[PATCH INTERNAL v2 0/3] pwm support for Broadcom iProc SoC's

[PATCH INTERNAL v2 0/3] pwm support for Broadcom iProc SoC's

[Yendapally Reddy Dhananjaya Reddy]

This patchset contains the pwm support for the Broadcom's iProc SoC's.

The first patch provides the documentation details and the
second patch contains the controller support details. The third patch
contains the enable method for Northstar Plus SoC.

This patch series has been tested on NSP bcm958625HR board.
The pwm is not enabled for this board as the pins are open and not used.

This patch series is based on v4.6.0-rc1 and is available from github
repo: https://github.com/Broadcom/cygnus-linux.git
branch: iproc-pwm-v2

Changes since v1

Addressed the review comments from Thierry
 1. Use separate driver for iProc SoC's.

Yendapally Reddy Dhananjaya Reddy (3):
  Documentation: dt: Add Broadcom iproc pwm controller binding
  pwm: iproc: Add support for Broadcom iproc pwm controller
  ARM: dts: NSP: Add PWM Support to DT

 .../devicetree/bindings/pwm/brcm,iproc-pwm.txt     |  21 ++
 arch/arm/boot/dts/bcm-nsp.dtsi                     |   8 +
 drivers/pwm/Kconfig                                |  10 +
 drivers/pwm/Makefile                               |   1 +
 drivers/pwm/pwm-bcm-iproc.c                        | 320 +++++++++++++++++++++
 5 files changed, 360 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt
 create mode 100644 drivers/pwm/pwm-bcm-iproc.c

-- 
2.1.0

[PATCH INTERNAL v2 1/3] Documentation: dt: Add Broadcom iproc pwm controller binding

[Yendapally Reddy Dhananjaya Reddy]

Add a binding for Broadcom iproc pwm controller

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
---
 .../devicetree/bindings/pwm/brcm,iproc-pwm.txt      | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt

diff --git a/Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt b/Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt
new file mode 100644
index 0000000..21f75bb
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt
@@ -0,0 +1,21 @@
+Broadcom iProc PWM controller device tree bindings
+
+This controller has 4 channels.
+
+Required Properties :
+- compatible: must be "brcm,iproc-pwm"
+- reg: physical base address and length of the controller's registers
+- clocks: phandle + clock specifier pair for the external clock
+- #pwm-cells: Should be 3. See pwm.txt in this directory for a
+  description of the cells format.
+
+Refer to clocks/clock-bindings.txt for generic clock consumer properties.
+
+Example:
+
+pwm: pwm@18031000 {
+	compatible = "brcm,iproc-pwm";
+	reg = <0x18031000 0x28>;
+	clocks = <&osc>;
+	#pwm-cells = <3>;
+};
-- 
2.1.0

[PATCH INTERNAL v2 2/3] pwm: iproc: Add support for Broadcom iproc pwm controller

[Yendapally Reddy Dhananjaya Reddy]

Add support for Broadcom iproc pwm controller

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
---
 drivers/pwm/Kconfig         |  10 ++
 drivers/pwm/Makefile        |   1 +
 drivers/pwm/pwm-bcm-iproc.c | 320 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 331 insertions(+)
 create mode 100644 drivers/pwm/pwm-bcm-iproc.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c182efc..d298ebd 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -74,6 +74,16 @@ config PWM_ATMEL_TCB
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-atmel-tcb.
 
