Message-ID: <4306a9d5-f3b8-0695-d009-9c40f087b91d@hisilicon.com>
Date:   Tue, 13 Dec 2016 11:29:17 +0800
From:   Jian Yuan <yuanjian12@...ilicon.com>
To:     <thierry.reding@...il.com>, <robh+dt@...nel.org>,
        <mark.rutland@....com>
CC:     <linux-pwm@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <xuejiancheng@...ilicon.com>,
        <kevin.lixu@...ilicon.com>, <jalen.hsu@...ilicon.com>
Subject: Re: [PATCH v6] pwm: add pwm driver for HiSilicon BVT SOCs

Hi, Thierry,
  Are there any issues with the PWM driver below.
  I would like to request some comment and advice form you, if you had reviewed the driver code.

  With best wishes,
  Jian Yuan

On 2016/11/28 17:42, Jian Yuan wrote:
> From: yuanjian <yuanjian12@...ilicon.com>
> 
> Add PWM driver for the PWM controller found on HiSilicon BVT SOCs, like Hi3519V100, Hi3516CV300, etc.
> The PWM controller is primarily in charge of controlling P-Iris lens.
> 
> Reviewed-by: Jiancheng Xue <xuejiancheng@...ilicon.com>
> Signed-off-by: Jian Yuan <yuanjian12@...ilicon.com>
> ---
> Acked-by: Rob Herring <robh@...nel.org>
> 
> Change Log:
> v6:
> It supports polarity specified in DTB and #pwm-cells can be set to 3.
> v5:
> remove the generic compatible string "hisilicon, hibvt-pwm".
> v4:
> Add #pwm-cells in the bindings document.
> v3:
> fixed issues pointed by thierry.
> Add PWM compatible string for Hi3519V100.
> Implement .apply() function which support atomic, instead of .enable()/.disable()/.config().
> v2:
> The number of PWMs is change to be probeable based on the compatible string.
> 
>  .../devicetree/bindings/pwm/pwm-hibvt.txt          |  22 ++
>  drivers/pwm/Kconfig                                |   9 +
>  drivers/pwm/Makefile                               |   1 +
>  drivers/pwm/pwm-hibvt.c                            | 271 +++++++++++++++++++++
>  4 files changed, 302 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
>  create mode 100644 drivers/pwm/pwm-hibvt.c
> 
> diff --git a/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt b/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
> new file mode 100644
> index 0000000..fa7849d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/pwm-hibvt.txt
> @@ -0,0 +1,21 @@
> +Hisilicon PWM controller
> +
> +Required properties:
> +-compatible: should contain one SoC specific compatible string
> + The SoC specific strings supported including:
> +	"hisilicon,hi3516cv300-pwm"
> +	"hisilicon,hi3519v100-pwm"
> +- reg: physical base address and length of the controller's registers.
> +- clocks: phandle and clock specifier of the PWM reference clock.
> +- resets: phandle and reset specifier for the PWM controller reset.
> +- #pwm-cells: Should be 3. See pwm.txt in this directory for a description of
> +  the cells format.
> +
> +Example:
> +	pwm: pwm@...30000 {
> +		compatible = "hisilicon,hi3516cv300-pwm";
> +		reg = <0x12130000 0x10000>;
> +		clocks = <&crg_ctrl HI3516CV300_PWM_CLK>;
> +		resets = <&crg_ctrl 0x38 0>;
> +		#pwm-cells = <3>;
> +	};
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index c182efc..b2d7408 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -158,6 +158,15 @@ config PWM_FSL_FTM
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called pwm-fsl-ftm.
>  
> +config PWM_HIBVT
> +	tristate "HiSilicon BVT PWM support"
> +	depends on ARCH_HISI || COMPILE_TEST
> +	help
> +	  Generic PWM framework driver for HiSilicon BVT SoCs.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-hibvt.
> +
>  config PWM_IMG
>  	tristate "Imagination Technologies PWM driver"
>  	depends on HAS_IOMEM
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index dd35bc1..37ec39e 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
>  obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
>  obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
>  obj-$(CONFIG_PWM_FSL_FTM)	+= pwm-fsl-ftm.o
> +obj-$(CONFIG_PWM_HIBVT)		+= pwm-hibvt.o
>  obj-$(CONFIG_PWM_IMG)		+= pwm-img.o
>  obj-$(CONFIG_PWM_IMX)		+= pwm-imx.o
>  obj-$(CONFIG_PWM_JZ4740)	+= pwm-jz4740.o
> diff --git a/drivers/pwm/pwm-hibvt.c b/drivers/pwm/pwm-hibvt.c
> new file mode 100644
> index 0000000..d0e8f85
> --- /dev/null
> +++ b/drivers/pwm/pwm-hibvt.c
> @@ -0,0 +1,271 @@
> +/*
> + * PWM Controller Driver for HiSilicon BVT SoCs
> + *
> + * Copyright (c) 2016 HiSilicon Technologies Co., Ltd.
