The RZ/V2{M, MA} PWM Timer supports the following functions:
* The PWM has 24-bit counters which operate at PWM_CLK (48 MHz).
* The frequency division ratio for internal counter operation is
selectable as PWM_CLK divided by 1, 16, 256, or 2048.
* The period as well as the duty cycle is adjustable.
* The low-level and high-level order of the PWM signals can be
inverted.
* The duty cycle of the PWM signal is selectable in the range from
0 to 100%.
* The minimum resolution is 20.83 ns.
* Three interrupt sources: Rising and falling edges of the PWM signal
and clearing of the counter
* Counter operation and the bus interface are asynchronous and both
can operate independently of the magnitude relationship of the
respective clock periods.
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v3->v4:
* Documented the hardware properties in "Limitations" section
* Dropped the macros F2CYCLE_NSEC, U24_MASK and U24_MAX.
* Added RZV2M_PWMCYC_PERIOD macro for U24_MAX
* Dropped rzv2m_pwm_freq_div variable and started using 1 << (4 * i) for
calculating divider as it is power of 16.
* Reordered the functions to have rzv2m_pwm_config() directly before
rzv2m_pwm_apply().
* Improved the logic for calculating period and duty cycle in config()
* Merged multiple RZV2M_PWMCTR register writes to a single write in config()
* replaced pwm_is_enabled()->pwm->state.enabled
* Avoided assigning bit value as enum pwm_polarity instead used enum constant.
* Fixed various issues in probe error path.
* Updated the logic for PWM cycle setting register
* A 100% duty cycle is only possible with PWMLOW > PWMCYC. So restricting
PWMCYC values < 0xffffff
* The native polarity of the hardware is inverted (i.e. it starts with the
* low part). So switched the inversion bit handling.
v2->v3:
* Added return code for rzv2m_pwm_get_state()
* Added comment in rzv2m_pwm_reset_assert_pm_disable()
v1->v2:
* Replaced devm_reset_control_get_optional_shared->devm_reset_control_get_shared
---
drivers/pwm/Kconfig | 11 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-rzv2m.c | 436 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 448 insertions(+)
create mode 100644 drivers/pwm/pwm-rzv2m.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index dae023d783a2..31cdc9dae3c5 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -473,6 +473,17 @@ config PWM_RENESAS_TPU
To compile this driver as a module, choose M here: the module
will be called pwm-renesas-tpu.
+config PWM_RZV2M
+ tristate "Renesas RZ/V2M PWM support"
+ depends on ARCH_R9A09G011 || COMPILE_TEST
+ depends on HAS_IOMEM
+ help
+ This driver exposes the PWM controller found in Renesas
+ RZ/V2M like chips through the PWM API.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-rzv2m.
+
config PWM_ROCKCHIP
tristate "Rockchip PWM support"
depends on ARCH_ROCKCHIP || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 7bf1a29f02b8..a95aabae9115 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_RASPBERRYPI_POE) += pwm-raspberrypi-poe.o
obj-$(CONFIG_PWM_RCAR) += pwm-rcar.o
obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
+obj-$(CONFIG_PWM_RZV2M) += pwm-rzv2m.o
obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
diff --git a/drivers/pwm/pwm-rzv2m.c b/drivers/pwm/pwm-rzv2m.c
new file mode 100644
index 000000000000..516e875d6285
--- /dev/null
+++ b/drivers/pwm/pwm-rzv2m.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/V2M PWM Timer (PWM) driver
+ *
+ * Copyright (C) 2022 Renesas Electronics Corporation
+ *
+ * Hardware manual for this IP can be found here
+ * https://www.renesas.com/in/en/document/mah/rzv2m-users-manual-hardware?language=en
+ *
+ * Limitations:
+ * - If the PWMLOW value is changed during PWM operation, the changed
+ * value is reflected in the next PWM cycle.
+ * - The duty cycle can be changed only by modifying the PWMLOW register
+ * value and changing the pulse width at low level. The duty cycle becomes
+ * 0% for the low width when the value of the PWMLOW register is 0x0h
+ * and 100% for the low width when the value of the PWMLOW > PWMCYC.
