* [PATCH v16 2/2] pwm: airoha: Add support for EN7581 SoC
2025-06-25 0:00 [PATCH v16 1/2] math64.h: provide rounddown_u64 variant for rounddown macro Christian Marangi
@ 2025-06-25 0:00 ` Christian Marangi
2025-06-25 7:24 ` Uwe Kleine-König
2025-06-25 11:39 ` [PATCH v16 1/2] math64.h: provide rounddown_u64 variant for rounddown macro Andy Shevchenko
1 sibling, 1 reply; 9+ messages in thread
From: Christian Marangi @ 2025-06-25 0:00 UTC (permalink / raw)
To: Uwe Kleine-König, Christian Marangi, linux-kernel, linux-pwm,
Andy Shevchenko
Cc: Benjamin Larsson, AngeloGioacchino Del Regno, Lorenzo Bianconi
From: Benjamin Larsson <benjamin.larsson@genexis.eu>
Introduce driver for PWM module available on EN7581 SoC.
Signed-off-by: Benjamin Larsson <benjamin.larsson@genexis.eu>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Co-developed-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
Changes v16:
- Always check regmap return
- Add missing header
- Use bitmask APIs
- Use refcount instead of raw u64
- Fix spelling mistake and improve text
- Drop OF dependency
- Drop redundant always true if condition
- Add myself as Author
Changes v15:
- Fix compilation error for 64bit division on 32bit (patch 01)
- Add prefer async probe
Changes v14:
- Fix logic for bucket recycle
(was tested by not releasing the bucket and observing
the best one gets used)
- Assign bucket period and duty only if not used
- Skip bucket period/duty calculation if already used
- Permit disable also if inversed polarity is asked
- Normalize duty similar to period
Changes v13:
- Reorder include
- Split ticks_from_ns function
- Add additional comments for shift register chip clock
- Address suggested minor optimization (Uwe)
Changes v12:
- Make shift function more readable
- Use unsigned int where possible
- Better comment some SIPO strangeness
- Move SIPO init after flash map config
- Retrun real values in get_state instead of the
one saved in bucket
- Improve period_ns parsing so we can better share generators
Changes v11:
- Fix wrong calculation of period and duty
- Use AIROHA_PWM prefix for each define
- Drop set/get special define in favour of BITS and GENMASK
- Correctly use dev_err_probe
- Init bucket with initial values
- Rework define to make use of FIELD_PREP and FIELD_GET
Changes in v10:
- repost just patch 6/6 (pwm driver) since patches {1/6-5/6} have been
already applied in linux-pinctrl tree
- pwm: introduce AIROHA_PWM_FIELD_GET and AIROHA_PWM_FIELD_SET macros to
get/set field with non-const mask
- pwm: simplify airoha_pwm_get_generator() to report unused generator
and remove double lookup
- pwm: remove device_node pointer in airoha_pwm struct since this is
write-only field
- pwm: cosmetics
- Link to v9: https://lore.kernel.org/r/20241023-en7581-pinctrl-v9-0-afb0cbcab0ec@kernel.org
Changes in v9:
- pwm: remove unused properties
- Link to v8: https://lore.kernel.org/r/20241018-en7581-pinctrl-v8-0-b676b966a1d1@kernel.org
Changes in v8:
- pwm: add missing properties documentation
- Link to v7: https://lore.kernel.org/r/20241016-en7581-pinctrl-v7-0-4ff611f263a7@kernel.org
Changes in v7:
- pinctrl: cosmetics
- pinctrl: fix compilation warning
- Link to v6: https://lore.kernel.org/r/20241013-en7581-pinctrl-v6-0-2048e2d099c2@kernel.org
Changes in v6:
- pwm: rely on regmap APIs
- pwm: introduce compatible string
- pinctrl: introduce compatible string
- remove airoha-mfd driver
- add airoha,en7581-pinctrl binding
- add airoha,en7581-pwm binding
- update airoha,en7581-gpio-sysctl binding
- Link to v5: https://lore.kernel.org/r/20241001-en7581-pinctrl-v5-0-dc1ce542b6c6@kernel.org
Changes in v5:
- use spin_lock in airoha_pinctrl_rmw instead of a mutex since it can run
in interrupt context
- remove unused includes in pinctrl driver
