pwm: Add driver for Amlogic Meson PWM controller

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@baylibre.com>
This commit is contained in:
Neil Armstrong 2020-10-01 10:04:56 +02:00
parent 38c1c6f816
commit 2d481b2e3e
3 changed files with 536 additions and 0 deletions

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@ -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

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@ -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

528
drivers/pwm/pwm-meson.c Normal file
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@ -0,0 +1,528 @@
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
* Copyright (C) 2020 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@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),
};