[PATCH v5 5/5] pwm: airoha: Add support for EN7581 SoC
Lorenzo Bianconi
lorenzo at kernel.org
Tue Oct 1 10:29:34 PDT 2024
From: Benjamin Larsson <benjamin.larsson at genexis.eu>
Introduce driver for PWM module available on EN7581 SoC.
Signed-off-by: Benjamin Larsson <benjamin.larsson at genexis.eu>
Co-developed-by: Lorenzo Bianconi <lorenzo at kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo at kernel.org>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-airoha.c | 414 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 425 insertions(+)
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0915c1e7df16..af63c3a7b645 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
+ depends on OF
+ 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 9081e0c0e9e0..fbf7723d8458 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..bab2e15e06e7
--- /dev/null
+++ b/drivers/pwm/pwm-airoha.c
@@ -0,0 +1,414 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2022 Markus Gothe <markus.gothe at genexis.eu>
+ *
+ * Limitations:
+ * - No disable bit, so a disabled PWM is simulated by setting duty_cycle to 0
+ * - 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.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/mfd/airoha-en7581-mfd.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/gpio.h>
+#include <linux/bitops.h>
+#include <asm/div64.h>
+
+#define REG_SGPIO_LED_DATA 0x0024
+#define SGPIO_LED_DATA_SHIFT_FLAG BIT(31)
+#define SGPIO_LED_DATA_DATA GENMASK(16, 0)
+
+#define REG_SGPIO_CLK_DIVR 0x0028
+#define REG_SGPIO_CLK_DLY 0x002c
+
+#define REG_SIPO_FLASH_MODE_CFG 0x0030
+#define SERIAL_GPIO_FLASH_MODE BIT(1)
+#define SERIAL_GPIO_MODE BIT(0)
+
+#define REG_GPIO_FLASH_PRD_SET(_n) (0x003c + ((_n) << 2))
+#define GPIO_FLASH_PRD_MASK(_n) GENMASK(15 + ((_n) << 4), ((_n) << 4))
+
+#define REG_GPIO_FLASH_MAP(_n) (0x004c + ((_n) << 2))
+#define GPIO_FLASH_SETID_MASK(_n) GENMASK(2 + ((_n) << 2), ((_n) << 2))
+#define GPIO_FLASH_EN(_n) BIT(3 + ((_n) << 2))
+
+#define REG_SIPO_FLASH_MAP(_n) (0x0054 + ((_n) << 2))
+
+#define REG_CYCLE_CFG_VALUE(_n) (0x0098 + ((_n) << 2))
+#define WAVE_GEN_CYCLE_MASK(_n) GENMASK(7 + ((_n) << 3), ((_n) << 3))
+
+struct airoha_pwm {
+ void __iomem *base;
+
+ struct device_node *np;
+ u64 initialized;
+
+ struct {
+ /* Bitmask of PWM channels using this bucket */
+ u64 used;
+ u64 period_ns;
+ u64 duty_ns;
+ } bucket[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 PWM_NUM_GPIO 16
+#define PWM_NUM_SIPO 17
+
+/* The PWM hardware supports periods between 4 ms and 1 s */
+#define PERIOD_MIN_NS (4 * NSEC_PER_MSEC)
+#define PERIOD_MAX_NS (1 * NSEC_PER_SEC)
+/* It is represented internally as 1/250 s between 1 and 250 */
+#define PERIOD_MIN 1
+#define PERIOD_MAX 250
+/* Duty cycle is relative with 255 corresponding to 100% */
+#define DUTY_FULL 255
+
+static u32 airoha_pwm_rmw(struct airoha_pwm *pc, u32 addr, u32 mask, u32 val)
+{
+ val |= (readl(pc->base + addr) & ~mask);
+ writel(val, pc->base + addr);
+
+ return val;
+}
+
+#define airoha_pwm_set_bits(pc, addr, val) \
+ airoha_pwm_rmw((pc), (addr), (val), (val))
+
+#define airoha_pwm_clear_bit(pc, addr, mask) \
+ airoha_pwm_rmw(pc, addr, mask, 0)
+
+static int airoha_pwm_get_generator(struct airoha_pwm *pc, u64 duty_ns,
+ u64 period_ns)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pc->bucket); i++) {
+ if (!pc->bucket[i].used)
+ continue;
+
+ if (duty_ns == pc->bucket[i].duty_ns &&
+ period_ns == pc->bucket[i].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
+ */
+ if (duty_ns == DUTY_FULL && pc->bucket[i].duty_ns == DUTY_FULL)
+ return i;
+ }
+
+ return -1;
+}
+
+static void airoha_pwm_release_bucket_config(struct airoha_pwm *pc,