- since the irq_chip is immutable, allocate the gpio_irq_chip struct
statically in pinctrl driver
- rely on regmap APIs in pinctrl driver but keep the spin_lock local to the
driver
- rely on guard/guard_scope APIs in pinctrl driver
- improve naming convention pinctrl driver
- introduce airoha_pinconf_set_pin_value utility routine
- Link to v4: https://lore.kernel.org/r/20240911-en7581-pinctrl-v4-0-60ac93d760bb@kernel.org
Changes in v4:
- add 'Limitation' description in pwm driver
- fix comments in pwm driver
- rely on mfd->base __iomem pointer in pwm driver, modify register
offsets according to it and get rid of sgpio_cfg, flash_cfg and
cycle_cfg pointers
- simplify register utility routines in pwm driver
- use 'generator' instead of 'waveform' suffix for pwm routines
- fix possible overflow calculating duty cycle in pwm driver
- do not modify pwm state in free callback in pwm driver
- cap the maximum period in pwm driver
- do not allow inverse polarity in pwm driver
- do not set of_xlate callback in the pwm driver and allow the stack to
do it
- fix MAINTAINERS file for airoha pinctrl driver
- fix undefined reference to __ffsdi2 in pinctrl driver
- simplify airoha,en7581-gpio-sysctl.yam binding
- Link to v3: https://lore.kernel.org/r/20240831-en7581-pinctrl-v3-0-98eebfb4da66@kernel.org
Changes in v3:
- introduce airoha-mfd driver
- add pwm driver to the same series
- model pinctrl and pwm drivers as childs of a parent mfd driver.
- access chip-scu memory region in pinctrl driver via syscon
- introduce a single airoha,en7581-gpio-sysctl.yaml binding and get rid
of dedicated bindings for pinctrl and pwm
- add airoha,en7581-chip-scu.yaml binding do the series
- Link to v2: https://lore.kernel.org/r/20240822-en7581-pinctrl-v2-0-ba1559173a7f@kernel.org
Changes in v2:
- Fix compilation errors
- Collapse some register mappings for gpio and irq controllers
- update dt-bindings according to new register mapping
- fix some dt-bindings errors
- Link to v1: https://lore.kernel.org/all/cover.1723392444.git.lorenzo@kernel.org/
drivers/pwm/Kconfig | 10 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-airoha.c | 613 +++++++++++++++++++++++++++++++++++++++
3 files changed, 624 insertions(+)
create mode 100644 drivers/pwm/pwm-airoha.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c866ed388da9..4aa7d94cd680 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -54,6 +54,16 @@ config PWM_ADP5585
This option enables support for the PWM function found in the Analog
Devices ADP5585.
+config PWM_AIROHA
+ tristate "Airoha PWM support"
+ depends on ARCH_AIROHA || COMPILE_TEST
+ select REGMAP_MMIO
+ help
+ Generic PWM framework driver for Airoha SoC.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-airoha.
+
config PWM_APPLE
tristate "Apple SoC PWM support"
depends on ARCH_APPLE || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 5c782af8f49b..cd3e6de2e44a 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -2,6 +2,7 @@
obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
obj-$(CONFIG_PWM_ADP5585) += pwm-adp5585.o
+obj-$(CONFIG_PWM_AIROHA) += pwm-airoha.o
obj-$(CONFIG_PWM_APPLE) += pwm-apple.o
obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
diff --git a/drivers/pwm/pwm-airoha.c b/drivers/pwm/pwm-airoha.c
new file mode 100644
index 000000000000..836c9c73f779
--- /dev/null
+++ b/drivers/pwm/pwm-airoha.c
@@ -0,0 +1,613 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2022 Markus Gothe <markus.gothe@genexis.eu>
+ *
+ * Limitations:
+ * - Only 8 concurrent waveform generators are available for 8 combinations of
+ * duty_cycle and period. Waveform generators are shared between 16 GPIO
+ * pins and 17 SIPO GPIO pins.
+ * - Supports only normal polarity.
+ * - On configuration the currently running period is completed.