+config PWM_BCM_IPROC
+	tristate "iProc PWM support"
+	depends on ARCH_BCM_IPROC
+	help
+	  Generic PWM framework driver for Broadcom iProc PWM block. This
+	  block is used in Broadcom iProc SoC's.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-bcm-iproc.
+
 config PWM_BCM_KONA
 	tristate "Kona PWM support"
 	depends on ARCH_BCM_MOBILE
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index dd35bc1..a196d79 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500)	+= pwm-ab8500.o
 obj-$(CONFIG_PWM_ATMEL)		+= pwm-atmel.o
 obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM)	+= pwm-atmel-hlcdc.o
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
+obj-$(CONFIG_PWM_BCM_IPROC)	+= pwm-bcm-iproc.o
 obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o
 obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o
 obj-$(CONFIG_PWM_BERLIN)	+= pwm-berlin.o
diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
new file mode 100644
index 0000000..3ba3ca5
--- /dev/null
+++ b/drivers/pwm/pwm-bcm-iproc.c
@@ -0,0 +1,320 @@
+/*
+ * Copyright (C) 2016 Broadcom
+ *
+ * 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.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define IPROC_PWM_CTRL_OFFSET			(0x00)
+#define IPROC_PWM_CTRL_TYPE_SHIFT(chan)		(15 + (chan))
+#define IPROC_PWM_CTRL_POLARITY_SHIFT(chan)	(8 + (chan))
+#define IPROC_PWM_CTRL_EN_SHIFT(chan)		(chan)
+
+#define IPROC_PWM_PERIOD_OFFSET(chan)		(0x04 + ((chan) << 3))
+#define IPROC_PWM_PERIOD_MIN			(0x02)
+#define IPROC_PWM_PERIOD_MAX			(0xffff)
+
+#define IPROC_PWM_DUTY_CYCLE_OFFSET(chan)	(0x08 + ((chan) << 3))
+#define IPROC_PWM_DUTY_CYCLE_MIN		(0x00)
+#define IPROC_PWM_DUTY_CYCLE_MAX		(0xffff)
+
+#define IPROC_PWM_PRESCALE_OFFSET		(0x24)
+#define IPROC_PWM_PRESCALE_BITS			(0x06)
+#define IPROC_PWM_PRESCALE_SHIFT(chan)		((3 - (chan)) *	\
+						IPROC_PWM_PRESCALE_BITS)
+#define IPROC_PWM_PRESCALE_MASK(chan)		(IPROC_PWM_PRESCALE_MAX << \
+						IPROC_PWM_PRESCALE_SHIFT(chan))
+#define IPROC_PWM_PRESCALE_MIN			(0x00)
+#define IPROC_PWM_PRESCALE_MAX			(0x3f)
+
+#define IPROC_PWM_CHANNEL_COUNT			(0x04)
+
+struct iproc_pwmc {
+	struct pwm_chip chip;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *_chip)
+{
+	return container_of(_chip, struct iproc_pwmc, chip);
+}
+
+static void iproc_pwmc_unset_enable_bit(struct iproc_pwmc *ip, u32 chan)
+{
+	unsigned int value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(chan));
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	/*
+	 * There must be a min 400ns delay between clearing trigger and setting
+	 * it. Failing to do this may result in no PWM signal.
+	 */
+	ndelay(400);
+}
+
+static void iproc_pwmc_set_enable_bit(struct iproc_pwmc *ip, unsigned int chan)
+{
+	unsigned int value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	/* Set trigger bit to apply new settings */
+	value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(chan);
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	/* Trigger bit must be held high for at least 400 ns. */
+	ndelay(400);
+}
+
+static int iproc_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			     int duty_ns, int period_ns)
+{
+	unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	unsigned int value, chan = pwm->hwpwm;
+	unsigned long period_cnt, duty_cnt;
+	u64 val, div, rate;
+
+	rate = clk_get_rate(ip->clk);
+	if (!rate) {
+		dev_err(pwm->chip->dev, "pwm clock has no frequency\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Find period count, duty count and prescale to suit duty_ns and
+	 * period_ns. This is done according to formulas described below:
+	 *
+	 * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
+	 * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+	 *
+	 * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
+	 * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
+	 */
+	while (1) {
+		div = 1000000000;
+		div *= 1 + prescale;
+		val = rate * period_ns;
+		period_cnt = div64_u64(val, div);
+		val = rate * duty_ns;
+		duty_cnt = div64_u64(val, div);
+
+		if (period_cnt < IPROC_PWM_PERIOD_MIN ||
+				duty_cnt < IPROC_PWM_DUTY_CYCLE_MIN)
+			return -EINVAL;
+
+		if (period_cnt <= IPROC_PWM_PERIOD_MAX &&
+				 duty_cnt <= IPROC_PWM_DUTY_CYCLE_MAX)
+			break;
+
+		/* Otherwise, increase prescale and recalculate counts */
+		if (++prescale > IPROC_PWM_PRESCALE_MAX)
+			return -EINVAL;
+	}
+
+	/*
+	 * Don't apply settings if disabled. The period and duty cycle are
+	 * always calculated above to ensure the new values are
+	 * validated immediately instead of on enable.
+	 */
+	if (pwm_is_enabled(pwm)) {
+		iproc_pwmc_unset_enable_bit(ip, chan);
+