+ * - To change the setting value of the PWM cycle setting register
+ * (PWMm_PWMCYC), set the PWME bit of the PWM control register (PWMm_PWMCTR)
+ * to 0b and stop the counter operation. If it is changed during counter
+ * operation, PWM output may not be performed correctly.
+ * - The registers other than the PWM interrupt register (PWMINT) are always
+ * synchronized with PWM_CLK at regular intervals. It takes some time
+ * (Min: 2 × PCLK + 4 × PWM_CLK to Max: 6 × PCLK + 9 × PWM_CLK) for the
+ * value set in the register to be reflected in the PWM circuit because
+ * there is a synchronizer between the register and the PWM circuit.
+ * - The native polarity of the hardware is inverted (i.e. it starts with the
+ * low part).
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+#include <linux/time.h>
+
+#define RZV2M_PWMCTR 0x0
+#define RZV2M_PWMCYC 0x4
+#define RZV2M_PWMLOW 0x8
+#define RZV2M_PWMCNT 0xc
+
+#define RZV2M_PWMCTR_PWMPS GENMASK(17, 16)
+#define RZV2M_PWMCTR_PWMHL BIT(3)
+#define RZV2M_PWMCTR_PWMTM BIT(2)
+#define RZV2M_PWMCTR_PWME BIT(1)
+
+#define RZV2M_PWMCYC_PERIOD GENMASK(23, 0)
+
+struct rzv2m_pwm_chip {
+ struct pwm_chip chip;
+ void __iomem *mmio;
+ struct reset_control *rstc;
+ struct clk *apb_clk;
+ struct clk *pwm_clk;
+ unsigned long rate;
+ unsigned long delay;
+};
+
+static inline struct rzv2m_pwm_chip *to_rzv2m_pwm_chip(struct pwm_chip *chip)
+{
+ return container_of(chip, struct rzv2m_pwm_chip, chip);
+}
+
+static void rzv2m_pwm_wait_delay(struct rzv2m_pwm_chip *chip)
+{
+ /* delay timer when change the setting register */
+ ndelay(chip->delay);
+}
+
+static void rzv2m_pwm_write(struct rzv2m_pwm_chip *rzv2m_pwm, u32 reg, u32 data)
+{
+ writel(data, rzv2m_pwm->mmio + reg);
+}
+
+static u32 rzv2m_pwm_read(struct rzv2m_pwm_chip *rzv2m_pwm, u32 reg)
+{
+ return readl(rzv2m_pwm->mmio + reg);
+}
+
+static void rzv2m_pwm_modify(struct rzv2m_pwm_chip *rzv2m_pwm, u32 reg, u32 clr,
+ u32 set)
+{
+ rzv2m_pwm_write(rzv2m_pwm, reg,
+ (rzv2m_pwm_read(rzv2m_pwm, reg) & ~clr) | set);
+}
+
+static u8 rzv2m_pwm_calculate_prescale(struct rzv2m_pwm_chip *rzv2m_pwm,
+ u64 period_cycles)
+{
+ u32 prescaled_period_cycles;
+ u8 prescale;
+
+ prescaled_period_cycles = period_cycles >> 24;
+ if (prescaled_period_cycles >= 256)
+ prescale = 3;
+ else
+ prescale = (fls(prescaled_period_cycles) + 3) / 4;
+
+ return prescale;
+}
+
+static bool rzv2m_pwm_is_ch_enabled(struct rzv2m_pwm_chip *rzv2m_pwm)
+{
+ return !!(rzv2m_pwm_read(rzv2m_pwm, RZV2M_PWMCTR) & RZV2M_PWMCTR_PWME);
+}
+
+static int rzv2m_pwm_enable(struct rzv2m_pwm_chip *rzv2m_pwm)
+{
+ int rc;
+
+ rc = pm_runtime_resume_and_get(rzv2m_pwm->chip.dev);
+ if (rc)
+ return rc;
+
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWME,
+ RZV2M_PWMCTR_PWME);
+ rzv2m_pwm_wait_delay(rzv2m_pwm);
+
+ return 0;
+}
+
+static void rzv2m_pwm_disable(struct rzv2m_pwm_chip *rzv2m_pwm)
+{
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWME, 0);
+ rzv2m_pwm_wait_delay(rzv2m_pwm);
+
+ pm_runtime_put_sync(rzv2m_pwm->chip.dev);
+}
+
+static int rzv2m_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = to_rzv2m_pwm_chip(chip);
+ u8 prescale;
+ u32 val;
+
+ pm_runtime_get_sync(chip->dev);
+ val = rzv2m_pwm_read(rzv2m_pwm, RZV2M_PWMCTR);
+ state->enabled = FIELD_GET(RZV2M_PWMCTR_PWME, val);
+ state->polarity = FIELD_GET(RZV2M_PWMCTR_PWMHL, val) ?