+ * - Minimum supported period is 4ms
+ * - Maximum supported period is 1s
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/math64.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/refcount.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+#define AIROHA_PWM_REG_SGPIO_LED_DATA 0x0024
+#define AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG BIT(31)
+#define AIROHA_PWM_SGPIO_LED_DATA_DATA GENMASK(16, 0)
+
+#define AIROHA_PWM_REG_SGPIO_CLK_DIVR 0x0028
+#define AIROHA_PWM_SGPIO_CLK_DIVR GENMASK(1, 0)
+#define AIROHA_PWM_SGPIO_CLK_DIVR_32 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 0x3)
+#define AIROHA_PWM_SGPIO_CLK_DIVR_16 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 0x2)
+#define AIROHA_PWM_SGPIO_CLK_DIVR_8 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 0x1)
+#define AIROHA_PWM_SGPIO_CLK_DIVR_4 FIELD_PREP_CONST(AIROHA_PWM_SGPIO_CLK_DIVR, 0x0)
+
+#define AIROHA_PWM_REG_SGPIO_CLK_DLY 0x002c
+
+#define AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG 0x0030
+#define AIROHA_PWM_SERIAL_GPIO_FLASH_MODE BIT(1)
+#define AIROHA_PWM_SERIAL_GPIO_MODE_74HC164 BIT(0)
+
+#define AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(_n) (0x003c + (4 * (_n)))
+#define AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(_n) (16 * (_n))
+#define AIROHA_PWM_GPIO_FLASH_PRD_LOW GENMASK(15, 8)
+#define AIROHA_PWM_GPIO_FLASH_PRD_HIGH GENMASK(7, 0)
+
+#define AIROHA_PWM_REG_GPIO_FLASH_MAP(_n) (0x004c + (4 * (_n)))
+#define AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(_n) (4 * (_n))
+#define AIROHA_PWM_GPIO_FLASH_EN BIT(3)
+#define AIROHA_PWM_GPIO_FLASH_SET_ID GENMASK(2, 0)
+
+/* Register map is equal to GPIO flash map */
+#define AIROHA_PWM_REG_SIPO_FLASH_MAP(_n) (0x0054 + (4 * (_n)))
+
+#define AIROHA_PWM_REG_CYCLE_CFG_VALUE(_n) (0x0098 + (4 * (_n)))
+#define AIROHA_PWM_REG_CYCLE_CFG_SHIFT(_n) (8 * (_n))
+#define AIROHA_PWM_WAVE_GEN_CYCLE GENMASK(7, 0)
+
+/* GPIO/SIPO flash map handles 8 pins in one register */
+#define AIROHA_PWM_PINS_PER_FLASH_MAP 8
+/* Cycle cfg handles 4 generators in one register */
+#define AIROHA_PWM_BUCKET_PER_CYCLE_CFG 4
+/* Flash producer handles 2 generators in one register */
+#define AIROHA_PWM_BUCKET_PER_FLASH_PROD 2
+
+#define AIROHA_PWM_NUM_BUCKETS 8
+/*
+ * The first 16 GPIO pins, GPIO0-GPIO15, are mapped into 16 PWM channels, 0-15.
+ * The SIPO GPIO pins are 17 pins which are mapped into 17 PWM channels, 16-32.
+ * However, we've only got 8 concurrent waveform generators and can therefore
+ * only use up to 8 different combinations of duty cycle and period at a time.
