* [PATCH v4 2/2] pwm: airoha: Add support for EN7581 SoC
2024-08-20 12:12 [PATCH v4 0/2] Add PWM support to EN7581 Lorenzo Bianconi
2024-08-20 12:12 ` [PATCH v4 1/2] dt-bindings: pwm: Document Airoha EN7581 PWM Lorenzo Bianconi
@ 2024-08-20 12:12 ` Lorenzo Bianconi
1 sibling, 0 replies; 3+ messages in thread
From: Lorenzo Bianconi @ 2024-08-20 12:12 UTC (permalink / raw)
To: Uwe Kleine-König, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Christian Marangi
Cc: linux-pwm, devicetree, lorenzo.bianconi83, linux-arm-kernel,
upstream, angelogioacchino.delregno, ansuelsmth, benjamin.larsson,
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>
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-airoha.c | 408 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 419 insertions(+)
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 3e53838990f5..0a78bda0707d 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -47,6 +47,16 @@ config PWM_AB8500
To compile this driver as a module, choose M here: the module
will be called pwm-ab8500.
+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 0be4f3e6dd43..7ee61822d88d 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -1,6 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_PWM) += core.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.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..8e0b48b21b5e
--- /dev/null
+++ b/drivers/pwm/pwm-airoha.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2022 Markus Gothe <markus.gothe@genexis.eu>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.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_DATE 0x0000
+#define SGPIO_LED_SHIFT_FLAG BIT(31)
+#define SGPIO_LED_DATA GENMASK(16, 0)
+
+#define REG_SGPIO_CLK_DIVR 0x0004
+#define REG_SGPIO_CLK_DLY 0x0008
+
+#define REG_SIPO_FLASH_MODE_CFG 0x000c
+#define SERIAL_GPIO_FLASH_MODE BIT(1)
+#define SERIAL_GPIO_MODE BIT(0)
+
+#define REG_GPIO_FLASH_PRD_SET(_n) (0x0004 + ((_n) << 2))
+#define GPIO_FLASH_PRD_MASK(_n) GENMASK(15 + ((_n) << 4), ((_n) << 4))
+
+#define REG_GPIO_FLASH_MAP(_n) (0x0014 + ((_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) (0x001c + ((_n) << 2))
+
+#define REG_CYCLE_CFG_VALUE(_n) (0x0000 + ((_n) << 2))
+#define WAVE_GEN_CYCLE_MASK(_n) GENMASK(7 + ((_n) << 3), ((_n) << 3))
+
+struct airoha_pwm {
+ void __iomem *sgpio_cfg;
+ void __iomem *flash_cfg;
+ void __iomem *cycle_cfg;
+
+ struct device_node *np;
+ u64 initialized;
+
+ struct {
+ /* Bitmask of PWM channels using this bucket */
+ u64 used;
+ /* Relative duty cycle, 0-255 */
+ u32 duty;
+ /* In 1/250 s, 1-250 permitted */
+ u32 period;
+ } bucket[8];
+};
+
+/*
+ * The first 16 GPIO pins, GPIO0-GPIO15, are mapped into 16 PWM channels, 0-15.
+ * The SIPO GPIO pins are 16 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 4000000
+#define PERIOD_MAX_NS 1000000000
+/* 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, void __iomem *addr,
+ u32 mask, u32 val)
+{
+ val |= (readl(addr) & ~mask);
+ writel(val, addr);
+
+ return val;
+}
+
+#define airoha_pwm_sgpio_rmw(pc, offset, mask, val) \
+ airoha_pwm_rmw((pc), (pc)->sgpio_cfg + (offset), (mask), (val))
+#define airoha_pwm_flash_rmw(pc, offset, mask, val) \
+ airoha_pwm_rmw((pc), (pc)->flash_cfg + (offset), (mask), (val))
+#define airoha_pwm_cycle_rmw(pc, offset, mask, val) \
+ airoha_pwm_rmw((pc), (pc)->cycle_cfg + (offset), (mask), (val))
+
+#define airoha_pwm_sgpio_set(pc, offset, val) \
+ airoha_pwm_sgpio_rmw((pc), (offset), 0, (val))
+#define airoha_pwm_sgpio_clear(pc, offset, mask) \
+ airoha_pwm_sgpio_rmw((pc), (offset), (mask), 0)
+#define airoha_pwm_flash_set(pc, offset, val) \
+ airoha_pwm_flash_rmw((pc), (offset), 0, (val))
+#define airoha_pwm_flash_clear(pc, offset, mask) \
+ airoha_pwm_flash_rmw((pc), (offset), (mask), 0)
+
+static int airoha_pwm_get_waveform(struct airoha_pwm *pc, u32 duty, u32 period)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(pc->bucket); i++) {
+ if (!pc->bucket[i].used)
+ continue;
+
+ if (duty == pc->bucket[i].duty &&
+ period == pc->bucket[i].period)
+ 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 == DUTY_FULL && pc->bucket[i].duty == DUTY_FULL)
+ return i;
+ }
+
+ return -1;
+}
+
+static void airoha_pwm_free_waveform(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_waveform(struct airoha_pwm *pc, u32 duty,
+ u32 period, unsigned int hwpwm)
+{
