pulse Width Modulator (PWM) DAC present on the
Pistachio SOC. The PWM DAC has four channels.

Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Sai Masarapu <Sai.Masarapu@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
---
No changes from v4.
---
 Documentation/devicetree/bindings/pwm/img-pwm.txt |   21 +++++++++++++++++++++
 1 files changed, 21 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/pwm/img-pwm.txt

diff --git a/Documentation/devicetree/bindings/pwm/img-pwm.txt b/Documentation/devicetree/bindings/pwm/img-pwm.txt
new file mode 100644
index 0000000..046893c
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/img-pwm.txt
@@ -0,0 +1,21 @@
+*Imagination Technologies PWM DAC driver
+
+Required properties:
+  - compatible: Should be "img,pistachio-pwm"
+  - reg: Should contain physical base address and length of pwm registers.
+  - clocks: Must contain an entry for each entry in clock-names.
+	See ../clock/clock-bindings.txt for details.
+  - clock-names: Must include the following entries:
+    - pwm: PWM operating clock.
+    - sys: PWM system interface clock.
+  - #pwm-cells: Should be 2. See pwm.txt in this directory for the
+	description of the cells format.
+
+Example:
+	pwm: pwm@18101300 {
+		compatible = "img,pistachio-pwm";
+		reg = <0x18101300 0x100>;
+		clocks = <&pwm_clk>, <&system_clk>;
+		clock-names = "pwm", "sys";
+		#pwm-cells = <2>;
+	};
-- 
1.7.0.4

[PATCH v5 3/4] pdm: Imagination Technologies PDM DAC driver

[Naidu Tellapati]

The Pistachio SOC from Imagination Technologies includes a Pulse Density
Modulation DAC which produces a form of analogue output according to the
relative density of output pulses to the intended analogue signal amplitude.
Four PDM outputs are provided that can be used to control targets such as LCD
backlight.

Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Arul Ramasamy <Arul.Ramasamy@imgtec.com>
---
 drivers/misc/Kconfig    |   16 ++
 drivers/misc/Makefile   |    1 +
 drivers/misc/img-pdm.c  |  653 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/img_pdm.h |   52 ++++
 4 files changed, 722 insertions(+), 0 deletions(-)
 create mode 100644 drivers/misc/img-pdm.c
 create mode 100644 include/linux/img_pdm.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index bbeb451..9f0148a 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -515,6 +515,22 @@ config VEXPRESS_SYSCFG
 	  bus. System Configuration interface is one of the possible means
 	  of generating transactions on this bus.
 
+config IMG_PDM
+	tristate "Imagination Technologies PDM driver"
+	depends on HAS_IOMEM
+	depends on MFD_SYSCON
+	depends on COMMON_CLK
+	depends on MIPS || COMPILE_TEST
+
+	help
+	  PDM driver for Imagination Technologies PDM block which supports 4
+	  blocks.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called img-pdm.