+ */
+#define AIROHA_PWM_NUM_GPIO 16
+#define AIROHA_PWM_NUM_SIPO 17
+#define AIROHA_PWM_MAX_CHANNELS (AIROHA_PWM_NUM_GPIO + AIROHA_PWM_NUM_SIPO)
+
+struct airoha_pwm_bucket {
+ /* Track concurrent usage of the bucket */
+ refcount_t used;
+ u64 period_ns;
+ u64 duty_ns;
+};
+
+struct airoha_pwm {
+ struct regmap *regmap;
+
+ DECLARE_BITMAP(initialized, AIROHA_PWM_MAX_CHANNELS);
+
+ struct airoha_pwm_bucket buckets[AIROHA_PWM_NUM_BUCKETS];
+
+ /* Cache bucket used by each pwm channel */
+ u8 channel_bucket[AIROHA_PWM_MAX_CHANNELS];
+};
+
+/* The PWM hardware supports periods between 4 ms and 1 s */
+#define AIROHA_PWM_PERIOD_TICK_NS (4 * NSEC_PER_MSEC)
+#define AIROHA_PWM_PERIOD_MAX_NS (1 * NSEC_PER_SEC)
+/* It is represented internally as 1/250 s between 1 and 250. Unit is ticks. */
+#define AIROHA_PWM_PERIOD_MIN 1
+#define AIROHA_PWM_PERIOD_MAX 250
+/* Duty cycle is relative with 255 corresponding to 100% */
+#define AIROHA_PWM_DUTY_FULL 255
+
+static void airoha_pwm_get_flash_map_addr_and_shift(unsigned int hwpwm,
+ u32 *addr, u32 *shift)
+{
+ unsigned int offset, hwpwm_bit;
+
+ if (hwpwm >= AIROHA_PWM_NUM_GPIO) {
+ unsigned int sipohwpwm = hwpwm - AIROHA_PWM_NUM_GPIO;
+
+ offset = sipohwpwm / AIROHA_PWM_PINS_PER_FLASH_MAP;
+ hwpwm_bit = sipohwpwm % AIROHA_PWM_PINS_PER_FLASH_MAP;
+
+ /* One FLASH_MAP register handles 8 pins */
+ *shift = AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(hwpwm_bit);
+ *addr = AIROHA_PWM_REG_SIPO_FLASH_MAP(offset);
+ } else {
+ offset = hwpwm / AIROHA_PWM_PINS_PER_FLASH_MAP;
+ hwpwm_bit = hwpwm % AIROHA_PWM_PINS_PER_FLASH_MAP;
+
+ /* One FLASH_MAP register handles 8 pins */
+ *shift = AIROHA_PWM_REG_GPIO_FLASH_MAP_SHIFT(hwpwm_bit);
+ *addr = AIROHA_PWM_REG_GPIO_FLASH_MAP(offset);
+ }
+}
+
+static u32 airoha_pwm_get_period_ticks_from_ns(u64 period_ns)
+{
+ return div_u64(period_ns, AIROHA_PWM_PERIOD_TICK_NS);
+}
+
+static u32 airoha_pwm_get_duty_ticks_from_ns(u64 period_ns, u64 duty_ns)
+{
+ return mul_u64_u64_div_u64(duty_ns, AIROHA_PWM_DUTY_FULL,
+ period_ns);
+}
+
+static int airoha_pwm_get_bucket(struct airoha_pwm *pc, int bucket,
+ u64 *period_ns, u64 *duty_ns)
+{
+ u32 period_tick, duty_tick;
+ unsigned int offset;
+ u32 shift, val;
+ int ret;
+
+ offset = bucket / AIROHA_PWM_BUCKET_PER_CYCLE_CFG;
+ shift = bucket % AIROHA_PWM_BUCKET_PER_CYCLE_CFG;
+ shift = AIROHA_PWM_REG_CYCLE_CFG_SHIFT(shift);
+
+ ret = regmap_read(pc->regmap, AIROHA_PWM_REG_CYCLE_CFG_VALUE(offset),
+ &val);
+ if (ret)
+ return ret;
+
+ period_tick = FIELD_GET(AIROHA_PWM_WAVE_GEN_CYCLE, val >> shift);
+ *period_ns = period_tick * AIROHA_PWM_PERIOD_TICK_NS;
+
+ offset = bucket / AIROHA_PWM_BUCKET_PER_FLASH_PROD;
+ shift = bucket % AIROHA_PWM_BUCKET_PER_FLASH_PROD;
+ shift = AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(shift);
+
+ ret = regmap_read(pc->regmap, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset),
+ &val);
+ if (ret)
+ return ret;
+
+ duty_tick = FIELD_GET(AIROHA_PWM_GPIO_FLASH_PRD_HIGH, val >> shift);
+ /*
+ * Overflow can't occur in multiplication as duty_tick is just 8 bit
+ * and period_ns is clamped to AIROHA_PWM_PERIOD_MAX_NS and fit in a
+ * u64.
