[v2 2/2] pwm: Add Aspeed ast2600 PWM support
Billy Tsai
billy_tsai at aspeedtech.com
Wed Apr 14 20:49:39 AEST 2021
This patch add the support of PWM controller which can be found at aspeed
ast2600 soc. The pwm supoorts up to 16 channels and it's part function
of multi-funciton device "pwm-tach controller".
Signed-off-by: Billy Tsai <billy_tsai at aspeedtech.com>
---
drivers/pwm/Kconfig | 7 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-aspeed-g6.c | 324 ++++++++++++++++++++++++++++++++++++
3 files changed, 332 insertions(+)
create mode 100644 drivers/pwm/pwm-aspeed-g6.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 9a4f66ae8070..d6c1e25717d7 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -42,6 +42,13 @@ config PWM_DEBUG
It is expected to introduce some runtime overhead and diagnostic
output to the kernel log, so only enable while working on a driver.
+config PWM_ASPEED_G6
+ tristate "ASPEEDG6 PWM support"
+ depends on ARCH_ASPEED || COMPILE_TEST
+ help
+ This driver provides support for ASPEED G6 PWM controllers.
+
+
config PWM_AB8500
tristate "AB8500 PWM support"
depends on AB8500_CORE && ARCH_U8500
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 6374d3b1d6f3..2d9b4590662e 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_SYSFS) += sysfs.o
+obj-$(CONFIG_PWM_ASPEED_G6) += pwm-aspeed-g6.o
obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
diff --git a/drivers/pwm/pwm-aspeed-g6.c b/drivers/pwm/pwm-aspeed-g6.c
new file mode 100644
index 000000000000..b537a5d7015a
--- /dev/null
+++ b/drivers/pwm/pwm-aspeed-g6.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 ASPEED Technology Inc.
+ *
+ * PWM controller driver for Aspeed ast26xx SoCs.
+ * This drivers doesn't rollback to previous version of aspeed SoCs.
+ *
+ * Hardware Features:
+ * 1. Support up to 16 channels
+ * 2. Support PWM frequency range from 24Hz to 780KHz
+ * 3. Duty cycle from 0 to 100% with 1/256 resolution incremental
+ * 4. Support wdt reset tolerance (Driver not ready)
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sysfs.h>
+#include <linux/reset.h>
+#include <linux/regmap.h>
+#include <linux/bitfield.h>
+#include <linux/slab.h>
+#include <linux/pwm.h>
+/* The channel number of Aspeed pwm controller */
+#define PWM_ASPEED_NR_PWMS 16
+
+/* PWM Control Register */
+#define PWM_ASPEED_CTRL_CH(ch) (((ch * 0x10) + 0x00))
+#define PWM_LOAD_SEL_RISING_AS_WDT BIT(19)
+#define PWM_DUTY_LOAD_AS_WDT_ENABLE BIT(18)
+#define PWM_DUTY_SYNC_DISABLE BIT(17)
+#define PWM_CLK_ENABLE BIT(16)
+#define PWM_LEVEL_OUTPUT BIT(15)
+#define PWM_INVERSE BIT(14)
+#define PWM_OPEN_DRAIN_ENABLE BIT(13)
+#define PWM_PIN_ENABLE BIT(12)
+#define PWM_CLK_DIV_H GENMASK(11, 8)
+#define PWM_CLK_DIV_L GENMASK(7, 0)
+
+/* PWM Duty Cycle Register */
+#define PWM_ASPEED_DUTY_CYCLE_CH(ch) (((ch * 0x10) + 0x04))
+#define PWM_PERIOD GENMASK(31, 24)
+#define PWM_POINT_AS_WDT GENMASK(23, 16)
+#define PWM_FALLING_POINT GENMASK(15, 8)
+#define PWM_RISING_POINT GENMASK(7, 0)
+
+/* PWM fixed value */
+#define PWM_FIXED_PERIOD 0xff
+
+struct aspeed_pwm_data {
+ struct pwm_chip chip;
+ struct clk *clk;
+ struct regmap *regmap;
+ struct reset_control *reset;
+};
+
+static void aspeed_set_pwm_channel_enable(struct regmap *regmap, u8 pwm_channel,
+ bool enable)
+{
+ regmap_update_bits(regmap, PWM_ASPEED_CTRL_CH(pwm_channel),
+ (PWM_CLK_ENABLE | PWM_PIN_ENABLE),
+ enable ? (PWM_CLK_ENABLE | PWM_PIN_ENABLE) : 0);
+}
+/*
+ * The PWM frequency = HCLK(200Mhz) / (clock division L bit *
+ * clock division H bit * (period bit + 1))
+ */
+static void aspeed_set_pwm_freq(struct aspeed_pwm_data *priv,
+ struct pwm_device *pwm, u32 freq)
+{
+ u32 target_div, freq_a_fix_div, out_freq;
+ u32 tmp_div_h, tmp_div_l, diff, min_diff = INT_MAX;
+ u32 div_h = BIT(5) - 1, div_l = BIT(8) - 1;
+ u8 div_found;
+ u32 index = pwm->hwpwm;
+ /* Frequency after fixed divide */
+ freq_a_fix_div = clk_get_rate(priv->clk) / (PWM_FIXED_PERIOD + 1);
+ /*
+ * Use round up to avoid 0 case.