+
+
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7d5c4cd..d8c7d55 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -56,3 +56,4 @@ obj-$(CONFIG_GENWQE)		+= genwqe/
 obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_VEXPRESS_SYSCFG)	+= vexpress-syscfg.o
 obj-$(CONFIG_CXL_BASE)		+= cxl/
+obj-$(CONFIG_IMG_PDM)		+= img-pdm.o
diff --git a/drivers/misc/img-pdm.c b/drivers/misc/img-pdm.c
new file mode 100644
index 0000000..ff94b88
--- /dev/null
+++ b/drivers/misc/img-pdm.c
@@ -0,0 +1,653 @@
+/**
+ * Imagination Technologies Pulse Density Modulator driver
+ *
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ *
+ * 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/capability.h>
+#include <linux/clk.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/img_pdm.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kobject.h>
+#include <linux/list.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+
+struct img_pdm_block *pdm_blocks;
+
+static DEFINE_MUTEX(pdm_lock);
+
+static struct img_pdm_block *of_img_pdm_block_get(struct device_node *np)
+{
+	int err, index;
+	struct of_phandle_args args;
+	struct img_pdm_block *block;
+
+	err = of_parse_phandle_with_args(np, "pdms", "#pdm-cells",
+					 index, &args);
+	if (err) {
+		pr_debug("%s(): can't parse \"pdms\" property\n", __func__);
+		return ERR_PTR(err);
+	}
+
+	if (args.args_count != 2) {
+		pr_debug("%s(): wrong #pwm-cells\n", __func__);
+		return ERR_PTR(-EINVAL);
+	}
+
+	block = img_pdm_block_request(args.args[0]);
+	if (block)
+		img_pdm_block_pulse_in_set(block, args.args[1]);
+
+	return block;
+}
+
+static void of_img_pdm_block_put(struct device_node *np)
+{
+	struct img_pdm_block *block = NULL;
+	struct of_phandle_args args;
+	int err, index;
+
+	err = of_parse_phandle_with_args(np, "pdms", "#pdm-cells",
+					 index, &args);
+	if (err) {
+		pr_debug("%s(): can't parse \"pdms\" property\n", __func__);
+		return;
+	}
+
+	if (args.args_count != 2) {
+		pr_debug("%s(): wrong #pwm-cells\n", __func__);
+		return;
+	}
+
+	if (args.args[0] < 0 || args.args[0] >= NUM_PDM_BLOCKS || !pdm_blocks)
+		return;
+
+	block = &pdm_blocks[args.args[0]];
+	img_pdm_block_free(block);
+}
+
+struct img_pdm_block *img_pdm_block_get(struct device *dev)
+{
+	/* look up via DT */
+	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
+		return of_img_pdm_block_get(dev->of_node);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_get);
+
+void img_pdm_block_put(struct device *dev)
+{
+	/* look up via DT */
+	if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
+		of_img_pdm_block_put(dev->of_node);
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_put);
+
+struct img_pdm_block *img_pdm_block_request(unsigned int pdm_id)
+{
+	struct img_pdm_device *pdm_dev;
+	struct img_pdm_block *block = NULL;
+	unsigned int i;
+
+	mutex_lock(&pdm_lock);
+
+	if (pdm_id < 0 || pdm_id >= IMG_NUM_PDM_BLOCKS || !pdm_blocks)
+		return NULL;
+
+	pdm_dev = pdm_blocks[0].pdm_dev;
+	if (!pdm_dev)
+		return NULL;
+
+	for (i = 0; i < IMG_NUM_PDM_BLOCKS; i++) {
+		if (&pdm_blocks[i] && (pdm_blocks[i].pdm_id == pdm_id)) {
+			block = &pdm_blocks[i];
+			break;
+		}
+	}
+
+	if (!block) {
+		mutex_unlock(&pdm_lock);
+		return NULL;
+	}
+
+	/* Check if block is already requested */