+ */
+ *duty_ns = DIV_U64_ROUND_UP(duty_tick * *period_ns, AIROHA_PWM_DUTY_FULL);
+
+ return 0;
+}
+
+static int airoha_pwm_get_generator(struct airoha_pwm *pc, u64 duty_ns,
+ u64 period_ns)
+{
+ int best = -ENOENT, unused = -ENOENT;
+ u64 best_period_ns = 0;
+ u64 best_duty_ns = 0;
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(pc->buckets); i++) {
+ struct airoha_pwm_bucket *bucket = &pc->buckets[i];
+ u64 bucket_period_ns = bucket->period_ns;
+ u64 bucket_duty_ns = bucket->duty_ns;
+ u32 duty_ticks, duty_ticks_bucket;
+
+ /* If found, save an unused bucket to return it later */
+ if (refcount_read(&bucket->used) == 0) {
+ unused = i;
+ continue;
+ }
+
+ /* We found a matching bucket, exit early */
+ if (duty_ns == bucket_duty_ns &&
+ period_ns == bucket_period_ns)
+ return i;
+
+ /*
+ * Unlike duty cycle zero, which can be handled by
+ * disabling PWM, a generator is needed for full duty
+ * cycle but it can be reused regardless of period
+ */
+ duty_ticks = airoha_pwm_get_duty_ticks_from_ns(period_ns, duty_ns);
+ duty_ticks_bucket = airoha_pwm_get_duty_ticks_from_ns(bucket_period_ns,
+ bucket_duty_ns);
+ if (duty_ticks == AIROHA_PWM_DUTY_FULL &&
+ duty_ticks_bucket == AIROHA_PWM_DUTY_FULL)
+ return i;
+
+ /*
+ * With an unused bucket available, skip searching for
+ * a bucket to recycle (closer to the requested period/duty)
+ */
+ if (unused != -ENOENT)
+ continue;
+
+ /* Ignore bucket with invalid configs */
+ if (bucket_period_ns > period_ns ||
+ bucket_duty_ns > duty_ns)
+ continue;
+
+ /*
+ * Search for a bucket closer to the requested period/duty
+ * that has the maximal possible period that isn't bigger
+ * than the requested period. For that period pick the maximal
+ * duty_cycle that isn't bigger than the requested duty_cycle.
+ */
+ if (bucket_period_ns > best_period_ns ||
+ (bucket_period_ns == best_period_ns &&
+ bucket_duty_ns > best_duty_ns)) {
+ best_period_ns = bucket_period_ns;
+ best_duty_ns = bucket_duty_ns;
+ best = i;
+ }
+ }
+
+ /* With no unused bucket, return the best one found (if ever) */
+ return unused == -ENOENT ? best : unused;
+}
+
+static void airoha_pwm_release_bucket_config(struct airoha_pwm *pc,
+ unsigned int hwpwm)
+{
+ int bucket;
+
+ /* Nothing to clear, PWM channel never used */
+ if (!test_bit(hwpwm, pc->initialized))
+ return;
+
+ bucket = pc->channel_bucket[hwpwm];
+ refcount_dec(&pc->buckets[bucket].used);
+}
+
+static int airoha_pwm_apply_bucket_config(struct airoha_pwm *pc, int bucket,
+ u64 duty_ns, u64 period_ns)
+{
+ u32 period_ticks, duty_ticks;
+ u32 mask, shift, val;
+ u64 offset;
+ int ret;
+
+ period_ticks = airoha_pwm_get_period_ticks_from_ns(period_ns);
+ duty_ticks = airoha_pwm_get_duty_ticks_from_ns(period_ns, duty_ns);
+
+ offset = bucket;
+ shift = do_div(offset, AIROHA_PWM_BUCKET_PER_CYCLE_CFG);