+ PWM_POLARITY_NORMAL : PWM_POLARITY_INVERSED;
+ prescale = FIELD_GET(RZV2M_PWMCTR_PWMPS, val);
+ val = rzv2m_pwm_read(rzv2m_pwm, RZV2M_PWMCYC);
+ if (val)
+ val += 1;
+ state->period = DIV_ROUND_UP_ULL(NSEC_PER_SEC * (u64)val << (4 * prescale),
+ rzv2m_pwm->rate);
+
+ val = rzv2m_pwm_read(rzv2m_pwm, RZV2M_PWMLOW);
+ if (val)
+ val += 1;
+ state->duty_cycle = DIV_ROUND_UP_ULL(NSEC_PER_SEC * (u64)val << (4 * prescale),
+ rzv2m_pwm->rate);
+ pm_runtime_put(chip->dev);
+
+ return 0;
+}
+
+static int rzv2m_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = to_rzv2m_pwm_chip(chip);
+ unsigned long pwm_cyc, pwm_low;
+ u8 prescale;
+ u32 pwm_ctr;
+ u64 pc, dc;
+ int err;
+
+ /*
+ * Refuse clk rates > 1 GHz to prevent overflowing the following
+ * calculation.
+ */
+ if (rzv2m_pwm->rate > NSEC_PER_SEC)
+ return -EINVAL;
+
+ /*
+ * Formula for calculating PWM Cycle Setting Register
+ * PWM cycle = (PWM period(ns) / (PWM_CLK period(ns) × Div ratio)) - 1
+ */
+
+ pc = mul_u64_u32_div(state->period, rzv2m_pwm->rate, NSEC_PER_SEC);
+ dc = mul_u64_u32_div(state->duty_cycle, rzv2m_pwm->rate, NSEC_PER_SEC);
+ prescale = rzv2m_pwm_calculate_prescale(rzv2m_pwm, pc);
+
+ pwm_cyc = pc >> (4 * prescale);
+ if (pwm_cyc)
+ pwm_cyc -= 1;
+
+ if (!FIELD_FIT(RZV2M_PWMCYC_PERIOD, pwm_cyc))
+ pwm_cyc = FIELD_MAX(RZV2M_PWMCYC_PERIOD);
+
+ pwm_low = dc >> (4 * prescale);
+ if (pwm_low)
+ pwm_low -= 1;
+
+ if (!FIELD_FIT(RZV2M_PWMCYC_PERIOD, pwm_low))
+ pwm_low = FIELD_MAX(RZV2M_PWMCYC_PERIOD);
+
+ /*
+ * A 100% duty cycle is only possible with PWMLOW > PWMCYC. if PWMCYC is
+ * 0xffffff a 100% duty cycle is not possible.
+ */
+ if (pwm_cyc == pwm_low && pwm_cyc == FIELD_MAX(RZV2M_PWMCYC_PERIOD))
+ pwm_cyc -= 1;
+
+ /*
+ * If the PWM channel is disabled, make sure to turn on the clock
+ * before writing the register.
+ */
+ if (!pwm->state.enabled) {
+ err = pm_runtime_resume_and_get(rzv2m_pwm->chip.dev);
+ if (err)
+ return err;
+ } else {
+ /*
+ * To change the setting value of the PWM cycle setting register
+ * (PWMm_PWMCYC), set the PWME bit of the PWM control register
+ * (PWMm_PWMCTR) to 0b and stop the counter operation.