+	if (test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev,
+			"pdm block %d already requested\n", block->pdm_id);
+		mutex_unlock(&pdm_lock);
+		return NULL;
+	}
+
+	set_bit(PDM_CHANNEL_REQUESTED, &block->flags);
+	mutex_unlock(&pdm_lock);
+
+	return block;
+}
+
+int img_pdm_block_free(struct img_pdm_block *block)
+{
+	int i;
+	struct img_pdm_device *pdm_dev;
+
+	mutex_lock(&pdm_lock);
+
+	if (!pdm_blocks || !block) {
+		mutex_unlock(&pdm_lock);
+		return -EINVAL;
+	}
+
+	pdm_dev = pdm_blocks[0].pdm_dev;
+	if (!pdm_dev) {
+		mutex_unlock(&pdm_lock);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < IMG_NUM_PDM_BLOCKS; i++) {
+		if (&pdm_blocks[i] && (&pdm_blocks[i] == block))
+			break;
+	}
+
+	if (i == IMG_NUM_PDM_BLOCKS) {
+		dev_err(&pdm_dev->pdev->dev,
+			"Invalid pdm block address to free\n");
+		mutex_unlock(&pdm_lock);
+		return -EINVAL;
+	}
+
+	if (test_bit(PDM_CHANNEL_ENABLED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev,
+			"can't free the block while it is enabled\n");
+		mutex_unlock(&pdm_lock);
+		return -EINVAL;
+	}
+
+	if (!test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev,
+			"trying to free block which is not requested\n");
+		mutex_unlock(&pdm_lock);
+		return -EINVAL;
+	}
+
+	clear_bit(PDM_CHANNEL_REQUESTED, &block->flags);
+
+	mutex_unlock(&pdm_lock);
+
+	return 0;
+}
+
+int img_pdm_block_enable_get(struct img_pdm_block *block)
+{
+	int ret;
+	struct img_pdm_device *pdm_dev;
+
+	if (!block)
+		return -EINVAL;
+
+	pdm_dev = block->pdm_dev;
+
+	if (!test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "pdm block is notrequested\n");
+		return -EINVAL;
+	}
+
+	if (test_bit(PDM_CHANNEL_ENABLED, &block->flags))
+		ret = PERIP_PDM_CHANNEL_ENABLE;
+	else
+		ret = PERIP_PDM_CHANNEL_DISABLE;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_enable_get);
+
+int img_pdm_block_pulse_in_get(struct img_pdm_block *block)
+{
+	int val;
+	struct img_pdm_device *pdm_dev;
+
+	if (!block)
+		return -EINVAL;
+
+	pdm_dev = block->pdm_dev;
+
+	if (!test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "pdm block is notrequested\n");
+		return -EINVAL;
+	}
+
+	regmap_read(pdm_dev->periph_regs,
+		    PERIP_PDM0_VAL +
+		    PERIP_PDM_CH_ADDR_SHIFT(block->pdm_id), &val);
+	val &= PERIP_PDM_SRC_DATA_MASK;
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_pulse_in_get);
+
+int img_pdm_block_enable_set(struct img_pdm_block *block, bool state)
+{
+	struct img_pdm_device *pdm_dev;
+
+	if (!block)
+		return -EINVAL;
+
+	pdm_dev = block->pdm_dev;
+
+	if (!test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "invalid pdm block enable\n");
+		return -EINVAL;
+	}
+
+	if ((state == PERIP_PDM_CHANNEL_ENABLE) &&
+		test_bit(PDM_CHANNEL_ENABLED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "pdm block already enabled\n");
+		return -EBUSY;
+	} else if ((state == PERIP_PDM_CHANNEL_DISABLE) &&
+		!test_bit(PDM_CHANNEL_ENABLED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "pdm block not enabled\n");
+		return -EINVAL;
+	}
+
+	if (state == PERIP_PDM_CHANNEL_ENABLE) {
+		regmap_update_bits(pdm_dev->periph_regs,
+				PERIP_PWM_PDM_CONTROL,
+				PERIP_PWM_PDM_CONTROL_CH_MASK <<
+				PERIP_PWM_PDM_CONTROL_CH_SHIFT(block->pdm_id),
+				1);
+		set_bit(PDM_CHANNEL_ENABLED, &block->flags);
+	} else if (state == PERIP_PDM_CHANNEL_DISABLE) {