+ shift = AIROHA_PWM_REG_CYCLE_CFG_SHIFT(shift);
+
+ /* Configure frequency divisor */
+ mask = AIROHA_PWM_WAVE_GEN_CYCLE << shift;
+ val = FIELD_PREP(AIROHA_PWM_WAVE_GEN_CYCLE, period_ticks) << shift;
+ ret = regmap_update_bits(pc->regmap, AIROHA_PWM_REG_CYCLE_CFG_VALUE(offset),
+ mask, val);
+ if (ret)
+ return ret;
+
+ offset = bucket;
+ shift = do_div(offset, AIROHA_PWM_BUCKET_PER_FLASH_PROD);
+ shift = AIROHA_PWM_REG_GPIO_FLASH_PRD_SHIFT(shift);
+
+ /* Configure duty cycle */
+ mask = AIROHA_PWM_GPIO_FLASH_PRD_HIGH << shift;
+ val = FIELD_PREP(AIROHA_PWM_GPIO_FLASH_PRD_HIGH, duty_ticks) << shift;
+ ret = regmap_update_bits(pc->regmap, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset),
+ mask, val);
+ if (ret)
+ return ret;
+
+ mask = AIROHA_PWM_GPIO_FLASH_PRD_LOW << shift;
+ val = FIELD_PREP(AIROHA_PWM_GPIO_FLASH_PRD_LOW,
+ AIROHA_PWM_DUTY_FULL - duty_ticks) << shift;
+ return regmap_update_bits(pc->regmap, AIROHA_PWM_REG_GPIO_FLASH_PRD_SET(offset),
+ mask, val);
+}
+
+static int airoha_pwm_consume_generator(struct airoha_pwm *pc,
+ u64 duty_ns, u64 period_ns,
+ unsigned int hwpwm)
+{
+ int bucket, ret;
+
+ /*
+ * Search for a bucket that already satisfies duty and period
+ * or an unused one.
+ * If not found, -ENOENT is returned.
+ */
+ bucket = airoha_pwm_get_generator(pc, duty_ns, period_ns);
+ if (bucket < 0)
+ return bucket;
+
+ /* Release previous used bucket (if any) */
+ airoha_pwm_release_bucket_config(pc, hwpwm);
+ if (refcount_read(&pc->buckets[bucket].used) == 0) {
+ pc->buckets[bucket].period_ns = period_ns;
+ pc->buckets[bucket].duty_ns = duty_ns;
+ ret = airoha_pwm_apply_bucket_config(pc, bucket,
+ duty_ns,
+ period_ns);
+ if (ret)
+ return ret;
+
+ refcount_set(&pc->buckets[bucket].used, 1);
+ } else {
+ refcount_inc(&pc->buckets[bucket].used);
+ }
+
+ return bucket;
+}
+
+static int airoha_pwm_sipo_init(struct airoha_pwm *pc)
+{
+ u32 val;
+ int ret;
+
+ ret = regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG,
+ AIROHA_PWM_SERIAL_GPIO_MODE_74HC164);
+ if (ret)
+ return ret;
+
+ /* Configure shift register chip clock timings, use 32x divisor */
+ ret = regmap_write(pc->regmap, AIROHA_PWM_REG_SGPIO_CLK_DIVR,
+ AIROHA_PWM_SGPIO_CLK_DIVR_32);
+ if (ret)
+ return ret;
+
+ /*
+ * Configure the shift register chip clock delay. This needs
+ * to be configured based on the chip characteristics when the SoC
+ * apply the shift register configuration.
+ * This doesn't affect actual PWM operation and is only specific to
+ * the shift register chip.
+ *
+ * For 74HC164 we set it to 0.
+ *
+ * For reference, the actual delay applied is the internal clock
+ * feed to the SGPIO chip + 1.
+ *
+ * From documentation is specified that clock delay should not be
+ * greater than (AIROHA_PWM_REG_SGPIO_CLK_DIVR / 2) - 1.
