[PATCH] pwm: Add driver for Amlogic Meson PWM controller
Neil Armstrong
narmstrong at baylibre.com
Mon Oct 5 18:02:42 CEST 2020
On 02/10/2020 11:09, Neil Armstrong via groups.io wrote:
> This adds the driver for the PWM controller found in the Amlogic SoCs.
>
> This PWM is only a set of Gates, Dividers and Counters:
> PWM output is achieved by calculating a clock that permits calculating
> two periods (low and high). The counter then has to be set to switch after
> N cycles for the first half period.
> The hardware has no "polarity" setting. This driver reverses the period
> cycles (the low length is inverted with the high length) for
> PWM_POLARITY_INVERSED.
>
> Disabling the PWM stops the output immediately (without waiting for the
> current period to complete first).
>
> Signed-off-by: Neil Armstrong <narmstrong at baylibre.com>
> ---
> drivers/pwm/Kconfig | 7 +
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-meson.c | 528 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 536 insertions(+)
> create mode 100644 drivers/pwm/pwm-meson.c
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 61eb468cde..b3bd5c6bb7 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -23,6 +23,13 @@ config PWM_IMX
> help
> This PWM is found i.MX27 and later i.MX SoCs.
>
> +config PWM_MESON
> + bool "Enable support for Amlogic Meson SoCs PWM"
> + depends on DM_PWM
> + help
> + This PWM is found on Amlogic Meson SoCs. It supports a
> + programmable period and duty cycle for 2 independant channels.
> +
> config PWM_MTK
> bool "Enable support for MediaTek PWM"
> depends on DM_PWM
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 0f4e84b04d..f21ae7d76e 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_DM_PWM) += pwm-uclass.o
>
> obj-$(CONFIG_PWM_EXYNOS) += exynos_pwm.o
> obj-$(CONFIG_PWM_IMX) += pwm-imx.o pwm-imx-util.o
> +obj-$(CONFIG_PWM_MESON) += pwm-meson.o
> obj-$(CONFIG_PWM_MTK) += pwm-mtk.o
> obj-$(CONFIG_PWM_ROCKCHIP) += rk_pwm.o
> obj-$(CONFIG_PWM_SANDBOX) += sandbox_pwm.o
> diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
> new file mode 100644
> index 0000000000..cafb571f16
> --- /dev/null
> +++ b/drivers/pwm/pwm-meson.c
> @@ -0,0 +1,528 @@
> +// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
> +/*
> + * Copyright (C) 2020 BayLibre, SAS.
> + * Author: Neil Armstrong <narmstrong at baylibre.com>
> + * Copyright (C) 2014 Amlogic, Inc.
> + *
> + * This PWM is only a set of Gates, Dividers and Counters:
> + * PWM output is achieved by calculating a clock that permits calculating
> + * two periods (low and high). The counter then has to be set to switch after
> + * N cycles for the first half period.
> + * The hardware has no "polarity" setting. This driver reverses the period
> + * cycles (the low length is inverted with the high length) for
> + * PWM_POLARITY_INVERSED.
> + * Setting the polarity will disable and re-enable the PWM output.
> + * Disabling the PWM stops the output immediately (without waiting for the
> + * current period to complete first).