> + *
> + * 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/reset.h>
> +
> +#define PWM_CFG0_ADDR(x)    (((x) * 0x20) + 0x0)
> +#define PWM_CFG1_ADDR(x)    (((x) * 0x20) + 0x4)
> +#define PWM_CFG2_ADDR(x)    (((x) * 0x20) + 0x8)
> +#define PWM_CTRL_ADDR(x)    (((x) * 0x20) + 0xC)
> +
> +#define PWM_ENABLE_SHIFT    0
> +#define PWM_ENABLE_MASK     BIT(0)
> +
> +#define PWM_POLARITY_SHIFT  1
> +#define PWM_POLARITY_MASK   BIT(1)
> +
> +#define PWM_KEEP_SHIFT      2
> +#define PWM_KEEP_MASK       BIT(2)
> +
> +#define PWM_PERIOD_MASK     GENMASK(31, 0)
> +#define PWM_DUTY_MASK       GENMASK(31, 0)
> +
> +struct hibvt_pwm_chip {
> +	struct pwm_chip	chip;
> +	struct clk *clk;
> +	void __iomem *base;
> +	struct reset_control *rstc;
> +};
> +
> +struct hibvt_pwm_soc {
> +	u32 num_pwms;
> +};
> +
> +static const struct hibvt_pwm_soc pwm_soc[2] = {
> +	{ .num_pwms = 4 },
> +	{ .num_pwms = 8 },
> +};
> +
> +static inline struct hibvt_pwm_chip *to_hibvt_pwm_chip(struct pwm_chip *chip)
> +{
> +	return container_of(chip, struct hibvt_pwm_chip, chip);
> +}
> +
> +static void hibvt_pwm_set_bits(void __iomem *base, u32 offset,
> +					u32 mask, u32 data)
> +{
> +	void __iomem *address = base + offset;
> +	u32 value;
> +
> +	value = readl(address);
> +	value &= ~mask;
> +	value |= (data & mask);
> +	writel(value, address);
> +}
> +
> +static void hibvt_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
> +
> +	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
> +			PWM_ENABLE_MASK, 0x1);
> +}
> +
> +static void hibvt_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
> +
> +	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
> +			PWM_ENABLE_MASK, 0x0);
> +}
> +
> +static void hibvt_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> +					int duty_cycle_ns, int period_ns)
> +{
> +	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
> +	u32 freq, period, duty;
> +
> +	freq = div_u64(clk_get_rate(hi_pwm_chip->clk), 1000000);
> +
> +	period = div_u64(freq * period_ns, 1000);
> +	duty = div_u64(period * duty_cycle_ns, period_ns);
> +
> +	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CFG0_ADDR(pwm->hwpwm),
> +			PWM_PERIOD_MASK, period);
> +
> +	hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CFG1_ADDR(pwm->hwpwm),
> +			PWM_DUTY_MASK, duty);
> +}
> +
> +static void hibvt_pwm_set_polarity(struct pwm_chip *chip,
> +					struct pwm_device *pwm,
> +					enum pwm_polarity polarity)
> +{
> +	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
> +
> +	if (polarity == PWM_POLARITY_INVERSED)
> +		hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
> +				PWM_POLARITY_MASK, (0x1 << PWM_POLARITY_SHIFT));
> +	else
> +		hibvt_pwm_set_bits(hi_pwm_chip->base, PWM_CTRL_ADDR(pwm->hwpwm),
> +				PWM_POLARITY_MASK, (0x0 << PWM_POLARITY_SHIFT));
> +}
> +
> +static void hibvt_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
> +				struct pwm_state *state)
> +{
> +	struct hibvt_pwm_chip *hi_pwm_chip = to_hibvt_pwm_chip(chip);
> +	void __iomem *base;
> +	u32 freq, value;
> +
> +	freq = div_u64(clk_get_rate(hi_pwm_chip->clk), 1000000);
> +	base = hi_pwm_chip->base;
> +
> +	value = readl(base + PWM_CFG0_ADDR(pwm->hwpwm));
> +	state->period = div_u64(value * 1000, freq);
> +
> +	value = readl(base + PWM_CFG1_ADDR(pwm->hwpwm));
> +	state->duty_cycle = div_u64(value * 1000, freq);
> +
> +	value = readl(base + PWM_CTRL_ADDR(pwm->hwpwm));
> +	state->enabled = (PWM_ENABLE_MASK & value);
> +}
> +