+ * After that the only scenario which can't find divide pair is too slow
+ */
+ target_div = DIV_ROUND_UP(freq_a_fix_div, freq);
+ div_found = 0;
+ /* calculate for target frequency */
+ for (tmp_div_h = 0; tmp_div_h < 0x10; tmp_div_h++) {
+ tmp_div_l = target_div / BIT(tmp_div_h) - 1;
+
+ if (tmp_div_l < 0 || tmp_div_l > 255)
+ continue;
+
+ diff = freq - ((freq_a_fix_div >> tmp_div_h) / (tmp_div_l + 1));
+ if (abs(diff) < abs(min_diff)) {
+ min_diff = diff;
+ div_l = tmp_div_l;
+ div_h = tmp_div_h;
+ div_found = 1;
+ if (diff == 0)
+ break;
+ }
+ }
+ if (div_found == 0) {
+ pr_debug("target freq: %d too slow set minimal frequency\n",
+ freq);
+ }
+ out_freq = freq_a_fix_div / (BIT(div_h) * (div_l + 1));
+ pr_debug("div h %x, l : %x\n", div_h, div_l);
+ pr_debug("hclk %ld, target pwm freq %d, real pwm freq %d\n",
+ clk_get_rate(priv->clk), freq, out_freq);
+
+ regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL_CH(index),
+ (PWM_CLK_DIV_H | PWM_CLK_DIV_L),
+ FIELD_PREP(PWM_CLK_DIV_H, div_h) |
+ FIELD_PREP(PWM_CLK_DIV_L, div_l));
+}
+
+static void aspeed_set_pwm_duty(struct aspeed_pwm_data *priv,
+ struct pwm_device *pwm, u32 duty_pt)
+{
+ u32 index = pwm->hwpwm;
+
+ if (duty_pt == 0) {
+ aspeed_set_pwm_channel_enable(priv->regmap, index, false);
+ } else {
+ regmap_update_bits(priv->regmap,
+ PWM_ASPEED_DUTY_CYCLE_CH(index),
+ PWM_FALLING_POINT,
+ FIELD_PREP(PWM_FALLING_POINT, duty_pt));
+ aspeed_set_pwm_channel_enable(priv->regmap, index, true);
+ }
+}
+
+static void aspeed_set_pwm_polarity(struct aspeed_pwm_data *priv,
+ struct pwm_device *pwm, u8 polarity)
+{
+ u32 index = pwm->hwpwm;
+
+ regmap_update_bits(priv->regmap, PWM_ASPEED_CTRL_CH(index), PWM_INVERSE,
+ (polarity) ? PWM_INVERSE : 0);
+}
+
+static int aspeed_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct device *dev = chip->dev;
+ struct aspeed_pwm_data *priv = dev_get_drvdata(dev);
+ struct pwm_state *channel;
+ u32 index = pwm->hwpwm;
+ /*
+ * Fixed the period to the max value and rising point to 0
+ * for high resolution and simplified frequency calculation.
