--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/G2L General PWM Timer (GPT) driver
+ *
+ * Copyright (C) 2025 Renesas Electronics Corporation
+ *
+ * Hardware manual for this IP can be found here
+ * https://www.renesas.com/eu/en/document/mah/rzg2l-group-rzg2lc-group-users-manual-hardware-0?language=en
+ *
+ * Limitations:
+ * - Counter must be stopped before modifying Mode and Prescaler.
+ * - When PWM is disabled, the output is driven to inactive.
+ * - While the hardware supports both polarities, the driver (for now)
+ * only handles normal polarity.
+ * - General PWM Timer (GPT) has 8 HW channels for PWM operations and
+ * each HW channel have 2 IOs.
+ * - Each IO is modelled as an independent PWM channel.
+ * - When both channels are used, disabling the channel on one stops the
+ * other.
+ * - When both channels are used, the period of both IOs in the HW channel
+ * must be same (for now).
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/reset.h>
+#include <linux/time.h>
+#include <linux/units.h>
+
+#define RZG2L_GET_CH(hwpwm) ((hwpwm) / 2)
+#define RZG2L_GET_CH_OFFS(ch) (0x100 * (ch))
+
+#define RZG2L_GTCR(ch) (0x2c + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTUDDTYC(ch) (0x30 + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTIOR(ch) (0x34 + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTBER(ch) (0x40 + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTCNT(ch) (0x48 + RZG2L_GET_CH_OFFS(ch))
+#define RZG2L_GTCCR(ch, sub_ch) (0x4c + RZG2L_GET_CH_OFFS(ch) + 4 * (sub_ch))
+#define RZG2L_GTPR(ch) (0x64 + RZG2L_GET_CH_OFFS(ch))
+
+#define RZG2L_GTCR_CST BIT(0)
+#define RZG2L_GTCR_MD GENMASK(18, 16)
+#define RZG2L_GTCR_TPCS GENMASK(26, 24)
+
+#define RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE FIELD_PREP(RZG2L_GTCR_MD, 0)
+
+#define RZG2L_GTUDDTYC_UP BIT(0)
+#define RZG2L_GTUDDTYC_UDF BIT(1)
+#define RZG2L_GTUDDTYC_UP_COUNTING (RZG2L_GTUDDTYC_UP | RZG2L_GTUDDTYC_UDF)
+
+#define RZG2L_GTIOR_GTIOA GENMASK(4, 0)
+#define RZG2L_GTIOR_GTIOB GENMASK(20, 16)
+#define RZG2L_GTIOR_GTIOx(sub_ch) ((sub_ch) ? RZG2L_GTIOR_GTIOB : RZG2L_GTIOR_GTIOA)
+#define RZG2L_GTIOR_OAE BIT(8)
+#define RZG2L_GTIOR_OBE BIT(24)
+#define RZG2L_GTIOR_OxE(sub_ch) ((sub_ch) ? RZG2L_GTIOR_OBE : RZG2L_GTIOR_OAE)
+
+#define RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE 0x1b
+#define RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH \
+ (RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE | RZG2L_GTIOR_OAE)
+#define RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH \
+ (FIELD_PREP(RZG2L_GTIOR_GTIOB, RZG2L_INIT_OUT_HI_OUT_HI_END_TOGGLE) | RZG2L_GTIOR_OBE)
+
+#define RZG2L_GTIOR_GTIOx_OUT_HI_END_TOGGLE_CMP_MATCH(sub_ch) \
+ ((sub_ch) ? RZG2L_GTIOR_GTIOB_OUT_HI_END_TOGGLE_CMP_MATCH : \
+ RZG2L_GTIOR_GTIOA_OUT_HI_END_TOGGLE_CMP_MATCH)
+
+#define RZG2L_MAX_HW_CHANNELS 8
+#define RZG2L_CHANNELS_PER_IO 2
+#define RZG2L_MAX_PWM_CHANNELS (RZG2L_MAX_HW_CHANNELS * RZG2L_CHANNELS_PER_IO)
+#define RZG2L_MAX_SCALE_FACTOR 1024
+#define RZG2L_MAX_TICKS ((u64)U32_MAX * RZG2L_MAX_SCALE_FACTOR)
+
+struct rzg2l_gpt_chip {
+ void __iomem *mmio;
+ struct mutex lock; /* lock to protect shared channel resources */