> +static int hibvt_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> +				struct pwm_state *state)
> +{
> +	if (state->polarity != pwm->state.polarity)
> +		hibvt_pwm_set_polarity(chip, pwm, state->polarity);
> +
> +	if (state->period != pwm->state.period ||
> +		state->duty_cycle != pwm->state.duty_cycle)
> +		hibvt_pwm_config(chip, pwm, state->duty_cycle, state->period);
> +
> +	if (state->enabled != pwm->state.enabled) {
> +		if (state->enabled)
> +			hibvt_pwm_enable(chip, pwm);
> +		else
> +			hibvt_pwm_disable(chip, pwm);
> +	}
> +
> +	return 0;
> +}
> +
> +static struct pwm_ops hibvt_pwm_ops = {
> +	.get_state = hibvt_pwm_get_state,
> +	.apply = hibvt_pwm_apply,
> +
> +	.owner = THIS_MODULE,
> +};
> +
> +static int hibvt_pwm_probe(struct platform_device *pdev)
> +{
> +	const struct hibvt_pwm_soc *soc =
> +				of_device_get_match_data(&pdev->dev);
> +	struct hibvt_pwm_chip *pwm_chip;
> +	struct resource *res;
> +	int ret;
> +	int i;
> +
> +	pwm_chip = devm_kzalloc(&pdev->dev, sizeof(*pwm_chip), GFP_KERNEL);
> +	if (pwm_chip == NULL)
> +		return -ENOMEM;
> +
> +	pwm_chip->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(pwm_chip->clk)) {
> +		dev_err(&pdev->dev, "getting clock failed with %ld\n",
> +				PTR_ERR(pwm_chip->clk));
> +		return PTR_ERR(pwm_chip->clk);
> +	}
> +
> +	pwm_chip->chip.ops = &hibvt_pwm_ops;
> +	pwm_chip->chip.dev = &pdev->dev;
> +	pwm_chip->chip.base = -1;
> +	pwm_chip->chip.npwm = soc->num_pwms;
> +	pwm_chip->chip.of_xlate = of_pwm_xlate_with_flags;
> +	pwm_chip->chip.of_pwm_n_cells = 3;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	pwm_chip->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(pwm_chip->base))
> +		return PTR_ERR(pwm_chip->base);
> +
> +	ret = clk_prepare_enable(pwm_chip->clk);
> +	if (ret < 0)
> +		return ret;
> +
> +	pwm_chip->rstc = devm_reset_control_get(&pdev->dev, NULL);
> +	if (IS_ERR(pwm_chip->rstc)) {
> +		clk_disable_unprepare(pwm_chip->clk);
> +		return PTR_ERR(pwm_chip->rstc);
> +	}
> +
> +	reset_control_assert(pwm_chip->rstc);
> +	msleep(30);
> +	reset_control_deassert(pwm_chip->rstc);
> +
> +	ret = pwmchip_add(&pwm_chip->chip);
> +	if (ret < 0) {
> +		clk_disable_unprepare(pwm_chip->clk);
> +		return ret;
> +	}
> +
> +	for (i = 0; i < pwm_chip->chip.npwm; i++) {
> +		hibvt_pwm_set_bits(pwm_chip->base, PWM_CTRL_ADDR(i),
> +				PWM_KEEP_MASK, (0x1 << PWM_KEEP_SHIFT));
> +	}
> +
> +	platform_set_drvdata(pdev, pwm_chip);
> +
> +	return 0;
> +}
> +
> +static int hibvt_pwm_remove(struct platform_device *pdev)
> +{
> +	struct hibvt_pwm_chip *pwm_chip;
> +
> +	pwm_chip = platform_get_drvdata(pdev);
> +
> +	reset_control_assert(pwm_chip->rstc);
> +	msleep(30);
> +	reset_control_deassert(pwm_chip->rstc);
> +
> +	clk_disable_unprepare(pwm_chip->clk);
> +
> +	return pwmchip_remove(&pwm_chip->chip);
> +}
> +
> +static const struct of_device_id hibvt_pwm_of_match[] = {
> +	{ .compatible = "hisilicon,hi3516cv300-pwm", .data = &pwm_soc[0] },
> +	{ .compatible = "hisilicon,hi3519v100-pwm", .data = &pwm_soc[1] },
> +	{  }
> +};
> +MODULE_DEVICE_TABLE(of, hibvt_pwm_of_match);
> +
> +static struct platform_driver hibvt_pwm_driver = {
> +	.driver = {
> +		.name = "hibvt-pwm",
> +		.of_match_table = hibvt_pwm_of_match,
> +	},
> +	.probe = hibvt_pwm_probe,
> +	.remove	= hibvt_pwm_remove,
> +};
> +module_platform_driver(hibvt_pwm_driver);
> +
> +MODULE_AUTHOR("Jian Yuan");
> +MODULE_DESCRIPTION("HiSilicon BVT SoCs PWM driver");
> +MODULE_LICENSE("GPL");
> 

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