+ */
+ regmap_update_bits(priv->regmap, PWM_ASPEED_DUTY_CYCLE_CH(index),
+ PWM_PERIOD,
+ FIELD_PREP(PWM_PERIOD, PWM_FIXED_PERIOD));
+
+ regmap_update_bits(priv->regmap, PWM_ASPEED_DUTY_CYCLE_CH(index),
+ PWM_RISING_POINT, 0);
+
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+ if (!channel)
+ return -ENOMEM;
+
+ return pwm_set_chip_data(pwm, channel);
+}
+
+static void aspeed_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct pwm_state *channel = pwm_get_chip_data(pwm);
+
+ kfree(channel);
+}
+
+static inline struct aspeed_pwm_data *
+aspeed_pwm_chip_to_data(struct pwm_chip *c)
+{
+ return container_of(c, struct aspeed_pwm_data, chip);
+}
+
+static int aspeed_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct device *dev = chip->dev;
+ struct aspeed_pwm_data *priv = aspeed_pwm_chip_to_data(chip);
+ struct pwm_state *channel = pwm_get_chip_data(pwm);
+ /* compute the ns to Hz */
+ u32 freq = DIV_ROUND_UP_ULL(1000000000, state->period);
+ u32 duty_pt = DIV_ROUND_UP_ULL(
+ state->duty_cycle * (PWM_FIXED_PERIOD + 1), state->period);
+ dev_dbg(dev, "freq: %d, duty_pt: %d", freq, duty_pt);
+ if (state->enabled) {
+ aspeed_set_pwm_freq(priv, pwm, freq);
+ aspeed_set_pwm_duty(priv, pwm, duty_pt);
+ aspeed_set_pwm_polarity(priv, pwm, state->polarity);
+ } else {
+ aspeed_set_pwm_duty(priv, pwm, 0);
+ }
+ channel->period = state->period;
+ channel->duty_cycle = state->duty_cycle;
+ channel->polarity = state->polarity;
+ channel->enabled = state->enabled;
+
+ return 0;
+}
+
+static void aspeed_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct pwm_state *channel = pwm_get_chip_data(pwm);
+
+ state->period = channel->period;
+ state->duty_cycle = channel->duty_cycle;
+ state->polarity = channel->polarity;
+ state->enabled = channel->enabled;
+}
+
+static const struct pwm_ops aspeed_pwm_ops = {
+ .request = aspeed_pwm_request,
+ .free = aspeed_pwm_free,
+ .apply = aspeed_pwm_apply,
+ .get_state = aspeed_pwm_get_state,
+ .owner = THIS_MODULE,
+};
+
+static int aspeed_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ int ret;
+ struct aspeed_pwm_data *priv;
+ struct device_node *np;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ np = pdev->dev.parent->of_node;
+ if (!of_device_is_compatible(np, "aspeed,ast2600-pwm-tach")) {
+ dev_err(dev, "unsupported pwm device binding\n");
+ return -ENODEV;
+ }
+
+ priv->regmap = syscon_node_to_regmap(np);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(dev, "Couldn't get regmap\n");
+ return -ENODEV;
+ }
+
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return -ENODEV;
+
+ ret = clk_prepare_enable(priv->clk);
+ if (ret) {
+ dev_err(dev, "couldn't enable clock\n");
+ return ret;
+ }
+
+ priv->reset = reset_control_get_shared(dev, NULL);
+ if (IS_ERR(priv->reset)) {
+ dev_err(dev, "can't get aspeed_pwm_tacho reset: %pe\n",
+ ERR_PTR((long)priv->reset));
+ return PTR_ERR(priv->reset);
+ }
+
+ ret = reset_control_deassert(priv->reset);
+ if (ret) {
+ dev_err(&pdev->dev, "cannot deassert reset control: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
+
+ priv->chip.dev = dev;
+ priv->chip.ops = &aspeed_pwm_ops;
+ priv->chip.npwm = PWM_ASPEED_NR_PWMS;
+ priv->chip.of_xlate = of_pwm_xlate_with_flags;
+ priv->chip.of_pwm_n_cells = 3;
+
+ ret = pwmchip_add(&priv->chip);
+ if (ret < 0) {
+ dev_err(dev, "failed to add PWM chip: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+ dev_set_drvdata(dev, priv);
+ return ret;
+}
+
+static int aspeed_pwm_remove(struct platform_device *dev)
+{
+ struct aspeed_pwm_data *priv = platform_get_drvdata(dev);
+
+ reset_control_assert(priv->reset);
+ clk_disable_unprepare(priv->clk);
+
+ return pwmchip_remove(&priv->chip);
+}
+
+static const struct of_device_id of_pwm_match_table[] = {
+ {
+ .compatible = "aspeed,ast2600-pwm",
+ },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_pwm_match_table);
+
+static struct platform_driver aspeed_pwm_driver = {
+ .probe = aspeed_pwm_probe,
+ .remove = aspeed_pwm_remove,
+ .driver = {
+ .name = "aspeed_pwm",
+ .of_match_table = of_pwm_match_table,
+ },
+};
+
+module_platform_driver(aspeed_pwm_driver);
+
+MODULE_AUTHOR("Billy Tsai <billy_tsai at aspeedtech.com>");
+MODULE_DESCRIPTION("ASPEED PWM device driver");
+MODULE_LICENSE("GPL v2");
--
2.25.1
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