+ unsigned int hwpwm)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pc->bucket); i++)
+ pc->bucket[i].used &= ~BIT_ULL(hwpwm);
+}
+
+static int airoha_pwm_consume_generator(struct airoha_pwm *pc,
+ u64 duty_ns, u64 period_ns,
+ unsigned int hwpwm)
+{
+ int id = airoha_pwm_get_generator(pc, duty_ns, period_ns);
+
+ if (id < 0) {
+ int i;
+
+ /* find an unused waveform generator */
+ for (i = 0; i < ARRAY_SIZE(pc->bucket); i++) {
+ if (!(pc->bucket[i].used & ~BIT_ULL(hwpwm))) {
+ id = i;
+ break;
+ }
+ }
+ }
+
+ if (id >= 0) {
+ airoha_pwm_release_bucket_config(pc, hwpwm);
+ pc->bucket[id].used |= BIT_ULL(hwpwm);
+ pc->bucket[id].period_ns = period_ns;
+ pc->bucket[id].duty_ns = duty_ns;
+ }
+
+ return id;
+}
+
+static int airoha_pwm_sipo_init(struct airoha_pwm *pc)
+{
+ u32 clk_divr_val = 3, sipo_clock_delay = 1;
+ u32 val, sipo_clock_divisor = 32;
+
+ if (!(pc->initialized >> PWM_NUM_GPIO))
+ return 0;
+
+ /* Select the right shift register chip */
+ if (of_property_read_bool(pc->np, "hc74595"))
+ airoha_pwm_set_bits(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_MODE);
+ else
+ airoha_pwm_clear_bit(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_MODE);
+
+ if (!of_property_read_u32(pc->np, "sipo-clock-divisor",
+ &sipo_clock_divisor)) {
+ switch (sipo_clock_divisor) {
+ case 4:
+ clk_divr_val = 0;
+ break;
+ case 8:
+ clk_divr_val = 1;
+ break;
+ case 16:
+ clk_divr_val = 2;
+ break;
+ case 32:
+ clk_divr_val = 3;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+ /* Configure shift register timings */
+ writel(clk_divr_val, pc->base + REG_SGPIO_CLK_DIVR);
+
+ of_property_read_u32(pc->np, "sipo-clock-delay", &sipo_clock_delay);
+ if (sipo_clock_delay < 1 || sipo_clock_delay > sipo_clock_divisor / 2)
+ return -EINVAL;
+
+ /*
+ * The actual delay is sclkdly + 1 so subtract 1 from
+ * sipo-clock-delay to calculate the register value
+ */
+ sipo_clock_delay--;
+ writel(sipo_clock_delay, pc->base + REG_SGPIO_CLK_DLY);
+
+ /*
+ * It it necessary to after muxing explicitly shift out all
+ * zeroes 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)
+ */
+ if (readl_poll_timeout(pc->base + REG_SGPIO_LED_DATA, val,
+ !(val & SGPIO_LED_DATA_SHIFT_FLAG), 10,
+ 200 * USEC_PER_MSEC))
+ return -ETIMEDOUT;
+
+ airoha_pwm_clear_bit(pc, REG_SGPIO_LED_DATA, SGPIO_LED_DATA_DATA);
+ if (readl_poll_timeout(pc->base + REG_SGPIO_LED_DATA, val,
+ !(val & SGPIO_LED_DATA_SHIFT_FLAG), 10,
+ 200 * USEC_PER_MSEC))
+ return -ETIMEDOUT;
+
+ /* Set SIPO in PWM mode */
+ airoha_pwm_set_bits(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_FLASH_MODE);
+
+ return 0;
+}
+
+static void airoha_pwm_calc_bucket_config(struct airoha_pwm *pc, int index,
+ u64 duty_ns, u64 period_ns)
+{
+ u32 period, duty, mask, val;
+ u64 tmp;
+
+ tmp = duty_ns * DUTY_FULL;
+ duty = clamp_val(div64_u64(tmp, period_ns), 0, DUTY_FULL);
+ tmp = period_ns * 25;
+ period = clamp_val(div64_u64(tmp, 100000000), PERIOD_MIN, PERIOD_MAX);
+
+ /* Configure frequency divisor */
+ mask = WAVE_GEN_CYCLE_MASK(index % 4);
+ val = (period << __ffs(mask)) & mask;
+ airoha_pwm_rmw(pc, REG_CYCLE_CFG_VALUE(index / 4), mask, val);
+
+ /* Configure duty cycle */
+ duty = ((DUTY_FULL - duty) << 8) | duty;
+ mask = GPIO_FLASH_PRD_MASK(index % 2);
+ val = (duty << __ffs(mask)) & mask;
+ airoha_pwm_rmw(pc, REG_GPIO_FLASH_PRD_SET(index / 2), mask, val);
+}
+
+static void airoha_pwm_config_flash_map(struct airoha_pwm *pc,
+ unsigned int hwpwm, int index)
+{
+ u32 addr, mask, val;
+
+ if (hwpwm < PWM_NUM_GPIO) {
+ addr = REG_GPIO_FLASH_MAP(hwpwm / 8);
+ } else {
+ addr = REG_SIPO_FLASH_MAP(hwpwm / 8);
+ hwpwm -= PWM_NUM_GPIO;
+ }
+
+ if (index < 0) {
+ /*
