lkml.org 
[lkml]   [2019]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH V3 2/5] pwm: Add i.MX TPM PWM driver support
Date


On 14.03.2019 08:27, Anson Huang wrote:
> i.MX7ULP has TPM(Low Power Timer/Pulse Width Modulation Module)
> inside, add TPM PWM driver support.
>
> Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> ---
> Changes since V2:
> - Add "IMX_" as prefix to macro define as TPM is already used;
> - Use macro define for channel registers address instead of calculation in everywhere.
> - Add limitations statement in copyright.
> ---
> drivers/pwm/Kconfig | 10 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-imx-tpm.c | 343 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 354 insertions(+)
> create mode 100644 drivers/pwm/pwm-imx-tpm.c
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index a8f47df..c1cbb43 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -201,6 +201,16 @@ config PWM_IMX
> To compile this driver as a module, choose M here: the module
> will be called pwm-imx.
>
> +config PWM_IMX_TPM
> + tristate "i.MX TPM PWM support"
> + depends on ARCH_MXC
> + help
> + Generic PWM framework driver for i.MX7ULP TPM module, TPM's full
> + name is Low Power Timer/Pulse Width Modulation Module.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-imx-tpm.
> +
> config PWM_JZ4740
> tristate "Ingenic JZ47xx PWM support"
> depends on MACH_INGENIC
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 9c676a0..64e036c 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -18,6 +18,7 @@ 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-$(CONFIG_PWM_IMX_TPM) += pwm-imx-tpm.o
> obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
> obj-$(CONFIG_PWM_LP3943) += pwm-lp3943.o
> obj-$(CONFIG_PWM_LPC18XX_SCT) += pwm-lpc18xx-sct.o
> diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
> new file mode 100644
> index 0000000..cdb29f6
> --- /dev/null
> +++ b/drivers/pwm/pwm-imx-tpm.c
> @@ -0,0 +1,343 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2018-2019 NXP.
> + *
> + * Limitations:
> + * - The TPM counter and period counter are shared between
> + * multiple channels, so all channels should use same period
> + * settings.
> + * - When a channel is disabled, its polarity settings will be
> + * saved and its output will be disabled by clearing polarity
> + * setting, when channel is enabled, polarity settings will be
> + * restored and output will be enabled again.
> + * - ONLY when all channels are disabled, then TPM counter will
> + * be disabled.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/log2.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +
> +#define IMX_TPM_GLOBAL 0x8
> +#define IMX_TPM_SC 0x10
> +#define IMX_TPM_CNT 0x14
> +#define IMX_TPM_MOD 0x18
> +#define IMX_TPM_C0SC 0x20
> +#define IMX_TPM_C0V 0x24
> +
> +#define IMX_TPM_SC_CMOD_SHIFT 3
> +#define IMX_TPM_SC_CMOD_MASK GENMASK(4, 3)
> +#define IMX_TPM_SC_CPWMS BIT(5)
> +
> +#define IMX_TPM_CnSC_CHF BIT(7)
> +#define IMX_TPM_CnSC_MSnB BIT(5)
> +#define IMX_TPM_CnSC_MSnA BIT(4)
> +#define IMX_TPM_CnSC_ELSnB BIT(3)
> +#define IMX_TPM_CnSC_ELSnA BIT(2)
> +
> +#define IMX_TPM_SC_PS_MASK 0x7
> +#define IMX_TPM_MOD_MOD_MASK 0xffff
> +
> +#define IMX_TPM_COUNT_MAX 0xffff
> +
> +#define IMX_TPM_DEFAULT_PWM_CHANNEL_NUM 2
> +
> +#define IMX_TPM_CnSC(n) (IMX_TPM_C0SC + n * 0x8)
> +#define IMX_TPM_CnV(n) (IMX_TPM_C0V + n * 0x8)
> +
> +struct imx_tpm_pwm_chip {
> + struct pwm_chip chip;
> + struct clk *clk;
> + void __iomem *base;
> + spinlock_t lock;
> + u32 chn_config[IMX_TPM_DEFAULT_PWM_CHANNEL_NUM];
> + bool chn_status[IMX_TPM_DEFAULT_PWM_CHANNEL_NUM];
> +};
> +
> +#define to_imx_tpm_pwm_chip(_chip) container_of(_chip, struct imx_tpm_pwm_chip, chip)
> +
> +static void imx_tpm_pwm_config_counter(struct pwm_chip *chip, u32 period)
> +{
> + struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
> + unsigned int period_cnt;
> + u32 val, div;
> + u64 tmp;
> +
> + tmp = clk_get_rate(tpm->clk);
> + tmp *= period;
> + val = DIV_ROUND_CLOSEST_ULL(tmp, NSEC_PER_SEC);
> + if (val < IMX_TPM_COUNT_MAX)
> + div = 0;
> + else
> + div = ilog2(roundup_pow_of_two(val / IMX_TPM_COUNT_MAX));
> + if (div > IMX_TPM_SC_PS_MASK) {
> + dev_err(chip->dev,
> + "failed to find valid prescale value!\n");
> + return;
> + }
> + /* set TPM counter prescale */
> + val = readl(tpm->base + IMX_TPM_SC);
> + val &= ~IMX_TPM_SC_PS_MASK;
> + val |= div;
> + writel(val, tpm->base + IMX_TPM_SC);
> +
> + /* set period counter */
> + do_div(tmp, NSEC_PER_SEC);
> + period_cnt = DIV_ROUND_CLOSEST_ULL(tmp, 1 << div);
> + writel(period_cnt & IMX_TPM_MOD_MOD_MASK, tpm->base + IMX_TPM_MOD);
> +}
> +
> +static void imx_tpm_pwm_config(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
> + static bool tpm_cnt_initialized;
> + unsigned int duty_cnt;
> + u32 val;
> + u64 tmp;
> +
> + /*
> + * TPM counter is shared by multi channels, let's make it to be
> + * ONLY first channel can config TPM counter's precale and period
> + * count.
> + */
> + if (!tpm_cnt_initialized) {