+ unsigned long rate_khz;
+ u32 period_ticks[RZG2L_MAX_HW_CHANNELS];
+ u32 channel_request_count[RZG2L_MAX_HW_CHANNELS];
+ u32 channel_enable_count[RZG2L_MAX_HW_CHANNELS];
+};
+
+static inline struct rzg2l_gpt_chip *to_rzg2l_gpt_chip(struct pwm_chip *chip)
+{
+ return pwmchip_get_drvdata(chip);
+}
+
+static inline unsigned int rzg2l_gpt_subchannel(unsigned int hwpwm)
+{
+ return hwpwm & 0x1;
+}
+
+static void rzg2l_gpt_write(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg, u32 data)
+{
+ writel(data, rzg2l_gpt->mmio + reg);
+}
+
+static u32 rzg2l_gpt_read(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg)
+{
+ return readl(rzg2l_gpt->mmio + reg);
+}
+
+static void rzg2l_gpt_modify(struct rzg2l_gpt_chip *rzg2l_gpt, u32 reg, u32 clr,
+ u32 set)
+{
+ rzg2l_gpt_write(rzg2l_gpt, reg,
+ (rzg2l_gpt_read(rzg2l_gpt, reg) & ~clr) | set);
+}
+
+static u8 rzg2l_gpt_calculate_prescale(struct rzg2l_gpt_chip *rzg2l_gpt,
+ u64 period_ticks)
+{
+ u32 prescaled_period_ticks;
+ u8 prescale;
+
+ prescaled_period_ticks = period_ticks >> 32;
+ if (prescaled_period_ticks >= 256)
+ prescale = 5;
+ else
+ prescale = (fls(prescaled_period_ticks) + 1) / 2;
+
+ return prescale;
+}
+
+static int rzg2l_gpt_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+ u32 ch = RZG2L_GET_CH(pwm->hwpwm);
+
+ guard(mutex)(&rzg2l_gpt->lock);
+ rzg2l_gpt->channel_request_count[ch]++;
+
+ return 0;
+}
+
+static void rzg2l_gpt_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+ u32 ch = RZG2L_GET_CH(pwm->hwpwm);
+
+ guard(mutex)(&rzg2l_gpt->lock);
+ rzg2l_gpt->channel_request_count[ch]--;
+}
+
+static bool rzg2l_gpt_is_ch_enabled(struct rzg2l_gpt_chip *rzg2l_gpt, u8 hwpwm)
+{
+ u8 ch = RZG2L_GET_CH(hwpwm);
+ u32 val;
+
+ val = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCR(ch));
+ if (!(val & RZG2L_GTCR_CST))
+ return false;
+
+ val = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTIOR(ch));
+
+ return val & RZG2L_GTIOR_OxE(rzg2l_gpt_subchannel(hwpwm));
+}
+
+/* Caller holds the lock while calling rzg2l_gpt_enable() */
+static void rzg2l_gpt_enable(struct rzg2l_gpt_chip *rzg2l_gpt,
+ struct pwm_device *pwm)
+{
+ u8 sub_ch = rzg2l_gpt_subchannel(pwm->hwpwm);
+ u32 val = RZG2L_GTIOR_GTIOx(sub_ch) | RZG2L_GTIOR_OxE(sub_ch);
+ u8 ch = RZG2L_GET_CH(pwm->hwpwm);
+
+ /* Enable pin output */
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTIOR(ch), val,
+ RZG2L_GTIOR_GTIOx_OUT_HI_END_TOGGLE_CMP_MATCH(sub_ch));
+
+ if (!rzg2l_gpt->channel_enable_count[ch])
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), 0, RZG2L_GTCR_CST);
+
+ rzg2l_gpt->channel_enable_count[ch]++;
+}
+
+/* Caller holds the lock while calling rzg2l_gpt_disable() */
+static void rzg2l_gpt_disable(struct rzg2l_gpt_chip *rzg2l_gpt,
+ struct pwm_device *pwm)
+{
+ u8 sub_ch = rzg2l_gpt_subchannel(pwm->hwpwm);
+ u8 ch = RZG2L_GET_CH(pwm->hwpwm);
+
+ /* Stop count, Output low on GTIOCx pin when counting stops */
+ rzg2l_gpt->channel_enable_count[ch]--;
+
+ if (!rzg2l_gpt->channel_enable_count[ch])
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), RZG2L_GTCR_CST, 0);
+
+ /* Disable pin output */