+		regmap_update_bits(pdm_dev->periph_regs,
+				PERIP_PWM_PDM_CONTROL,
+				PERIP_PWM_PDM_CONTROL_CH_MASK <<
+				PERIP_PWM_PDM_CONTROL_CH_SHIFT(block->pdm_id),
+				0);
+		regmap_write(pdm_dev->periph_regs,
+			     PERIP_PDM0_VAL +
+			     PERIP_PDM_CH_ADDR_SHIFT(block->pdm_id), 0);
+		clear_bit(PDM_CHANNEL_ENABLED, &block->flags);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_enable_set);
+
+int img_pdm_block_pulse_in_set(struct img_pdm_block *block, u32 val)
+{
+	struct img_pdm_device *pdm_dev;
+
+	if (!block)
+		return -EINVAL;
+
+	pdm_dev = block->pdm_dev;
+
+	if (!test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+		dev_err(&pdm_dev->pdev->dev, "invalid pdm block to configure\n");
+		return -EINVAL;
+	}
+
+	val = val & PERIP_PDM_SRC_DATA_MASK;
+	regmap_write(pdm_dev->periph_regs,
+		     PERIP_PDM0_VAL +
+		     PERIP_PDM_CH_ADDR_SHIFT(block->pdm_id), val);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(img_pdm_block_pulse_in_set);
+
+static ssize_t img_pdm_enable_read(struct kobject *kobj,
+			struct kobj_attribute *attr, char *buf)
+{
+	int ret;
+	unsigned int block_num, val;
+	unsigned char kobj_name[2];
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(kobj_to_dev(kobj->parent));
+	pdm_dev = platform_get_drvdata(pdev);
+	kobj_name[0] = *(kobj->name+3);
+	kobj_name[1] = '\0';
+	ret = kstrtou32(kobj_name, 10, &block_num);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse block number string\n");
+		return ret;
+	}
+
+	val = img_pdm_block_enable_get(&pdm_blocks[block_num]);
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t img_pdm_pulse_in_read(struct kobject *kobj,
+			struct kobj_attribute *attr, char *buf)
+{
+	int ret;
+	unsigned int block_num, val;
+	unsigned char kobj_name[2];
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(kobj_to_dev(kobj->parent));
+	pdm_dev = platform_get_drvdata(pdev);
+	kobj_name[0] = *(kobj->name+3);
+	kobj_name[1] = '\0';
+	ret = kstrtou32(kobj_name, 10, &block_num);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse block number string\n");
+		return ret;
+	}
+
+	val = img_pdm_block_pulse_in_get(&pdm_blocks[block_num]);
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t img_pdm_enable_write(struct kobject *kobj,
+					struct kobj_attribute *attr,
+						const char *buf, size_t size)
+{
+	int ret;
+	unsigned int enable, block_num;
+	unsigned char kobj_name[2];
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(kobj_to_dev(kobj->parent));
+	pdm_dev = platform_get_drvdata(pdev);
+	kobj_name[0] = *(kobj->name+3);
+	kobj_name[1] = '\0';
+	ret = kstrtou32(kobj_name, 10, &block_num);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse block number string\n");
+		return ret;
+	}
+
+	ret = kstrtou32(buf, 10, &enable);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse enable attr value\n");
+		return ret;
+	}
+
+	if (enable > PERIP_PDM_CHANNEL_ENABLE) {
+		dev_err(&pdev->dev, "invalid enable attribute value\n");
+		return ret;
+	}
+
+	ret = img_pdm_block_enable_set(&pdm_blocks[block_num],
+				       enable ? PERIP_PDM_CHANNEL_ENABLE :
+				       PERIP_PDM_CHANNEL_DISABLE);
+	if (ret < 0)
+		return ret;
+
+	return size;
+}
+
+static ssize_t img_pdm_pulse_in_write(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t size)
