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Subject[PATCH V4 2/5] pwm: Add i.MX TPM PWM driver support
Date
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 V3:
- use "PWM_IMX_" as macro definition prefix and "pwm_imx_" as function prefix;
- improve the limitation txt;
- return error for configuring period/prescale fail;
- disable clock when driver probe failed and remove;
- improve module build dependency;
- introduce user_count to determine whether configuing period is allowed;
- some logic improvement for setting duty/status etc.;
---
drivers/pwm/Kconfig | 12 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-imx-tpm.c | 396 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 409 insertions(+)
create mode 100644 drivers/pwm/pwm-imx-tpm.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index a8f47df..6117fe6 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -201,6 +201,18 @@ 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 || COMPILE_TEST
+ depends on HAVE_CLK && HAS_IOMEM
+
+ 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..f108f75
--- /dev/null
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -0,0 +1,396 @@
+// 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.
+ */
+
+#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>
+
+#define PWM_IMX_TPM_GLOBAL 0x8
+#define PWM_IMX_TPM_SC 0x10
+#define PWM_IMX_TPM_CNT 0x14
+#define PWM_IMX_TPM_MOD 0x18
+#define PWM_IMX_TPM_C0SC 0x20
+#define PWM_IMX_TPM_C0V 0x24
+
+#define PWM_IMX_TPM_SC_CMOD GENMASK(4, 3)
+#define PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK BIT(3)
+#define PWM_IMX_TPM_SC_CPWMS BIT(5)
+
+#define PWM_IMX_TPM_CnSC_CHF BIT(7)
+#define PWM_IMX_TPM_CnSC_MSnB BIT(5)
+#define PWM_IMX_TPM_CnSC_MSnA BIT(4)
+#define PWM_IMX_TPM_CnSC_ELSnB BIT(3)
+#define PWM_IMX_TPM_CnSC_ELSnA BIT(2)
+
+#define PWM_IMX_TPM_SC_PS_MASK 0x7
+#define PWM_IMX_TPM_MOD_MOD_MASK 0xffff
+
+#define PWM_IMX_TPM_MAX_COUNT 0xffff
+
+#define PWM_IMX_TPM_MAX_CHANNEL_NUM 6
+
+#define PWM_IMX_TPM_CnSC(n) (PWM_IMX_TPM_C0SC + n * 0x8)
+#define PWM_IMX_TPM_CnV(n) (PWM_IMX_TPM_C0V + n * 0x8)
+
+struct imx_tpm_pwm_chip {
+ struct pwm_chip chip;
+ struct clk *clk;
+ void __iomem *base;
+ struct mutex lock;
+ u32 user_count;
+ u32 chn_config[PWM_IMX_TPM_MAX_CHANNEL_NUM];
+ bool chn_status[PWM_IMX_TPM_MAX_CHANNEL_NUM];
+};
+
+#define to_imx_tpm_pwm_chip(_chip) \
+ container_of(_chip, struct imx_tpm_pwm_chip, chip)
+
+static int pwm_imx_tpm_config_counter(struct pwm_chip *chip, u32 period)
+{
+ struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
+ u32 period_cnt, val, div, saved_cmod;
+ u64 tmp;
+
+ tmp = clk_get_rate(tpm->clk);
+ tmp *= period;
+ val = DIV_ROUND_CLOSEST_ULL(tmp, NSEC_PER_SEC);
+ if (val < PWM_IMX_TPM_MAX_COUNT)
+ div = 0;
+ else
+ div = ilog2(roundup_pow_of_two(val /
+ (PWM_IMX_TPM_MAX_COUNT + 1)));
+ if (div > PWM_IMX_TPM_SC_PS_MASK) {
+ dev_err(chip->dev,
+ "failed to find valid prescale value!\n");
+ return -EINVAL;
+ }
+
+ /* make sure counter is disabled for programming prescale */
+ val = readl(tpm->base + PWM_IMX_TPM_SC);
+ saved_cmod = val & PWM_IMX_TPM_SC_CMOD;
+ val &= ~PWM_IMX_TPM_SC_CMOD;
+ writel(val, tpm->base + PWM_IMX_TPM_SC);
+
+ /* set TPM counter prescale */
+ val = readl(tpm->base + PWM_IMX_TPM_SC);
+ val &= ~PWM_IMX_TPM_SC_PS_MASK;
+ val |= div;
+ writel(val, tpm->base + PWM_IMX_TPM_SC);
+
+ /*
+ * set period counter: according to RM, the MOD register is
+ * updated immediately when CMOD[1:0] = 2b'00 (counter disabled).