> + imx_tpm_pwm_config_counter(chip, state->period);
> + tpm_cnt_initialized = true;
> + }
> +
> + /* set duty counter */
> + tmp = readl(tpm->base + IMX_TPM_MOD) & IMX_TPM_MOD_MOD_MASK;
> + tmp *= state->duty_cycle;
> + duty_cnt = DIV_ROUND_CLOSEST_ULL(tmp, state->period);
> + writel(duty_cnt & IMX_TPM_MOD_MOD_MASK,
> + tpm->base + IMX_TPM_CnV(pwm->hwpwm));
> +
> + /* set polarity */
> + val = readl(tpm->base + IMX_TPM_CnSC(pwm->hwpwm));
> + val &= ~(IMX_TPM_CnSC_ELSnB | IMX_TPM_CnSC_ELSnA | IMX_TPM_CnSC_MSnA);
> + val |= IMX_TPM_CnSC_MSnB;
> + val |= state->polarity ? IMX_TPM_CnSC_ELSnA : IMX_TPM_CnSC_ELSnB;
> + /*
> + * polarity settings will enabled/disable output statue
> + * immediately, so here ONLY save the config and will be
> + * written into register when channel is enabled/disabled.
> + */
> + tpm->chn_config[pwm->hwpwm] = val;
> +}
> +
> +static void imx_tpm_pwm_enable(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + bool enable)
> +{
> + struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
> + u32 val, i;
> +
> + val = readl(tpm->base + IMX_TPM_SC);
> + if (enable) {
> + /* restore channel config */
> + writel(tpm->chn_config[pwm->hwpwm],
> + tpm->base + IMX_TPM_CnSC(pwm->hwpwm));
> +
> + /* start TPM counter anyway */
> + val |= 0x1 << IMX_TPM_SC_CMOD_SHIFT;
> + writel(val, tpm->base + IMX_TPM_SC);
> + } else {
> + /* save channel config */
> + tpm->chn_config[pwm->hwpwm] = readl(tpm->base +
> + IMX_TPM_CnSC(pwm->hwpwm));
> + /* disable channel */
> + writel(IMX_TPM_CnSC_CHF, tpm->base + IMX_TPM_CnSC(pwm->hwpwm));
> +
> + for (i = 0; i < chip->npwm; i++)
> + if (i != pwm->hwpwm && tpm->chn_status[i])
> + break;
> + if (i == chip->npwm) {
> + /* stop TPM counter since all channels are disabled */
> + val &= ~IMX_TPM_SC_CMOD_MASK;
> + writel(val, tpm->base + IMX_TPM_SC);
> + }
> + }
> +
> + /* update channel statue */
> + tpm->chn_status[pwm->hwpwm] = enable;
> +}
> +
> +static void imx_tpm_pwm_get_state(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
> + unsigned long rate, flags;
> + u64 tmp;
> + u32 val;
> +
> + spin_lock_irqsave(&tpm->lock, flags);
> +
> + /* get period */
> + rate = clk_get_rate(tpm->clk);
> + tmp = readl(tpm->base + IMX_TPM_MOD);
> + val = readl(tpm->base + IMX_TPM_SC);
> + val &= IMX_TPM_SC_PS_MASK;
> + tmp *= (1 << val) * NSEC_PER_SEC;
> + state->period = DIV_ROUND_CLOSEST_ULL(tmp, rate);
> +
> + /* get duty cycle */
> + tmp = readl(tpm->base + IMX_TPM_CnV(pwm->hwpwm));
> + tmp *= (1 << val) * NSEC_PER_SEC;
> + state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, rate);
> +
> + /* get polarity */
> + val = readl(tpm->base + IMX_TPM_CnSC(pwm->hwpwm));
> + if (val & IMX_TPM_CnSC_ELSnA)
> + state->polarity = PWM_POLARITY_INVERSED;
> + else
> + state->polarity = PWM_POLARITY_NORMAL;
> +
> + /* get channel status */
> + state->enabled = tpm->chn_status[pwm->hwpwm] ? true : false;
> +
> + spin_unlock_irqrestore(&tpm->lock, flags);
> +}
> +
> +static int imx_tpm_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + struct pwm_state *state)
> +{
> + struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
> + struct pwm_state curstate;
> + unsigned long flags;
> +
> + imx_tpm_pwm_get_state(chip, pwm, &curstate);
> +
> + spin_lock_irqsave(&tpm->lock, flags);
> +
> + if (state->period != curstate.period ||
> + state->duty_cycle != curstate.duty_cycle ||
> + state->polarity != curstate.polarity)
> + imx_tpm_pwm_config(chip, pwm, state);
> +
> + if (state->enabled != curstate.enabled)
> + imx_tpm_pwm_enable(chip, pwm, state->enabled);
> +
> + spin_unlock_irqrestore(&tpm->lock, flags);
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops imx_tpm_pwm_ops = {
> + .get_state = imx_tpm_pwm_get_state,
> + .apply = imx_tpm_pwm_apply,
> + .owner = THIS_MODULE,
> +};
> +
> +static int imx_tpm_pwm_probe(struct platform_device *pdev)
> +{
> + struct imx_tpm_pwm_chip *tpm;
> + struct resource *res;
> + int ret;
> +
> + tpm = devm_kzalloc(&pdev->dev, sizeof(*tpm), GFP_KERNEL);
> + if (!tpm)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, tpm);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + tpm->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(tpm->base)) {
> + ret = PTR_ERR(tpm->base);
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "pwm ioremap failed %d\n", ret);
> + return ret;
> + }
> +
> + tpm->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(tpm->clk)) {
> + ret = PTR_ERR(tpm->clk);
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "failed to get pwm clk %d\n", ret);
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(tpm->clk);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "failed to prepare or enable clk %d\n", ret);
> + return ret;
> + }
> +
> + tpm->chip.dev = &pdev->dev;
> + tpm->chip.ops = &imx_tpm_pwm_ops;
> + tpm->chip.base = -1;
> + tpm->chip.npwm = IMX_TPM_DEFAULT_PWM_CHANNEL_NUM;
> +
> + spin_lock_init(&tpm->lock);
> +
> + ret = pwmchip_add(&tpm->chip);
> + if (ret)
> + dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);