+		value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+		value &= ~IPROC_PWM_PRESCALE_MASK(chan);
+		value |= prescale << IPROC_PWM_PRESCALE_SHIFT(chan);
+
+		writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
+		writel(period_cnt, ip->base + IPROC_PWM_PERIOD_OFFSET(chan));
+		writel(duty_cnt, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(chan));
+
+		iproc_pwmc_set_enable_bit(ip, chan);
+	}
+
+	return 0;
+}
+
+static int iproc_pwmc_set_polarity(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   enum pwm_polarity polarity)
+{
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	unsigned int chan = pwm->hwpwm;
+	unsigned int value;
+	int ret;
+
+	ret = clk_prepare_enable(ip->clk);
+	if (ret < 0) {
+		dev_err(chip->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	iproc_pwmc_unset_enable_bit(ip, chan);
+
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+	if (polarity == PWM_POLARITY_NORMAL)
+		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan);
+	else
+		value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan));
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	iproc_pwmc_set_enable_bit(ip, chan);
+
+	clk_disable_unprepare(ip->clk);
+
+	return 0;
+}
+
+static int iproc_pwmc_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	int ret;
+
+	ret = clk_prepare_enable(ip->clk);
+	if (ret < 0) {
+		dev_err(chip->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	ret = iproc_pwmc_config(chip, pwm, pwm_get_duty_cycle(pwm),
+						pwm_get_period(pwm));
+	if (ret < 0) {
+		clk_disable_unprepare(ip->clk);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void iproc_pwmc_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+	unsigned int chan = pwm->hwpwm;
+	unsigned int value;
+
+	iproc_pwmc_unset_enable_bit(ip, chan);
+
+	writel(0, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(chan));
+	writel(0, ip->base + IPROC_PWM_PERIOD_OFFSET(chan));
+
+	/* Set prescale to 0 for this channel */
+	value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+	value &= ~IPROC_PWM_PRESCALE_MASK(chan);
+	writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
+
+	iproc_pwmc_set_enable_bit(ip, chan);
+
+	clk_disable_unprepare(ip->clk);
+}
+
+static const struct pwm_ops iproc_pwm_ops = {
+	.config = iproc_pwmc_config,
+	.set_polarity = iproc_pwmc_set_polarity,
+	.enable = iproc_pwmc_enable,
+	.disable = iproc_pwmc_disable,
+	.owner = THIS_MODULE,
+};
+
+static int iproc_pwmc_probe(struct platform_device *pdev)
+{
+	struct iproc_pwmc *ip;
+	struct resource *res;
+	unsigned int value;
+	unsigned int chan;
+	int ret;
+
+	ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);
+	if (ip == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ip);
+
+	ip->chip.dev = &pdev->dev;
+	ip->chip.ops = &iproc_pwm_ops;
+	ip->chip.base = -1;
+	ip->chip.npwm = IPROC_PWM_CHANNEL_COUNT;
+	ip->chip.of_xlate = of_pwm_xlate_with_flags;
+	ip->chip.of_pwm_n_cells = 3;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	ip->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ip->base))
+		return PTR_ERR(ip->base);
+
+	ip->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ip->clk)) {
+		dev_err(&pdev->dev, "failed to get clock: %ld\n",
+			PTR_ERR(ip->clk));
+		return PTR_ERR(ip->clk);
+	}
+
+	ret = clk_prepare_enable(ip->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	/* Set full drive and normal polarity for all channels */
+	value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+	for (chan = 0; chan < ip->chip.npwm; chan++) {
+		value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(chan));
+		value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan);
+	}
+	writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+	clk_disable_unprepare(ip->clk);
+
+	ret = pwmchip_add(&ip->chip);
+	if (ret < 0)
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+
+	return ret;
+}
+
+static int iproc_pwmc_remove(struct platform_device *pdev)
+{
+	struct iproc_pwmc *ip = platform_get_drvdata(pdev);
+	unsigned int chan;
+
+	for (chan = 0; chan < ip->chip.npwm; chan++)
+		if (pwm_is_enabled(&ip->chip.pwms[chan]))
+			clk_disable_unprepare(ip->clk);
+
+	return pwmchip_remove(&ip->chip);
+}
+
+static const struct of_device_id bcm_iproc_pwmc_dt[] = {
+	{ .compatible = "brcm,iproc-pwm" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
+
+static struct platform_driver iproc_pwmc_driver = {
+	.driver = {
+		.name = "bcm-iproc-pwm",
+		.of_match_table = bcm_iproc_pwmc_dt,
+	},
+	.probe = iproc_pwmc_probe,
+	.remove = iproc_pwmc_remove,
+};
+module_platform_driver(iproc_pwmc_driver);
+
+MODULE_AUTHOR("Broadcom Corporation");
+MODULE_DESCRIPTION("Broadcom iProc PWM driver");
+MODULE_LICENSE("GPL v2");
-- 
2.1.0