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTIOR(ch), RZG2L_GTIOR_OxE(sub_ch), 0);
+}
+
+static u64 rzg2l_gpt_calculate_period_or_duty(struct rzg2l_gpt_chip *rzg2l_gpt,
+ u32 val, u8 prescale)
+{
+ u64 tmp;
+
+ /*
+ * The calculation doesn't overflow an u64 because prescale ≤ 5 and so
+ * tmp = val << (2 * prescale) * USEC_PER_SEC
+ * < 2^32 * 2^10 * 10^6
+ * < 2^32 * 2^10 * 2^20
+ * = 2^62
+ */
+ tmp = (u64)val << (2 * prescale);
+ tmp *= USEC_PER_SEC;
+
+ return DIV64_U64_ROUND_UP(tmp, rzg2l_gpt->rate_khz);
+}
+
+static int rzg2l_gpt_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+
+ state->enabled = rzg2l_gpt_is_ch_enabled(rzg2l_gpt, pwm->hwpwm);
+ if (state->enabled) {
+ u32 sub_ch = rzg2l_gpt_subchannel(pwm->hwpwm);
+ u32 ch = RZG2L_GET_CH(pwm->hwpwm);
+ u8 prescale;
+ u32 val;
+
+ val = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCR(ch));
+ prescale = FIELD_GET(RZG2L_GTCR_TPCS, val);
+
+ val = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTPR(ch));
+ state->period = rzg2l_gpt_calculate_period_or_duty(rzg2l_gpt, val, prescale);
+
+ val = rzg2l_gpt_read(rzg2l_gpt, RZG2L_GTCCR(ch, sub_ch));
+ state->duty_cycle = rzg2l_gpt_calculate_period_or_duty(rzg2l_gpt, val, prescale);
+ if (state->duty_cycle > state->period)
+ state->duty_cycle = state->period;
+ }
+
+ state->polarity = PWM_POLARITY_NORMAL;
+
+ return 0;
+}
+
+static u32 rzg2l_gpt_calculate_pv_or_dc(u64 period_or_duty_cycle, u8 prescale)
+{
+ return min_t(u64, DIV_ROUND_DOWN_ULL(period_or_duty_cycle, 1 << (2 * prescale)),
+ U32_MAX);
+}
+
+/* Caller holds the lock while calling rzg2l_gpt_config() */
+static int rzg2l_gpt_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+ u8 sub_ch = rzg2l_gpt_subchannel(pwm->hwpwm);
+ u8 ch = RZG2L_GET_CH(pwm->hwpwm);
+ u64 period_ticks, duty_ticks;
+ unsigned long pv, dc;
+ u8 prescale;
+
+ /* Limit period/duty cycle to max value supported by the HW */
+ period_ticks = mul_u64_u64_div_u64(state->period, rzg2l_gpt->rate_khz, USEC_PER_SEC);
+ if (period_ticks > RZG2L_MAX_TICKS)
+ period_ticks = RZG2L_MAX_TICKS;
+ /*
+ * GPT counter is shared by the two IOs of a single channel, so
+ * prescale and period can NOT be modified when there are multiple IOs
+ * in use with different settings.
+ */
+ if (rzg2l_gpt->channel_request_count[ch] > 1 && period_ticks != rzg2l_gpt->period_ticks[ch])
+ return -EBUSY;
+
+ prescale = rzg2l_gpt_calculate_prescale(rzg2l_gpt, period_ticks);
+ pv = rzg2l_gpt_calculate_pv_or_dc(period_ticks, prescale);
+
+ duty_ticks = mul_u64_u64_div_u64(state->duty_cycle, rzg2l_gpt->rate_khz, USEC_PER_SEC);
+ if (duty_ticks > RZG2L_MAX_TICKS)
+ duty_ticks = RZG2L_MAX_TICKS;
+ dc = rzg2l_gpt_calculate_pv_or_dc(duty_ticks, prescale);
+
+ /*
+ * GPT counter is shared by multiple channels, we cache the period ticks
+ * from the first enabled channel and use the same value for both
+ * channels.
+ */
+ rzg2l_gpt->period_ticks[ch] = period_ticks;
+
+ /*
+ * Counter must be stopped before modifying mode, prescaler, timer
+ * counter and buffer enable registers. These registers are shared
+ * between both channels. So allow updating these registers only for the
+ * first enabled channel.