+ int id = airoha_pwm_get_waveform(pc, duty, period);
+
+ 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_free_waveform(pc, hwpwm);
+ pc->bucket[id].used |= BIT_ULL(hwpwm);
+ pc->bucket[id].period = period;
+ pc->bucket[id].duty = duty;
+ }
+
+ 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_sgpio_set(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_MODE);
+ else
+ airoha_pwm_sgpio_clear(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->sgpio_cfg + 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->sgpio_cfg + 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->sgpio_cfg + REG_SGPIO_LED_DATE, val,
+ !(val & SGPIO_LED_SHIFT_FLAG), 10,
+ 200 * USEC_PER_MSEC))
+ return -ETIMEDOUT;
+
+ airoha_pwm_sgpio_clear(pc, REG_SGPIO_LED_DATE, SGPIO_LED_DATA);
+ if (readl_poll_timeout(pc->sgpio_cfg + REG_SGPIO_LED_DATE, val,
+ !(val & SGPIO_LED_SHIFT_FLAG), 10,
+ 200 * USEC_PER_MSEC))
+ return -ETIMEDOUT;
+
+ /* Set SIPO in PWM mode */
+ airoha_pwm_sgpio_set(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_FLASH_MODE);
+
+ return 0;
+}
+
+static void airoha_pwm_config_waveform(struct airoha_pwm *pc, int index,
+ u32 duty, u32 period)
+{
+ u32 mask, val;
+
+ /* Configure frequency divisor */
+ mask = WAVE_GEN_CYCLE_MASK(index % 4);
+ val = (period << __ffs(mask)) & mask;
+ airoha_pwm_cycle_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_flash_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_flash_clear(pc, addr, GPIO_FLASH_EN(hwpwm % 8));
+ return;
+ }
+
+ mask = GPIO_FLASH_SETID_MASK(hwpwm % 8);
+ val = ((index & 7) << __ffs(mask)) & mask;
+ airoha_pwm_flash_rmw(pc, addr, mask, val);
+ airoha_pwm_flash_set(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,
+ enum pwm_polarity polarity)
+{
+ u32 duty, period;
+ int index = -1;
+
+ duty = clamp_val(div64_u64(DUTY_FULL * duty_ns, period_ns), 0,
+ DUTY_FULL);
+ if (polarity == PWM_POLARITY_INVERSED)
+ duty = DUTY_FULL - duty;
+
+ period = clamp_val(div64_u64(25 * period_ns, 100000000), PERIOD_MIN,
+ PERIOD_MAX);
+ if (duty) {
+ index = airoha_pwm_consume_waveform(pc, duty, period,
+ 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_config_waveform(pc, index, duty, period);
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, index);
+ } else {
+ airoha_pwm_config_flash_map(pc, pwm->hwpwm, index);
+ airoha_pwm_free_waveform(pc, pwm->hwpwm);
+ }
+
+ pc->initialized |= BIT_ULL(pwm->hwpwm);
+
+ return 0;
+}
+
+static void airoha_pwm_free(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_free_waveform(pc, pwm->hwpwm);
+
+ pc->initialized &= ~BIT_ULL(pwm->hwpwm);
+ if (!(pc->initialized >> PWM_NUM_GPIO))
+ airoha_pwm_sgpio_clear(pc, REG_SIPO_FLASH_MODE_CFG,
+ SERIAL_GPIO_FLASH_MODE);
+
+ /*
+ * Clear the state to force re-initialization the next time
+ * this PWM channel is used since we cannot retain state in
+ * hardware due to limited number of waveform generators
+ */
+ memset(&pwm->state, 0, sizeof(pwm->state));
+}
+
+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;
+
+ if (state->period < PERIOD_MIN_NS || state->period > PERIOD_MAX_NS)
+ return -EINVAL;
+
+ return airoha_pwm_config(pc, pwm, duty, state->period,
+ state->polarity);
+}
+
+static const struct pwm_ops airoha_pwm_ops = {
+ .apply = airoha_pwm_apply,
+ .free = airoha_pwm_free,
+};
+
+static int airoha_pwm_probe(struct platform_device *pdev)
+{
+ struct airoha_pwm *pc;
+ struct pwm_chip *chip;
+
+ chip = devm_pwmchip_alloc(&pdev->dev, PWM_NUM_GPIO + PWM_NUM_SIPO,
+ sizeof(*pc));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+
+ pc = pwmchip_get_drvdata(chip);
+ pc->np = pdev->dev.of_node;
+
+ pc->sgpio_cfg = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(pc->sgpio_cfg))
+ return PTR_ERR(pc->sgpio_cfg);
+
+ pc->flash_cfg = devm_platform_ioremap_resource(pdev, 1);
+ if (IS_ERR(pc->flash_cfg))
+ return PTR_ERR(pc->flash_cfg);
+
+ pc->cycle_cfg = devm_platform_ioremap_resource(pdev, 2);
+ if (IS_ERR(pc->cycle_cfg))
+ return PTR_ERR(pc->cycle_cfg);
+
+ chip->ops = &airoha_pwm_ops;
+ chip->of_xlate = of_pwm_xlate_with_flags;
+
+ return devm_pwmchip_add(&pdev->dev, chip);
+}
+
+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 = "airoha-pwm",
+ .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_DESCRIPTION("Airoha EN7581 PWM driver");
+MODULE_LICENSE("GPL");
--
2.46.0
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