+ */
+ ret = regmap_write(pc->regmap, AIROHA_PWM_REG_SGPIO_CLK_DLY, 0);
+ if (ret)
+ return ret;
+
+ /*
+ * It is necessary to explicitly shift out all zeros after muxing
+ * to initialize the shift register before enabling PWM
+ * mode because in PWM mode SIPO will not start shifting until
+ * it needs to output a non-zero value (bit 31 of led_data
+ * indicates shifting in progress and it must return to zero
+ * before led_data can be written or PWM mode can be set)
+ */
+ ret = regmap_read_poll_timeout(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA, val,
+ !(val & AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG),
+ 10, 200 * USEC_PER_MSEC);
+ if (ret)
+ return ret;
+
+ ret = regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA,
+ AIROHA_PWM_SGPIO_LED_DATA_DATA);
+ if (ret)
+ return ret;
+ ret = regmap_read_poll_timeout(pc->regmap, AIROHA_PWM_REG_SGPIO_LED_DATA, val,
+ !(val & AIROHA_PWM_SGPIO_LED_DATA_SHIFT_FLAG),
+ 10, 200 * USEC_PER_MSEC);
+ if (ret)
+ return ret;
+
+ /* Set SIPO in PWM mode */
+ return regmap_set_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG,
+ AIROHA_PWM_SERIAL_GPIO_FLASH_MODE);
+}
+
+static int airoha_pwm_config_flash_map(struct airoha_pwm *pc,
+ unsigned int hwpwm, int index)
+{
+ unsigned int addr;
+ u32 shift;
+ int ret;
+
+ airoha_pwm_get_flash_map_addr_and_shift(hwpwm, &addr, &shift);
+
+ /* negative index means disable PWM channel */
+ if (index < 0) {
+ /*
+ * If we need to disable the PWM, we just put low the
+ * GPIO. No need to setup buckets.
+ */
+ return regmap_clear_bits(pc->regmap, addr,
+ AIROHA_PWM_GPIO_FLASH_EN << shift);
+ }
+
+ ret = regmap_update_bits(pc->regmap, addr,
+ AIROHA_PWM_GPIO_FLASH_SET_ID << shift,
+ FIELD_PREP(AIROHA_PWM_GPIO_FLASH_SET_ID, index) << shift);
+ if (ret)
+ return ret;
+
+ return regmap_set_bits(pc->regmap, addr, AIROHA_PWM_GPIO_FLASH_EN << shift);
+}
+
+static int airoha_pwm_config(struct airoha_pwm *pc, struct pwm_device *pwm,
+ u64 duty_ns, u64 period_ns)
+{
+ unsigned int hwpwm = pwm->hwpwm;
+ int bucket, ret;
+
+ bucket = airoha_pwm_consume_generator(pc, duty_ns, period_ns,
+ hwpwm);
+ if (bucket < 0)
+ return bucket;
+
+ ret = airoha_pwm_config_flash_map(pc, hwpwm, bucket);
+ if (ret) {
+ refcount_dec(&pc->buckets[bucket].used);
+ return ret;
+ }
+
+ set_bit(hwpwm, pc->initialized);
+ pc->channel_bucket[hwpwm] = bucket;
+
+ /*
+ * SIPO are special GPIO attached to a shift register chip. The handling
+ * of this chip is internal to the SoC that takes care of applying the
+ * values based on the flash map. To apply a new flash map, it's needed
+ * to trigger a refresh on the shift register chip.
+ * If a SIPO is getting configuring , always reinit the shift register
+ * chip to make sure the correct flash map is applied.
+ * Skip reconfiguring the shift register if the related hwpwm
+ * is disabled (as it doesn't need to be mapped).
+ */
+ if (hwpwm >= AIROHA_PWM_NUM_GPIO) {
+ ret = airoha_pwm_sipo_init(pc);
+ if (ret) {
+ airoha_pwm_release_bucket_config(pc, hwpwm);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+static void airoha_pwm_disable(struct airoha_pwm *pc, struct pwm_device *pwm)
+{
+ /* Disable PWM and release the bucket */
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, -1);
+ airoha_pwm_release_bucket_config(pc, pwm->hwpwm);
+
+ clear_bit(pwm->hwpwm, pc->initialized);
+
+ /* If no SIPO is used, disable the shift register chip */
+ if (find_next_bit(pc->initialized, AIROHA_PWM_MAX_CHANNELS,
+ AIROHA_PWM_NUM_GPIO) >= AIROHA_PWM_NUM_GPIO)
+ regmap_clear_bits(pc->regmap, AIROHA_PWM_REG_SIPO_FLASH_MODE_CFG,
+ AIROHA_PWM_SERIAL_GPIO_FLASH_MODE);
+}
+
+static int airoha_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct airoha_pwm *pc = pwmchip_get_drvdata(chip);
+ u64 duty_ns = state->duty_cycle;
+ u64 period_ns = state->period;
+
+ if (!state->enabled) {
+ airoha_pwm_disable(pc, pwm);
+ return 0;
+ }
+
+ /* Only normal polarity is supported */
+ if (state->polarity == PWM_POLARITY_INVERSED)
+ return -EINVAL;
+
+ /* Exit early if period is less than minimum supported */
+ if (period_ns < AIROHA_PWM_PERIOD_TICK_NS)
+ return -EINVAL;
+
+ /*
+ * Period goes at 4ns step, normalize it to check if we can
+ * share a generator.