+ */
+ do_div(tmp, NSEC_PER_SEC);
+ period_cnt = DIV_ROUND_CLOSEST_ULL(tmp, 1 << div)
+ & PWM_IMX_TPM_MOD_MOD_MASK;
+ writel(period_cnt, tpm->base + PWM_IMX_TPM_MOD);
+
+ /* restore the clock mode */
+ val = readl(tpm->base + PWM_IMX_TPM_SC);
+ val |= saved_cmod;
+ writel(val, tpm->base + PWM_IMX_TPM_SC);
+
+ return 0;
+}
+
+static void pwm_imx_tpm_config(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ u32 period,
+ u32 duty_cycle,
+ enum pwm_polarity polarity)
+{
+ struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
+ u32 duty_cnt, val;
+ u64 tmp;
+
+ /* set duty counter */
+ tmp = readl(tpm->base + PWM_IMX_TPM_MOD) & PWM_IMX_TPM_MOD_MOD_MASK;
+ tmp *= duty_cycle;
+ duty_cnt = DIV_ROUND_CLOSEST_ULL(tmp, period);
+ writel(duty_cnt & PWM_IMX_TPM_MOD_MOD_MASK,
+ tpm->base + PWM_IMX_TPM_CnV(pwm->hwpwm));
+
+ /* set polarity */
+ val = readl(tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
+ val &= ~(PWM_IMX_TPM_CnSC_ELSnB | PWM_IMX_TPM_CnSC_ELSnA |
+ PWM_IMX_TPM_CnSC_MSnA);
+ val |= PWM_IMX_TPM_CnSC_MSnB;
+ val |= polarity ? PWM_IMX_TPM_CnSC_ELSnA : PWM_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 pwm_imx_tpm_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 + PWM_IMX_TPM_SC);
+ if (enable) {
+ /* restore channel config */
+ writel(tpm->chn_config[pwm->hwpwm],
+ tpm->base + PWM_IMX_TPM_CnSC(pwm->hwpwm));
+
+ /* start TPM counter anyway */
+ val |= PWM_IMX_TPM_SC_CMOD_INC_EVERY_CLK;
+ writel(val, tpm->base + PWM_IMX_TPM_SC);
+ } else {
+ /*
+ * 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.
+ */
+ /* save channel config */
+ tpm->chn_config[pwm->hwpwm] = readl(tpm->base +
+ PWM_IMX_TPM_CnSC(pwm->hwpwm));
+ /* disable channel */
+ writel(PWM_IMX_TPM_CnSC_CHF,
+ tpm->base + PWM_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 &= ~PWM_IMX_TPM_SC_CMOD;
+ writel(val, tpm->base + PWM_IMX_TPM_SC);
+ }
+ }
+
+ /* update channel statue */
+ tpm->chn_status[pwm->hwpwm] = enable;
+}
+
+static void pwm_imx_tpm_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);
+ u64 tmp;
+ u32 val, rate;
+
+ mutex_lock(&tpm->lock);
+
+ /* get period */
+ rate = clk_get_rate(tpm->clk);
+ tmp = readl(tpm->base + PWM_IMX_TPM_MOD);
+ val = readl(tpm->base + PWM_IMX_TPM_SC);
+ val &= PWM_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 + PWM_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 + PWM_IMX_TPM_CnSC(pwm->hwpwm));
+ if (val & PWM_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;
+
+ mutex_unlock(&tpm->lock);
+}
+
+static int pwm_imx_tpm_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;
+ u32 duty_cycle = state->duty_cycle;
+ int ret;
+
+ pwm_imx_tpm_get_state(chip, pwm, &curstate);
+
+ mutex_lock(&tpm->lock);
+
+ if (state->period != curstate.period) {
+ /*
+ * TPM counter is shared by multiple channels, so
+ * the prescale and period can NOT be modified when
+ * there are multiple channels used.
+ */
+ if (tpm->user_count != 1)
+ return -EBUSY;
+ ret = pwm_imx_tpm_config_counter(chip, state->period);
+ if (ret)
+ return ret;
+ }
+
+ if (!state->enabled)
+ duty_cycle = 0;
+
+ if (state->duty_cycle != curstate.duty_cycle ||
+ state->polarity != curstate.polarity)
+ pwm_imx_tpm_config(chip, pwm,
+ state->period, duty_cycle, state->polarity);
+
+ if (state->enabled != curstate.enabled)
+ pwm_imx_tpm_enable(chip, pwm, state->enabled);
+
+ mutex_unlock(&tpm->lock);
+
+ return 0;
+}
+
+static int pwm_imx_tpm_request(struct pwm_chip *chip, struct pwm_device *dev)
+{
+ struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
+
+ mutex_lock(&tpm->lock);
+ tpm->user_count++;
+ mutex_unlock(&tpm->lock);
+
+ return 0;
+}
+
+static void pwm_imx_tpm_free(struct pwm_chip *chip, struct pwm_device *dev)
+{
+ struct imx_tpm_pwm_chip *tpm = to_imx_tpm_pwm_chip(chip);
+
+ mutex_lock(&tpm->lock);
+ tpm->user_count--;
+ mutex_unlock(&tpm->lock);
+}
+
+static const struct pwm_ops imx_tpm_pwm_ops = {
+ .get_state = pwm_imx_tpm_get_state,
+ .request = pwm_imx_tpm_request,
+ .apply = pwm_imx_tpm_apply,
+ .free = pwm_imx_tpm_free,
+ .owner = THIS_MODULE,
+};
+
+static int pwm_imx_tpm_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 = PWM_IMX_TPM_MAX_CHANNEL_NUM;
+
+ mutex_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(tpm->clk);
+ }
+
+ return ret;
+}
+
+static int pwm_imx_tpm_remove(struct platform_device *pdev)
+{
+ struct imx_tpm_pwm_chip *tpm = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(tpm->clk);
+
+ return pwmchip_remove(&tpm->chip);
+}
+
+static int __maybe_unused pwm_imx_tpm_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 pwm_imx_tpm_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,
+ pwm_imx_tpm_suspend, pwm_imx_tpm_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 = pwm_imx_tpm_probe,
+ .remove = pwm_imx_tpm_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");
--
2.7.4
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