+{
+	int ret;
+	unsigned int pulse_in, block_num;
+	unsigned char kobj_name[2];
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(kobj_to_dev(kobj->parent));
+	pdm_dev = platform_get_drvdata(pdev);
+	kobj_name[0] = *(kobj->name+3);
+	kobj_name[1] = '\0';
+	ret = kstrtou32(kobj_name, 10, &block_num);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse block number string\n");
+		return ret;
+	}
+
+	ret = kstrtouint(buf, 16, &pulse_in);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"could not parse pulse_in attr value\n");
+		return ret;
+	}
+
+	if (pulse_in > PERIP_PDM_SRC_DATA_MASK) {
+		dev_err(&pdev->dev,
+			"invalid attr value for pulse_in string\n");
+		return -EINVAL;
+	}
+
+	ret = img_pdm_block_pulse_in_set(&pdm_blocks[block_num], pulse_in);
+	if (ret < 0)
+		return ret;
+
+	return size;
+}
+
+#define PDM_ATTR(_name, _mode, _show, _store) \
+struct kobj_attribute pdm_attr_##_name = { \
+	.attr = {.name = __stringify(_name), .mode = _mode}, \
+	.show = _show, \
+	.store = _store, \
+}
+
+static PDM_ATTR(enable, S_IRUGO | S_IWUSR, img_pdm_enable_read,
+		img_pdm_enable_write);
+static PDM_ATTR(pulse_in, S_IRUGO | S_IWUSR, img_pdm_pulse_in_read,
+		img_pdm_pulse_in_write);
+
+static struct attribute *pdm_sysfs_attrs[] = {
+	&pdm_attr_enable.attr,
+	&pdm_attr_pulse_in.attr,
+	NULL,
+};
+
+static const struct attribute_group pdm_attr_group = {
+	.attrs = pdm_sysfs_attrs,
+};
+
+static ssize_t img_pdm_export(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	int ret;
+	unsigned int block_num;
+	unsigned char buf1[5];
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(dev);
+	pdm_dev = platform_get_drvdata(pdev);
+
+	ret = kstrtou32(buf, 10, &block_num);
+	if (ret) {
+		dev_err(&pdev->dev, "could not parse block number string\n");
+		return ret;
+	}
+
+	if (img_pdm_block_request(block_num) == NULL)
+		return -EINVAL;
+
+	memset(buf1, 0, sizeof(buf1));
+	sprintf(buf1, "pdm%d", block_num);
+	pdm_dev->pdm_kobj[block_num] = kobject_create_and_add(buf1,
+							   &pdev->dev.kobj);
+	if (!pdm_dev->pdm_kobj[block_num])
+		return -ENOMEM;
+
+	ret = sysfs_create_group(pdm_dev->pdm_kobj[block_num], &pdm_attr_group);
+	if (ret) {
+		kobject_put(pdm_dev->pdm_kobj[block_num]);
+		dev_err(&pdev->dev, "unable to register device attributes\n");
+		return ret;
+	}
+
+	return size;
+}
+
+static ssize_t img_pdm_unexport(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
+{
+	int ret;
+	unsigned int block_num;
+	struct img_pdm_block *block;
+	struct platform_device *pdev;
+	struct img_pdm_device *pdm_dev;
+
+	pdev = to_platform_device(dev);
+	pdm_dev = platform_get_drvdata(pdev);
+
+	ret = kstrtou32(buf, 10, &block_num);
+	if (ret < 0)
+		return ret;
+
+	if (block_num < 0 || block_num >= IMG_NUM_PDM_BLOCKS) {
+		dev_err(&pdev->dev, "Invalid block number %d\n", block_num);
+		return -EINVAL;
+	}
+
+	block = &pdm_blocks[block_num];
+	if (img_pdm_block_free(block) < 0)
+		return -EINVAL;
+
+	if (pdm_dev->pdm_kobj[block_num]) {
+		sysfs_remove_group(pdm_dev->pdm_kobj[block_num],
+				   &pdm_attr_group);
+		kobject_put(pdm_dev->pdm_kobj[block_num]);
+	}
+
+	return size;
+}
+
+/* The sysfs attributes. */
+static DEVICE_ATTR(export, S_IRUGO | S_IWUSR, NULL, img_pdm_export);
+static DEVICE_ATTR(unexport, S_IRUGO | S_IWUSR, NULL, img_pdm_unexport);