> + */
> +
> +#include <common.h>
> +#include <clk.h>
> +#include <div64.h>
> +#include <dm.h>
> +#include <pwm.h>
> +#include <regmap.h>
> +#include <linux/io.h>
> +#include <linux/math64.h>
> +#include <linux/bitfield.h>
> +#include <linux/clk-provider.h>
> +
> +#define NSEC_PER_SEC 1000000000L
> +
> +#define REG_PWM_A 0x0
> +#define REG_PWM_B 0x4
> +#define PWM_LOW_MASK GENMASK(15, 0)
> +#define PWM_HIGH_MASK GENMASK(31, 16)
> +
> +#define REG_MISC_AB 0x8
> +#define MISC_B_CLK_EN BIT(23)
> +#define MISC_A_CLK_EN BIT(15)
> +#define MISC_CLK_DIV_MASK 0x7f
> +#define MISC_B_CLK_DIV_SHIFT 16
> +#define MISC_A_CLK_DIV_SHIFT 8
> +#define MISC_B_CLK_SEL_SHIFT 6
> +#define MISC_A_CLK_SEL_SHIFT 4
> +#define MISC_CLK_SEL_MASK 0x3
> +#define MISC_B_EN BIT(1)
> +#define MISC_A_EN BIT(0)
> +
> +#define MESON_NUM_PWMS 2
> +
> +static struct meson_pwm_channel_data {
> + u8 reg_offset;
> + u8 clk_sel_shift;
> + u8 clk_div_shift;
> + u32 clk_en_mask;
> + u32 pwm_en_mask;
> +} meson_pwm_per_channel_data[MESON_NUM_PWMS] = {
> + {
> + .reg_offset = REG_PWM_A,
> + .clk_sel_shift = MISC_A_CLK_SEL_SHIFT,
> + .clk_div_shift = MISC_A_CLK_DIV_SHIFT,
> + .clk_en_mask = MISC_A_CLK_EN,
> + .pwm_en_mask = MISC_A_EN,
> + },
> + {
> + .reg_offset = REG_PWM_B,
> + .clk_sel_shift = MISC_B_CLK_SEL_SHIFT,
> + .clk_div_shift = MISC_B_CLK_DIV_SHIFT,
> + .clk_en_mask = MISC_B_CLK_EN,
> + .pwm_en_mask = MISC_B_EN,
> + }
> +};
> +
> +struct meson_pwm_channel {
> + unsigned int hi;
> + unsigned int lo;
> + u8 pre_div;
> + uint period_ns;
> + uint duty_ns;
> + bool configured;
> + bool enabled;
> + bool polarity;
> + struct clk clk;
> +};
> +
> +struct meson_pwm_data {
> + const long *parent_ids;
> + unsigned int num_parents;
> +};
> +
> +struct meson_pwm {
> + const struct meson_pwm_data *data;
> + struct meson_pwm_channel channels[MESON_NUM_PWMS];
> + void __iomem *base;
> +};
> +
> +static int meson_pwm_set_enable(struct udevice *dev, uint channel, bool enable);
> +
> +static int meson_pwm_set_config(struct udevice *dev, uint channeln,
> + uint period_ns, uint duty_ns)
> +{
> + struct meson_pwm *priv = dev_get_priv(dev);
> + struct meson_pwm_channel *channel;
> + struct meson_pwm_channel_data *channel_data;
> + unsigned int duty, period, pre_div, cnt, duty_cnt;
> + unsigned long fin_freq;
> +
> + if (channeln >= MESON_NUM_PWMS)
> + return -ENODEV;
> +
> + channel = &priv->channels[channeln];
> + channel_data = &meson_pwm_per_channel_data[channeln];
> +
> + period = period_ns;
> + if (channel->polarity)
> + duty = period_ns - duty_ns;
> + else
> + duty = duty_ns;
> +
> + debug("%s%d: polarity %s duty %d period %d\n", __func__, channeln,
> + channel->polarity ? "true" : "false", duty, period);
> +
> + fin_freq = clk_get_rate(&channel->clk);
> + if (fin_freq == 0) {
> + printf("%s%d: invalid source clock frequency\n", __func__, channeln);
> + return -EINVAL;
> + }
> +
> + debug("%s%d: fin_freq: %lu Hz\n", __func__, channeln, fin_freq);
> +
> + pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL);
> + if (pre_div > MISC_CLK_DIV_MASK) {
> + printf("%s%d: unable to get period pre_div\n", __func__, channeln);
> + return -EINVAL;
> + }
> +
> + cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1));
> + if (cnt > 0xffff) {
> + printf("%s%d: unable to get period cnt\n", __func__, channeln);
> + return -EINVAL;
> + }
> +
> + debug("%s%d: period=%u pre_div=%u cnt=%u\n", __func__, channeln, period, pre_div, cnt);
> +
> + if (duty == period) {
> + channel->pre_div = pre_div;
> + channel->hi = cnt;