clk_disable_unprepare() in case of failure? Although I would use
clk_prepare()/clk_unprepare() in probe and clk_prepare_enable() only when
PWM is active.

> +
> + return ret;
> +}
> +
> +static int imx_tpm_pwm_remove(struct platform_device *pdev)
> +{
> + struct imx_tpm_pwm_chip *tpm = platform_get_drvdata(pdev);
> +

Ditto

> + return pwmchip_remove(&tpm->chip);
> +}
> +
> +static int __maybe_unused imx_tpm_pwm_suspend(struct device *dev)
> +{
> + struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);
> +
> + clk_disable_unprepare(tpm->clk);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused imx_tpm_pwm_resume(struct device *dev)
> +{
> + struct imx_tpm_pwm_chip *tpm = dev_get_drvdata(dev);
> + int ret = clk_prepare_enable(tpm->clk);
> +
> + if (ret)
> + dev_err(dev,
> + "failed to prepare or enable clk %d\n", ret);
> +
> + return ret;
> +};
> +
> +static SIMPLE_DEV_PM_OPS(imx_tpm_pwm_pm,
> + imx_tpm_pwm_suspend, imx_tpm_pwm_resume);
> +
> +static const struct of_device_id imx_tpm_pwm_dt_ids[] = {
> + { .compatible = "fsl,imx-tpm-pwm", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, imx_tpm_pwm_dt_ids);
> +
> +static struct platform_driver imx_tpm_pwm_driver = {
> + .driver = {
> + .name = "imx-tpm-pwm",
> + .of_match_table = imx_tpm_pwm_dt_ids,
> + .pm = &imx_tpm_pwm_pm,
> + },
> + .probe = imx_tpm_pwm_probe,
> + .remove = imx_tpm_pwm_remove,
> +};
> +module_platform_driver(imx_tpm_pwm_driver);
> +
> +MODULE_AUTHOR("Anson Huang <Anson.Huang@nxp.com>");
> +MODULE_DESCRIPTION("i.MX TPM PWM Driver");
> +MODULE_LICENSE("GPL v2");
>
\
 
 \ /
  Last update: 2019-03-14 10:41    [W:0.116 / U:2.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site