+ */
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWME, 0);
+ rzv2m_pwm_wait_delay(rzv2m_pwm);
+ }
+
+ rzv2m_pwm_write(rzv2m_pwm, RZV2M_PWMCYC, pwm_cyc);
+ rzv2m_pwm_write(rzv2m_pwm, RZV2M_PWMLOW, pwm_low);
+
+ pwm_ctr = FIELD_PREP(RZV2M_PWMCTR_PWMPS, prescale);
+ if (state->polarity == PWM_POLARITY_NORMAL)
+ pwm_ctr |= RZV2M_PWMCTR_PWMHL;
+
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWMTM |
+ RZV2M_PWMCTR_PWMPS | RZV2M_PWMCTR_PWMHL, pwm_ctr);
+
+ if (pwm->state.enabled)
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWME,
+ RZV2M_PWMCTR_PWME);
+
+ rzv2m_pwm_wait_delay(rzv2m_pwm);
+
+ /* If the PWM is not enabled, turn the clock off again to save power. */
+ if (!pwm->state.enabled)
+ pm_runtime_put(rzv2m_pwm->chip.dev);
+
+ return 0;
+}
+
+static int rzv2m_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = to_rzv2m_pwm_chip(chip);
+ bool enabled = pwm->state.enabled;
+ int ret;
+
+ if (!state->enabled) {
+ if (enabled)
+ rzv2m_pwm_disable(rzv2m_pwm);
+
+ return 0;
+ }
+
+ ret = rzv2m_pwm_config(chip, pwm, state);
+ if (ret)
+ return ret;
+
+ if (!enabled)
+ ret = rzv2m_pwm_enable(rzv2m_pwm);
+
+ return ret;
+}
+
+static const struct pwm_ops rzv2m_pwm_ops = {
+ .get_state = rzv2m_pwm_get_state,
+ .apply = rzv2m_pwm_apply,
+ .owner = THIS_MODULE,
+};
+
+static int rzv2m_pwm_pm_runtime_suspend(struct device *dev)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(rzv2m_pwm->pwm_clk);
+ clk_disable_unprepare(rzv2m_pwm->apb_clk);
+
+ return 0;
+}
+
+static int rzv2m_pwm_pm_runtime_resume(struct device *dev)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = dev_get_drvdata(dev);
+
+ clk_prepare_enable(rzv2m_pwm->apb_clk);
+ clk_prepare_enable(rzv2m_pwm->pwm_clk);
+
+ return 0;
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(rzv2m_pwm_pm_ops,
+ rzv2m_pwm_pm_runtime_suspend,
+ rzv2m_pwm_pm_runtime_resume, NULL);
+
+static void rzv2m_pwm_reset_assert_pm_disable(void *data)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm = data;
+
+ /*
+ * The below check is for making balanced PM usage count in probe/remove
+ * eg: boot loader is turning on PWM and probe increments the PM usage
+ * count. Before apply, if there is unbind/remove callback we need to
+ * decrement the PM usage count.
+ */
+ clk_prepare_enable(rzv2m_pwm->apb_clk);
+ clk_prepare_enable(rzv2m_pwm->pwm_clk);
+
+ if (rzv2m_pwm_is_ch_enabled(rzv2m_pwm))
+ pm_runtime_put(rzv2m_pwm->chip.dev);
+
+ clk_disable_unprepare(rzv2m_pwm->pwm_clk);
+ clk_disable_unprepare(rzv2m_pwm->apb_clk);
+
+ pm_runtime_disable(rzv2m_pwm->chip.dev);
+ pm_runtime_set_suspended(rzv2m_pwm->chip.dev);
+ reset_control_assert(rzv2m_pwm->rstc);
+}
+
+static int rzv2m_pwm_probe(struct platform_device *pdev)
+{
+ struct rzv2m_pwm_chip *rzv2m_pwm;
+ unsigned long apb_clk_rate;
+ int ret;
+
+ rzv2m_pwm = devm_kzalloc(&pdev->dev, sizeof(*rzv2m_pwm), GFP_KERNEL);
+ if (!rzv2m_pwm)
+ return -ENOMEM;
+
+ rzv2m_pwm->mmio = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rzv2m_pwm->mmio))