> + channel->lo = 0;
> + } else if (duty == 0) {
> + channel->pre_div = pre_div;
> + channel->hi = 0;
> + channel->lo = cnt;
> + } else {
> + /* Then check is we can have the duty with the same pre_div */
> + duty_cnt = div64_u64(fin_freq * (u64)duty, NSEC_PER_SEC * (pre_div + 1));
> + if (duty_cnt > 0xffff) {
> + printf("%s%d: unable to get duty cycle\n", __func__, channeln);
> + return -EINVAL;
> + }
> +
> + debug("%s%d: duty=%u pre_div=%u duty_cnt=%u\n",
> + __func__, channeln, duty, pre_div, duty_cnt);
> +
> + channel->pre_div = pre_div;
> + channel->hi = duty_cnt;
> + channel->lo = cnt - duty_cnt;
> + }
> +
> + channel->period_ns = period_ns;
> + channel->duty_ns = duty_ns;
> + channel->configured = true;
> +
> + if (channel->enabled) {
> + meson_pwm_set_enable(dev, channeln, false);
> + meson_pwm_set_enable(dev, channeln, true);
> + }
> +
> + return 0;
> +}
> +
> +static int meson_pwm_set_enable(struct udevice *dev, uint channeln, bool enable)
> +{
> + struct meson_pwm *priv = dev_get_priv(dev);
> + struct meson_pwm_channel *channel;
> + struct meson_pwm_channel_data *channel_data;
> + u32 value;
> +
> + if (channeln >= MESON_NUM_PWMS)
> + return -ENODEV;
> +
> + channel = &priv->channels[channeln];
> + channel_data = &meson_pwm_per_channel_data[channeln];
> +
> + if (!channel->configured)
> + return -EINVAL;
> +
> + if (enable) {
> + if (channel->enabled)
> + return 0;
> +
> + value = readl(priv->base + REG_MISC_AB);
> + value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift);
> + value |= channel->pre_div << channel_data->clk_div_shift;
> + value |= channel_data->clk_en_mask;
> + writel(value, priv->base + REG_MISC_AB);
> +
> + value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) |
> + FIELD_PREP(PWM_LOW_MASK, channel->lo);
> + writel(value, priv->base + channel_data->reg_offset);
> +
> + value = readl(priv->base + REG_MISC_AB);
> + value |= channel_data->pwm_en_mask;
> + writel(value, priv->base + REG_MISC_AB);
> +
> + debug("%s%d: enabled\n", __func__, channeln);
> + channel->enabled = true;
> + } else {
> + if (!channel->enabled)
> + return 0;
> +
> + value = readl(priv->base + REG_MISC_AB);
> + value &= channel_data->pwm_en_mask;
> + writel(value, priv->base + REG_MISC_AB);
> +
> + debug("%s%d: disabled\n", __func__, channeln);
> + channel->enabled = false;
> + }
> +
> + return 0;
> +}
> +
> +static int meson_pwm_set_invert(struct udevice *dev, uint channeln, bool polarity)
> +{
> + struct meson_pwm *priv = dev_get_priv(dev);
> + struct meson_pwm_channel *channel;
> +
> + if (channeln >= MESON_NUM_PWMS)
> + return -ENODEV;
> +
> + debug("%s%d: set invert %s\n", __func__, channeln, polarity ? "true" : "false");
> +
> + channel = &priv->channels[channeln];
> +
> + channel->polarity = polarity;
> +
> + if (!channel->configured)
> + return 0;
> +
> + return meson_pwm_set_config(dev, channeln, channel->period_ns, channel->duty_ns);
> +}
> +
> +static int meson_pwm_ofdata_to_platdata(struct udevice *dev)
> +{
> + struct meson_pwm *priv = dev_get_priv(dev);
> +
> + priv->base = dev_read_addr_ptr(dev);
> +
> + return 0;
> +}
> +
> +static int meson_pwm_probe(struct udevice *dev)
> +{
> + struct meson_pwm *priv = dev_get_priv(dev);
> + struct meson_pwm_data *data;
> + unsigned int i, p;
> + char name[255];
> + int err;
> + u32 reg;
> +
> + data = (struct meson_pwm_data *)dev_get_driver_data(dev);
> + if (!data)
> + return -EINVAL;
> +
> + for (i = 0; i < MESON_NUM_PWMS; i++) {
> + struct meson_pwm_channel *channel = &priv->channels[i];