+ */
+ if (rzg2l_gpt->channel_enable_count[ch] <= 1) {
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), RZG2L_GTCR_CST, 0);
+
+ /* GPT set operating mode (saw-wave up-counting) */
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), RZG2L_GTCR_MD,
+ RZG2L_GTCR_MD_SAW_WAVE_PWM_MODE);
+
+ /* Set count direction */
+ rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTUDDTYC(ch), RZG2L_GTUDDTYC_UP_COUNTING);
+
+ /* Select count clock */
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch), RZG2L_GTCR_TPCS,
+ FIELD_PREP(RZG2L_GTCR_TPCS, prescale));
+
+ /* Set period */
+ rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTPR(ch), pv);
+ }
+
+ /* Set duty cycle */
+ rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTCCR(ch, sub_ch), dc);
+
+ if (rzg2l_gpt->channel_enable_count[ch] <= 1) {
+ /* Set initial value for counter */
+ rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTCNT(ch), 0);
+
+ /* Set no buffer operation */
+ rzg2l_gpt_write(rzg2l_gpt, RZG2L_GTBER(ch), 0);
+
+ /* Restart the counter after updating the registers */
+ rzg2l_gpt_modify(rzg2l_gpt, RZG2L_GTCR(ch),
+ RZG2L_GTCR_CST, RZG2L_GTCR_CST);
+ }
+
+ return 0;
+}
+
+static int rzg2l_gpt_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+ bool enabled = pwm->state.enabled;
+ int ret;
+
+ if (state->polarity != PWM_POLARITY_NORMAL)
+ return -EINVAL;
+
+ guard(mutex)(&rzg2l_gpt->lock);
+ if (!state->enabled) {
+ if (enabled)
+ rzg2l_gpt_disable(rzg2l_gpt, pwm);
+
+ return 0;
+ }
+
+ ret = rzg2l_gpt_config(chip, pwm, state);
+ if (!ret && !enabled)
+ rzg2l_gpt_enable(rzg2l_gpt, pwm);
+
+ return ret;
+}
+
+static const struct pwm_ops rzg2l_gpt_ops = {
+ .request = rzg2l_gpt_request,
+ .free = rzg2l_gpt_free,
+ .get_state = rzg2l_gpt_get_state,
+ .apply = rzg2l_gpt_apply,
+};
+
+static int rzg2l_gpt_probe(struct platform_device *pdev)
+{
+ struct rzg2l_gpt_chip *rzg2l_gpt;
+ struct device *dev = &pdev->dev;
+ struct reset_control *rstc;
+ struct pwm_chip *chip;
+ unsigned long rate;
+ struct clk *clk;
+ int ret;
+
+ chip = devm_pwmchip_alloc(dev, RZG2L_MAX_PWM_CHANNELS, sizeof(*rzg2l_gpt));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+ rzg2l_gpt = to_rzg2l_gpt_chip(chip);
+
+ rzg2l_gpt->mmio = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rzg2l_gpt->mmio))
+ return PTR_ERR(rzg2l_gpt->mmio);
+
+ rstc = devm_reset_control_get_exclusive_deasserted(dev, NULL);
+ if (IS_ERR(rstc))
+ return dev_err_probe(dev, PTR_ERR(rstc), "Cannot deassert reset control\n");
+
+ clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "Cannot get clock\n");
+
+ ret = devm_clk_rate_exclusive_get(dev, clk);
+ if (ret)
+ return ret;
+
+ rate = clk_get_rate(clk);
+ if (!rate)
+ return dev_err_probe(dev, -EINVAL, "The gpt clk rate is 0");
+
+ /*
+ * Refuse clk rates > 1 GHz to prevent overflow later for computing
+ * period and duty cycle.
+ */
+ if (rate > NSEC_PER_SEC)
+ return dev_err_probe(dev, -EINVAL, "The gpt clk rate is > 1GHz");
+
+ /*
+ * Rate is in MHz and is always integer for peripheral clk
+ * 2^32 * 2^10 (prescalar) * 10^6 (rate_khz) < 2^64
+ * So make sure rate is multiple of 1000.
+ */
+ rzg2l_gpt->rate_khz = rate / KILO;
+ if (rzg2l_gpt->rate_khz * KILO != rate)
+ return dev_err_probe(dev, -EINVAL, "Rate is not multiple of 1000");
+
+ mutex_init(&rzg2l_gpt->lock);
+
+ chip->ops = &rzg2l_gpt_ops;
+ ret = devm_pwmchip_add(dev, chip);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
+
+ return 0;
+}
+
+static const struct of_device_id rzg2l_gpt_of_table[] = {
+ { .compatible = "renesas,rzg2l-gpt", },
+ { /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzg2l_gpt_of_table);
+
+static struct platform_driver rzg2l_gpt_driver = {
+ .driver = {
+ .name = "pwm-rzg2l-gpt",
+ .of_match_table = rzg2l_gpt_of_table,
+ },
+ .probe = rzg2l_gpt_probe,
+};
+module_platform_driver(rzg2l_gpt_driver);
+
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
+MODULE_DESCRIPTION("Renesas RZ/G2L General PWM Timer (GPT) Driver");
+MODULE_LICENSE("GPL");
projects / users / willy / linux.git / commitdiff