[PATCH INTERNAL v2 3/3] ARM: dts: NSP: Add PWM Support to DT

[Yendapally Reddy Dhananjaya Reddy]

Add PWM support to the device tree for the Broadcom Northstar Plus SoC.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
---
 arch/arm/boot/dts/bcm-nsp.dtsi | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm/boot/dts/bcm-nsp.dtsi b/arch/arm/boot/dts/bcm-nsp.dtsi
index def9e78..f9c8341 100644
--- a/arch/arm/boot/dts/bcm-nsp.dtsi
+++ b/arch/arm/boot/dts/bcm-nsp.dtsi
@@ -206,6 +206,14 @@
 			brcm,nand-has-wp;
 		};
 
+		pwm: pwm@31000 {
+			compatible = "brcm,iproc-pwm";
+			reg = <0x31000 0x28>;
+			clocks = <&osc>;
+			#pwm-cells = <3>;
+			status = "disabled";
+		};
+
 		ccbtimer0: timer@34000 {
 			compatible = "arm,sp804";
 			reg = <0x34000 0x1000>;
-- 
2.1.0

Re: [PATCH INTERNAL v2 1/3] Documentation: dt: Add Broadcom iproc pwm controller binding

[Rob Herring]

Am I supposed to ignore since this is "internal"?

On Wed, May 18, 2016 at 02:53:59AM -0400, Yendapally Reddy Dhananjaya Reddy wrote:
> Add a binding for Broadcom iproc pwm controller
> 
> Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
> ---
>  .../devicetree/bindings/pwm/brcm,iproc-pwm.txt      | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt

Acked-by: Rob Herring <robh@kernel.org>

Re: [PATCH INTERNAL v2 1/3] Documentation: dt: Add Broadcom iproc pwm controller binding

[Scott Branden]

Hi Rob,

On 16-05-18 03:15 PM, Rob Herring wrote:
> Am I supposed to ignore since this is "internal"?
The "INTERNAL" was supposed to be removed after internal review before 
sending out to the public mailing list.

Also, Yendapally's git email config was not setup properly so some are 
tagging the patchset as spam.

Other than that, everything is fine with the PATCH sent out to the open 
source community :)

I'm sure Yendapally will send out an updated version with those items 
corrected (and can add your Acked-by now).

Thanks,
  Scott

>
> On Wed, May 18, 2016 at 02:53:59AM -0400, Yendapally Reddy Dhananjaya Reddy wrote:
>> Add a binding for Broadcom iproc pwm controller
>>
>> Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
>> ---
>>   .../devicetree/bindings/pwm/brcm,iproc-pwm.txt      | 21 +++++++++++++++++++++
>>   1 file changed, 21 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/pwm/brcm,iproc-pwm.txt
>
> Acked-by: Rob Herring <robh@kernel.org>
>