> + struct meson_pwm_channel_data *channel_data = &meson_pwm_per_channel_data[i];
> +
> + snprintf(name, sizeof(name), "clkin%u", i);
> +
> + err = clk_get_by_name(dev, name, &channel->clk);
> + /* If clock is not specified, use the already set clock */
> + if (err == -ENODATA) {
> + struct udevice *cdev;
> + struct uclass *uc;
> +
> + /* Get parent from mux */
> + p = (readl(priv->base + REG_MISC_AB) >> channel_data->clk_sel_shift) &
> + MISC_CLK_SEL_MASK;
> +
> + if (p >= data->num_parents) {
> + printf("%s%d: hw parent is invalid\n", __func__, i);
> + return -EINVAL;
> + }
> +
> + if (data->parent_ids[p] == -1) {
> + /* Search for xtal clk */
> + const char *str;
> +
> + err = uclass_get(UCLASS_CLK, &uc);
> + if (err)
> + return err;
> +
> + uclass_foreach_dev(cdev, uc) {
> + if (strcmp(cdev->driver->name, "fixed_rate_clock"))
> + continue;
> +
> + str = ofnode_read_string(cdev->node, "clock-output-names");
> + if (!str)
> + continue;
> +
> + if (!strcmp(str, "xtal")) {
> + err = uclass_get_device_by_ofnode(UCLASS_CLK,
> + cdev->node,
> + &cdev);
> + if (err) {
> + printf("%s%d: Failed to get xtal clk\n", __func__, i);
> + return err;
> + }
> +
> + break;
> + }
> + }
> +
> + if (!cdev) {
> + printf("%s%d: Failed to find xtal clk device\n", __func__, i);
> + return -EINVAL;
> + }
> +
> + channel->clk.dev = cdev;
> + channel->clk.id = 0;
> + channel->clk.data = 0;
> + } else {
> + /* Look for parent clock */
> + err = uclass_get(UCLASS_CLK, &uc);
> + if (err)
> + return err;
> +
> + uclass_foreach_dev(cdev, uc) {
> + if (strstr(cdev->driver->name, "meson_clk"))
> + break;
> + }
> +
> + if (!cdev) {
> + printf("%s%d: Failed to find clk device\n", __func__, i);
> + return -EINVAL;
> + }
> +
> + err = uclass_get_device_by_ofnode(UCLASS_CLK, cdev->node, &cdev);
> + if (err) {
> + printf("%s%d: Failed to get clk controller\n", __func__, i);
> + return err;
> + }
> +
> + channel->clk.dev = cdev;
> + channel->clk.id = data->parent_ids[p];
> + channel->clk.data = 0;
> + }
> +
> + /* We have our source clock, do not alter HW clock mux */
> + continue;
> + } else
> + return err;
> +
> + /* Get id in list */
> + for (p = 0 ; p < data->num_parents ; ++p) {
> + if (!strcmp(channel->clk.dev->driver->name, "fixed_rate_clock")) {
> + if (data->parent_ids[p] == -1)
> + break;
> + } else {
> + if (data->parent_ids[p] == channel->clk.id)
> + break;
> + }
> + }
> +
> + /* Invalid clock ID */
> + if (p == data->num_parents) {
> + printf("%s%d: source clock is invalid\n", __func__, i);
> + return -EINVAL;
> + }
> +
> + /* switch parent in mux */
> + reg = readl(priv->base + REG_MISC_AB);
> +
> + debug("%s%d: switching parent %d to %d\n", __func__, i,
> + (reg >> channel_data->clk_sel_shift) & MISC_CLK_SEL_MASK, p);
> +
> + reg &= MISC_CLK_SEL_MASK << channel_data->clk_sel_shift;
> + reg |= (p & MISC_CLK_SEL_MASK) << channel_data->clk_sel_shift;
> + writel(reg, priv->base + REG_MISC_AB);
> + }
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops meson_pwm_ops = {
> + .set_config = meson_pwm_set_config,
> + .set_enable = meson_pwm_set_enable,
> + .set_invert = meson_pwm_set_invert,
> +};
> +
> +#define XTAL -1
> +
> +/* Local clock ids aliases to avoid define conflicts */
> +#define GXBB_CLKID_HDMI_PLL 2
> +#define GXBB_CLKID_FCLK_DIV3 5
> +#define GXBB_CLKID_FCLK_DIV4 6
> +#define GXBB_CLKID_CLK81 12
> +
> +static const long pwm_gxbb_parent_ids[] = {
> + XTAL, GXBB_CLKID_HDMI_PLL, GXBB_CLKID_FCLK_DIV4, GXBB_CLKID_FCLK_DIV3
> +};
> +