+ return PTR_ERR(rzv2m_pwm->mmio);
+
+ rzv2m_pwm->apb_clk = devm_clk_get(&pdev->dev, "apb");
+ if (IS_ERR(rzv2m_pwm->apb_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(rzv2m_pwm->apb_clk),
+ "cannot get apb clock\n");
+
+ apb_clk_rate = clk_get_rate(rzv2m_pwm->apb_clk);
+ if (!apb_clk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "apb clk rate is 0");
+
+ rzv2m_pwm->pwm_clk = devm_clk_get(&pdev->dev, "pwm");
+ if (IS_ERR(rzv2m_pwm->pwm_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(rzv2m_pwm->pwm_clk),
+ "cannot get pwm clock\n");
+
+ rzv2m_pwm->rate = clk_get_rate(rzv2m_pwm->pwm_clk);
+ if (!rzv2m_pwm->rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "pwm clk rate is 0");
+
+ /* delay = 6 * PCLK + 9 * PWM_CLK */
+ rzv2m_pwm->delay = DIV_ROUND_UP(6 * 1000000000UL, apb_clk_rate) +
+ DIV_ROUND_UP(9 * 1000000000UL, rzv2m_pwm->rate);
+
+ rzv2m_pwm->rstc = devm_reset_control_get_shared(&pdev->dev, NULL);
+ if (IS_ERR(rzv2m_pwm->rstc))
+ return dev_err_probe(&pdev->dev, PTR_ERR(rzv2m_pwm->rstc),
+ "get reset failed\n");
+
+ platform_set_drvdata(pdev, rzv2m_pwm);
+ clk_prepare_enable(rzv2m_pwm->apb_clk);
+ clk_prepare_enable(rzv2m_pwm->pwm_clk);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ ret = reset_control_deassert(rzv2m_pwm->rstc);
+ if (ret) {
+ dev_err_probe(&pdev->dev, ret,
+ "cannot deassert reset control\n");
+ goto pm_clk_disable;
+ }
+
+ rzv2m_pwm->chip.dev = &pdev->dev;
+ /*
+ * We need to keep the clock on, in case the bootloader has enabled the
+ * PWM and is running during probe().
+ */
+ if (rzv2m_pwm_is_ch_enabled(rzv2m_pwm))
+ pm_runtime_get_sync(&pdev->dev);
+
+ ret = devm_add_action_or_reset(&pdev->dev,
+ rzv2m_pwm_reset_assert_pm_disable,
+ rzv2m_pwm);
+ if (ret < 0)
+ goto channel_disable;
+
+ rzv2m_pwm->chip.ops = &rzv2m_pwm_ops;
+ rzv2m_pwm->chip.npwm = 1;
+ ret = devm_pwmchip_add(&pdev->dev, &rzv2m_pwm->chip);
+ if (ret) {
+ dev_err_probe(&pdev->dev, ret, "failed to add PWM chip\n");
+ goto channel_disable;
+ }
+
+ return 0;
+
+pm_clk_disable:
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+channel_disable:
+ if (rzv2m_pwm_is_ch_enabled(rzv2m_pwm))
+ rzv2m_pwm_modify(rzv2m_pwm, RZV2M_PWMCTR, RZV2M_PWMCTR_PWME, 0);
+
+ clk_disable_unprepare(rzv2m_pwm->pwm_clk);
+ clk_disable_unprepare(rzv2m_pwm->apb_clk);
+ return ret;
+}
+
+static const struct of_device_id rzv2m_pwm_of_table[] = {
+ { .compatible = "renesas,rzv2m-pwm", },
+ { /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzv2m_pwm_of_table);
+
+static struct platform_driver rzv2m_pwm_driver = {
+ .driver = {
+ .name = "pwm-rzv2m",
+ .pm = pm_ptr(&rzv2m_pwm_pm_ops),
+ .of_match_table = of_match_ptr(rzv2m_pwm_of_table),
+ },
+ .probe = rzv2m_pwm_probe,
+};
+module_platform_driver(rzv2m_pwm_driver);
+
+MODULE_AUTHOR("Biju Das <biju.das.jz@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Renesas RZ/V2M PWM Timer Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pwm-rzv2m");
--
2.25.1