+ * Change of waveform takes effect immediately but
+ * disabling has some delay so to prevent glitching
+ * only the enable bit is touched when disabling
+ */
+ airoha_pwm_clear_bit(pc, addr, GPIO_FLASH_EN(hwpwm % 8));
+ return;
+ }
+
+ mask = GPIO_FLASH_SETID_MASK(hwpwm % 8);
+ val = ((index & 7) << __ffs(mask)) & mask;
+ airoha_pwm_rmw(pc, addr, mask, val);
+ airoha_pwm_set_bits(pc, addr, GPIO_FLASH_EN(hwpwm % 8));
+}
+
+static int airoha_pwm_config(struct airoha_pwm *pc, struct pwm_device *pwm,
+ u64 duty_ns, u64 period_ns)
+{
+ int index = -1;
+
+ index = airoha_pwm_consume_generator(pc, duty_ns, period_ns,
+ pwm->hwpwm);
+ if (index < 0)
+ return -EBUSY;
+
+ if (!(pc->initialized & BIT_ULL(pwm->hwpwm)) &&
+ pwm->hwpwm >= PWM_NUM_GPIO)
+ airoha_pwm_sipo_init(pc);
+
+ if (index >= 0) {
+ airoha_pwm_calc_bucket_config(pc, index, duty_ns, period_ns);
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, index);
+ } else {
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, index);
+ airoha_pwm_release_bucket_config(pc, pwm->hwpwm);
+ }
+
+ pc->initialized |= BIT_ULL(pwm->hwpwm);
+
+ return 0;
+}
+
+static void airoha_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct airoha_pwm *pc = pwmchip_get_drvdata(chip);
+
+ /* Disable PWM and release the waveform */
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, -1);
+ airoha_pwm_release_bucket_config(pc, pwm->hwpwm);
+
+ pc->initialized &= ~BIT_ULL(pwm->hwpwm);
+ if (!(pc->initialized >> PWM_NUM_GPIO))
+ airoha_pwm_clear_bit(pc, REG_SIPO_FLASH_MODE_CFG,
+ 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 = state->enabled ? state->duty_cycle : 0;
+ u64 period = state->period;
+
+ /* Only normal polarity is supported */
+ if (state->polarity == PWM_POLARITY_INVERSED)
+ return -EINVAL;
+
+ if (!state->enabled) {
+ airoha_pwm_disable(chip, pwm);
+ return 0;
+ }
+
+ if (period < PERIOD_MIN_NS)
+ return -EINVAL;
+
+ if (period > PERIOD_MAX_NS)
+ period = PERIOD_MAX_NS;
+
+ return airoha_pwm_config(pc, pwm, duty, period);
+}
+
+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 i;
+
+ /* find hwpwm in waveform generator bucket */
+ for (i = 0; i < ARRAY_SIZE(pc->bucket); i++) {
+ if (pc->bucket[i].used & BIT_ULL(pwm->hwpwm)) {
+ state->enabled = pc->initialized & BIT_ULL(pwm->hwpwm);
+ state->polarity = PWM_POLARITY_NORMAL;
+ state->period = pc->bucket[i].period_ns;
+ state->duty_cycle = pc->bucket[i].duty_ns;
+ break;
+ }
+ }
+
+ if (i == ARRAY_SIZE(pc->bucket))
+ state->enabled = false;
+
+ return 0;
+}
+
+static const struct pwm_ops airoha_pwm_ops = {
+ .get_state = airoha_pwm_get_state,
+ .apply = airoha_pwm_apply,
+};
+
+static int airoha_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct airoha_mfd *mfd;
+ struct airoha_pwm *pc;
+ struct pwm_chip *chip;
+
+ /* Assign parent MFD of_node to dev */
+ device_set_of_node_from_dev(dev, dev->parent);
+ mfd = dev_get_drvdata(dev->parent);
+
+ chip = devm_pwmchip_alloc(dev, PWM_NUM_GPIO + PWM_NUM_SIPO,
+ sizeof(*pc));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+
+ pc = pwmchip_get_drvdata(chip);
+ pc->np = dev->of_node;
+ pc->base = mfd->base;
+ chip->ops = &airoha_pwm_ops;
+
+ return devm_pwmchip_add(&pdev->dev, chip);
+}
+
+static struct platform_driver airoha_pwm_driver = {
+ .driver = {
+ .name = "pwm-airoha",
+ },
+ .probe = airoha_pwm_probe,
+};
+module_platform_driver(airoha_pwm_driver);
+
+MODULE_AUTHOR("Lorenzo Bianconi <lorenzo at kernel.org>");
+MODULE_AUTHOR("Markus Gothe <markus.gothe at genexis.eu>");
+MODULE_AUTHOR("Benjamin Larsson <benjamin.larsson at genexis.eu>");
+MODULE_DESCRIPTION("Airoha EN7581 PWM driver");
+MODULE_LICENSE("GPL");
--
2.46.2
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