+ */
+ period_ns = rounddown_u64(period_ns, AIROHA_PWM_PERIOD_TICK_NS);
+
+ /*
+ * Duty is divided in 255 segment, normalize it to check if we
+ * can share a generator.
+ */
+ duty_ns = DIV_U64_ROUND_UP(duty_ns * AIROHA_PWM_DUTY_FULL,
+ AIROHA_PWM_DUTY_FULL);
+
+ /* Clamp period to MAX supported value */
+ if (period_ns > AIROHA_PWM_PERIOD_MAX_NS) {
+ period_ns = AIROHA_PWM_PERIOD_MAX_NS;
+
+ if (duty_ns > period_ns)
+ duty_ns = period_ns;
+ }
+
+ return airoha_pwm_config(pc, pwm, duty_ns, period_ns);
+}
+
+static int airoha_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct airoha_pwm *pc = pwmchip_get_drvdata(chip);
+ int ret, hwpwm = pwm->hwpwm;
+ u32 addr, shift, val;
+ u8 bucket;
+
+ airoha_pwm_get_flash_map_addr_and_shift(hwpwm, &addr, &shift);
+
+ ret = regmap_read(pc->regmap, addr, &val);
+ if (ret)
+ return ret;
+
+ state->enabled = FIELD_GET(AIROHA_PWM_GPIO_FLASH_EN, val >> shift);
+ if (!state->enabled)
+ return 0;
+
+ state->polarity = PWM_POLARITY_NORMAL;
+
+ bucket = FIELD_GET(AIROHA_PWM_GPIO_FLASH_SET_ID, val >> shift);
+ return airoha_pwm_get_bucket(pc, bucket, &state->period,
+ &state->duty_cycle);
+}
+
+static const struct pwm_ops airoha_pwm_ops = {
+ .apply = airoha_pwm_apply,
+ .get_state = airoha_pwm_get_state,
+};
+
+static int airoha_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct airoha_pwm *pc;
+ struct pwm_chip *chip;
+ unsigned int i;
+ int ret;
+
+ chip = devm_pwmchip_alloc(dev, AIROHA_PWM_MAX_CHANNELS, sizeof(*pc));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+
+ chip->ops = &airoha_pwm_ops;
+ pc = pwmchip_get_drvdata(chip);
+
+ pc->regmap = device_node_to_regmap(dev->parent->of_node);
+ if (IS_ERR(pc->regmap))
+ return dev_err_probe(dev, PTR_ERR(pc->regmap), "Failed to get PWM regmap\n");
+
+ for (i = 0; i < ARRAY_SIZE(pc->buckets); i++)
+ refcount_set(&pc->buckets[i].used, 0);
+
+ ret = devm_pwmchip_add(&pdev->dev, chip);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
+
+ return 0;
+}
+
+static const struct of_device_id airoha_pwm_of_match[] = {
+ { .compatible = "airoha,en7581-pwm" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, airoha_pwm_of_match);
+
+static struct platform_driver airoha_pwm_driver = {
+ .driver = {
+ .name = "pwm-airoha",
+ .probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ .of_match_table = airoha_pwm_of_match,
+ },
+ .probe = airoha_pwm_probe,
+};
+module_platform_driver(airoha_pwm_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo@kernel.org>");
+MODULE_AUTHOR("Markus Gothe <markus.gothe@genexis.eu>");
+MODULE_AUTHOR("Benjamin Larsson <benjamin.larsson@genexis.eu>");
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
+MODULE_DESCRIPTION("Airoha EN7581 PWM driver");
+MODULE_LICENSE("GPL");
--
2.48.1
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