> +static const struct meson_pwm_data pwm_gxbb_data = {
> + .parent_ids = pwm_gxbb_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_gxbb_parent_ids),
> +};
> +
> +/*
> + * Only the 2 first inputs of the GXBB AO PWMs are valid
> + * The last 2 are grounded
> + */
> +static const long pwm_gxbb_ao_parent_ids[] = {
> + XTAL, GXBB_CLKID_CLK81
> +};
> +
> +static const struct meson_pwm_data pwm_gxbb_ao_data = {
> + .parent_ids = pwm_gxbb_ao_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_ids),
> +};
> +
> +/* Local clock ids aliases to avoid define conflicts */
> +#define AXG_CLKID_FCLK_DIV3 3
> +#define AXG_CLKID_FCLK_DIV4 4
> +#define AXG_CLKID_FCLK_DIV5 5
> +#define AXG_CLKID_CLK81 10
> +
> +static const long pwm_axg_ee_parent_ids[] = {
> + XTAL, AXG_CLKID_FCLK_DIV5, AXG_CLKID_FCLK_DIV4, AXG_CLKID_FCLK_DIV3
> +};
> +
> +static const struct meson_pwm_data pwm_axg_ee_data = {
> + .parent_ids = pwm_axg_ee_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_axg_ee_parent_ids),
> +};
> +
> +static const long pwm_axg_ao_parent_ids[] = {
> + AXG_CLKID_CLK81, XTAL, AXG_CLKID_FCLK_DIV4, AXG_CLKID_FCLK_DIV5
> +};
> +
> +static const struct meson_pwm_data pwm_axg_ao_data = {
> + .parent_ids = pwm_axg_ao_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_axg_ao_parent_ids),
> +};
> +
> +/* Local clock ids aliases to avoid define conflicts */
> +#define G12A_CLKID_FCLK_DIV3 3
> +#define G12A_CLKID_FCLK_DIV4 4
> +#define G12A_CLKID_FCLK_DIV5 5
> +#define G12A_CLKID_CLK81 10
> +#define G12A_CLKID_HDMI_PLL 128
> +
> +static const long pwm_g12a_ao_ab_parent_ids[] = {
> + XTAL, G12A_CLKID_CLK81, G12A_CLKID_FCLK_DIV4, G12A_CLKID_FCLK_DIV5
> +};
> +
> +static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
> + .parent_ids = pwm_g12a_ao_ab_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_ids),
> +};
> +
> +static const long pwm_g12a_ao_cd_parent_ids[] = {
> + XTAL, G12A_CLKID_CLK81,
> +};
> +
> +static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
> + .parent_ids = pwm_g12a_ao_cd_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_g12a_ao_cd_parent_ids),
> +};
> +
> +static const long pwm_g12a_ee_parent_ids[] = {
> + XTAL, G12A_CLKID_HDMI_PLL, G12A_CLKID_FCLK_DIV4, G12A_CLKID_FCLK_DIV3
> +};
> +
> +static const struct meson_pwm_data pwm_g12a_ee_data = {
> + .parent_ids = pwm_g12a_ee_parent_ids,
> + .num_parents = ARRAY_SIZE(pwm_g12a_ee_parent_ids),
> +};
> +
> +static const struct udevice_id meson_pwm_ids[] = {
> + {
> + .compatible = "amlogic,meson-gxbb-pwm",
> + .data = (ulong)&pwm_gxbb_data
> + },
> + {
> + .compatible = "amlogic,meson-gxbb-ao-pwm",
> + .data = (ulong)&pwm_gxbb_ao_data
> + },
> + {
> + .compatible = "amlogic,meson-axg-ee-pwm",
> + .data = (ulong)&pwm_axg_ee_data
> + },
> + {
> + .compatible = "amlogic,meson-axg-ao-pwm",
> + .data = (ulong)&pwm_axg_ao_data
> + },
> + {
> + .compatible = "amlogic,meson-g12a-ee-pwm",
> + .data = (ulong)&pwm_g12a_ee_data
> + },
> + {
> + .compatible = "amlogic,meson-g12a-ao-pwm-ab",
> + .data = (ulong)&pwm_g12a_ao_ab_data
> + },
> + {
> + .compatible = "amlogic,meson-g12a-ao-pwm-cd",
> + .data = (ulong)&pwm_g12a_ao_cd_data
> + },
> +};
> +
> +U_BOOT_DRIVER(meson_pwm) = {
> + .name = "meson_pwm",
> + .id = UCLASS_PWM,
> + .of_match = meson_pwm_ids,
> + .ops = &meson_pwm_ops,
> + .ofdata_to_platdata = meson_pwm_ofdata_to_platdata,
> + .probe = meson_pwm_probe,
> + .priv_auto_alloc_size = sizeof(struct meson_pwm),
> +};
>
Applied to u-boot-amlogic
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