+
+static struct attribute *img_pdm_sysfs_attrs[] = {
+	&dev_attr_export.attr,
+	&dev_attr_unexport.attr,
+	NULL,
+};
+
+static const struct attribute_group img_pdm_attr_group = {
+	.attrs = img_pdm_sysfs_attrs,
+};
+
+static int img_pdm_probe(struct platform_device *pdev)
+{
+	int i, ret;
+	struct img_pdm_device *pdm_dev;
+
+	pdm_dev = devm_kzalloc(&pdev->dev,
+			       sizeof(struct img_pdm_device), GFP_KERNEL);
+	if (!pdm_dev)
+		return -ENOMEM;
+
+	pdm_dev->pdm_kobj = devm_kzalloc(&pdev->dev,
+					 IMG_NUM_PDM_BLOCKS *
+					 sizeof(struct img_pdm_device *),
+					 GFP_KERNEL);
+	if (!pdm_dev->pdm_kobj)
+		return -ENOMEM;
+
+	pdm_blocks = devm_kzalloc(&pdev->dev,
+				  IMG_NUM_PDM_BLOCKS *
+				  sizeof(struct img_pdm_block), GFP_KERNEL);
+	if (!pdm_blocks)
+		return -ENOMEM;
+
+	pdm_dev->periph_regs = syscon_regmap_lookup_by_phandle(
+					pdev->dev.of_node, "img,cr-periph");
+	if (IS_ERR(pdm_dev->periph_regs))
+		return PTR_ERR(pdm_dev->periph_regs);
+
+	pdm_dev->clk = devm_clk_get(&pdev->dev, "pdm");
+	if (IS_ERR(pdm_dev->clk)) {
+		dev_err(&pdev->dev, "failed to get pdm clock\n");
+		return PTR_ERR(pdm_dev->clk);
+	}
+
+	ret = clk_prepare_enable(pdm_dev->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "could not prepare or enable pdm clock.\n");
+		return ret;
+	}
+
+	for (i = 0; i < IMG_NUM_PDM_BLOCKS; i++) {
+		pdm_blocks[i].pdm_id = i;
+		pdm_blocks[i].pdm_dev = pdm_dev;
+	}
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &img_pdm_attr_group);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register device attributes\n");
+		clk_disable_unprepare(pdm_dev->clk);
+		return ret;
+	}
+
+	pdm_dev->pdev = pdev;
+	platform_set_drvdata(pdev, pdm_dev);
+
+	return 0;
+}
+
+static int img_pdm_remove(struct platform_device *pdev)
+{
+	int i;
+	struct img_pdm_block *block;
+	struct img_pdm_device *pdm_dev;
+
+	pdm_dev = platform_get_drvdata(pdev);
+
+	for (i = 0; i < IMG_NUM_PDM_BLOCKS; i++) {
+		block = &pdm_blocks[i];
+		if (test_bit(PDM_CHANNEL_REQUESTED, &block->flags)) {
+			img_pdm_block_enable_set(block,
+						 PERIP_PDM_CHANNEL_DISABLE);
+			img_pdm_block_pulse_in_set(block, 0);
+			if (pdm_dev->pdm_kobj[i]) {
+				sysfs_remove_group(pdm_dev->pdm_kobj[i],
+						   &pdm_attr_group);
+				kobject_del(pdm_dev->pdm_kobj[i]);
+			}
+		}
+	}
+
+	clk_disable_unprepare(pdm_dev->clk);
+
+	return 0;
+}
+
+static const struct of_device_id img_pdm_of_match[] = {
+	{ .compatible = "img,pistachio-pdm", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, img_pdm_of_match);
+
+static struct platform_driver img_pdm_driver = {
+	.driver = {
+		.name = "imgtec-pdm",
+		.of_match_table = img_pdm_of_match,
+	},
+	.probe = img_pdm_probe,
+	.remove = img_pdm_remove,
+};
+module_platform_driver(img_pdm_driver);
+
+MODULE_AUTHOR("Arul Ramasamy <Arul.Ramasamy@imgtec.com>");
+MODULE_DESCRIPTION("Imagination Technologies PDM driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/img_pdm.h b/include/linux/img_pdm.h
new file mode 100644
index 0000000..79d8d99
--- /dev/null
+++ b/include/linux/img_pdm.h
@@ -0,0 +1,52 @@
+/**
+ * Imagination Technologies Pulse Density Modulator driver
+ *
+ * Copyright (C) 2014 Imagination Technologies Ltd.
+ *
+ * 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.
+ */
+
+#ifndef __IMG_PDM_H
+#define __IMG_PDM_H
+
+/* Registers */
+#define PERIP_PWM_PDM_CONTROL			0x0140
+#define PERIP_PWM_PDM_CONTROL_CH_MASK		0x1
+#define PERIP_PWM_PDM_CONTROL_CH_SHIFT(ch)	((ch) * 4)
+#define PERIP_PDM_CHANNEL_ENABLE		1
+#define PERIP_PDM_CHANNEL_DISABLE		0
+
+#define PERIP_PDM0_VAL				0x0144
+#define PERIP_PDM_CH_ADDR_SHIFT(ch)		((ch) * 4)
+#define PERIP_PDM_SRC_DATA_MASK			0xfff
+
+#define NUM_PDM_BLOCKS				4
+#define PDM_CHANNEL_REQUESTED			1
+#define PDM_CHANNEL_ENABLED			2
+
+struct img_pdm_device {
+	struct clk *clk;
+	struct kobject **pdm_kobj;
+	struct regmap *periph_regs;
+	struct platform_device *pdev;
+};
+
+struct img_pdm_block {
+	unsigned int pdm_id;
+	unsigned long flags;
+	struct img_pdm_device *pdm_dev;
+};
+
+struct img_pdm_block *img_pdm_block_request(unsigned int pdm_id);
+int img_pdm_block_free(struct img_pdm_block *block);
+int img_pdm_block_enable_get(struct img_pdm_block *block);
+int img_pdm_block_enable_set(struct img_pdm_block *block, bool state);
+int img_pdm_block_pulse_in_get(struct img_pdm_block *block);
+int img_pdm_block_pulse_in_set(struct img_pdm_block *block,
+							unsigned int val);
+struct img_pdm_block *img_pdm_block_get(struct device *dev);
+void img_pdm_block_put(struct device *dev);
+
+#endif
-- 
1.7.0.4

[PATCH v5 4/4] DT: pdm: Add binding document for IMG PDM DAC

[Naidu Tellapati]

Add binding document for the Pulse Density Modulator (PDM) DAC present on the
Pistachio SOC.

Signed-off-by: Naidu Tellapati <Naidu.Tellapati@imgtec.com>
Signed-off-by: Arul Ramasamy <Arul.Ramasamy@imgtec.com>
---
 Documentation/devicetree/bindings/misc/img-pdm.txt |   54 ++++++++++++++++++++
 1 files changed, 54 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/misc/img-pdm.txt

diff --git a/Documentation/devicetree/bindings/misc/img-pdm.txt b/Documentation/devicetree/bindings/misc/img-pdm.txt
new file mode 100644
index 0000000..730d38a
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/img-pdm.txt
@@ -0,0 +1,54 @@
+*Imagination Technologies Pulse Density Modulator (PDM) DAC.
+
+Required properties:
+  - compatible: Must be "img,pistachio-pdm"
+  - clocks: Must contain an entry for each entry in clock-names.
+  - clock-names: Must include the following entry:
+	Required elements: "pdm"
+  - img,cr-periph: Must contain a phandle to the peripheral control
+	syscon node which contains PDM control registers.
+  - #pdm-cells: Must be 2.
+  - The first cell is the PDM channel number (valid values: 0, 1, 2, 3)
+  - The second cell is 12-bit pulse-in value
+
+Specifying PDM information for devices
+======================================
+
+1. PDM User nodes
+
+PDM properties should be named "pdms". The exact meaning of each pdms property
+is described above.
+
+	pdm-specifier : array of #pdm-cells specifying the given PDM
+						(controller specific)
+
+The following example could be used to describe a PDM-based backlight device:
+
+	pdm: pdm {
+		#pdm-cells = <2>;
+	};
+
+	[...]
+
+	bl: backlight {
+		pdms = <&pdm 2 0>;
+	};
+
+pdm-specifier typically encodes the chip-relative PDM channel number and the
+12-bit pulse-in value.
+
+2. PDM Controller nodes
+
+PDM controller nodes must specify the number of cells used for the specifier
+using the '#pdm-cells' property.
+
+An example PDM controller might look like this:
+
+Example:
+	pdm: pdm@18148000 {
+		compatible = "img,pistachio-pdm";
+		clocks = <&pdm_clk>;
+		clk-names = "pdm";
+		img,cr-periph = <&cr_periph>;
+		#pdm-cells = <2>;
+	};
-- 
1.7.0.4