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pwm: Add support for Meson PWM Controller

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Add support for the PWM controller found in the Amlogic SoCs. This
driver supports the Meson8b and GXBB SoCs.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Neil Armstrong 2016-08-22 17:36:30 +02:00 committed by Thierry Reding
parent 89394cc7c2
commit 211ed63075
3 changed files with 530 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
drivers/pwm/Kconfig
View file

@ -262,6 +262,15 @@ config PWM_LPSS_PLATFORM
To compile this driver as a module, choose M here: the module
will be called pwm-lpss-platform.
config PWM_MESON
tristate "Amlogic Meson PWM driver"
depends on ARCH_MESON
help
The platform driver for Amlogic Meson PWM controller.
To compile this driver as a module, choose M here: the module
will be called pwm-meson.
config PWM_MTK_DISP
tristate "MediaTek display PWM driver"
depends on ARCH_MEDIATEK || COMPILE_TEST

1
drivers/pwm/Makefile
View file

@ -24,6 +24,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o
obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o
obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o
obj-$(CONFIG_PWM_MESON) += pwm-meson.o
obj-$(CONFIG_PWM_MTK_DISP) += pwm-mtk-disp.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_OMAP_DMTIMER) += pwm-omap-dmtimer.o

520
drivers/pwm/pwm-meson.c Normal file
View file

@ -0,0 +1,520 @@
/*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
*
* GPL LICENSE SUMMARY
*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
* Copyright (C) 2014 Amlogic, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
* The full GNU General Public License is included in this distribution
* in the file called COPYING.
*
* BSD LICENSE
*
* Copyright (c) 2016 BayLibre, SAS.
* Author: Neil Armstrong <narmstrong@baylibre.com>
* Copyright (C) 2014 Amlogic, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Intel Corporation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#define REG_PWM_A 0x0
#define REG_PWM_B 0x4
#define PWM_HIGH_SHIFT 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_WIDTH 2
#define MISC_B_EN BIT(1)
#define MISC_A_EN BIT(0)
static const unsigned int mux_reg_shifts[] = {
MISC_A_CLK_SEL_SHIFT,
MISC_B_CLK_SEL_SHIFT
};
struct meson_pwm_channel {
unsigned int hi;
unsigned int lo;
u8 pre_div;
struct pwm_state state;
struct clk *clk_parent;
struct clk_mux mux;
struct clk *clk;
};
struct meson_pwm_data {
const char * const *parent_names;
};
struct meson_pwm {
struct pwm_chip chip;
const struct meson_pwm_data *data;
void __iomem *base;
u8 inverter_mask;
spinlock_t lock;
};
static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
{
return container_of(chip, struct meson_pwm, chip);
}
static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
struct device *dev = chip->dev;
int err;
if (!channel)
return -ENODEV;
if (channel->clk_parent) {
err = clk_set_parent(channel->clk, channel->clk_parent);
if (err < 0) {
dev_err(dev, "failed to set parent %s for %s: %d\n",
__clk_get_name(channel->clk_parent),
__clk_get_name(channel->clk), err);
return err;
}
}
err = clk_prepare_enable(channel->clk);
if (err < 0) {
dev_err(dev, "failed to enable clock %s: %d\n",
__clk_get_name(channel->clk), err);
return err;
}
chip->ops->get_state(chip, pwm, &channel->state);
return 0;
}
static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
if (channel)
clk_disable_unprepare(channel->clk);
}
static int meson_pwm_calc(struct meson_pwm *meson,
struct meson_pwm_channel *channel, unsigned int id,
unsigned int duty, unsigned int period)
{
unsigned int pre_div, cnt, duty_cnt;
unsigned long fin_freq = -1, fin_ns;
if (~(meson->inverter_mask >> id) & 0x1)
duty = period - duty;
if (period == channel->state.period &&
duty == channel->state.duty_cycle)
return 0;
fin_freq = clk_get_rate(channel->clk);
if (fin_freq == 0) {
dev_err(meson->chip.dev, "invalid source clock frequency\n");
return -EINVAL;
}
dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
fin_ns = NSEC_PER_SEC / fin_freq;
/* Calc pre_div with the period */
for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
cnt = DIV_ROUND_CLOSEST(period, fin_ns * (pre_div + 1));
dev_dbg(meson->chip.dev, "fin_ns=%lu pre_div=%u cnt=%u\n",
fin_ns, pre_div, cnt);
if (cnt <= 0xffff)
break;
}
if (pre_div == MISC_CLK_DIV_MASK) {
dev_err(meson->chip.dev, "unable to get period pre_div\n");
return -EINVAL;
}
dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", 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 = DIV_ROUND_CLOSEST(duty, fin_ns * (pre_div + 1));
if (duty_cnt > 0xffff) {
dev_err(meson->chip.dev, "unable to get duty cycle\n");
return -EINVAL;
}
dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
duty, pre_div, duty_cnt);
channel->pre_div = pre_div;
channel->hi = duty_cnt;
channel->lo = cnt - duty_cnt;
}
return 0;
}
static void meson_pwm_enable(struct meson_pwm *meson,
struct meson_pwm_channel *channel,
unsigned int id)
{
u32 value, clk_shift, clk_enable, enable;
unsigned int offset;
switch (id) {
case 0:
clk_shift = MISC_A_CLK_DIV_SHIFT;
clk_enable = MISC_A_CLK_EN;
enable = MISC_A_EN;
offset = REG_PWM_A;
break;
case 1:
clk_shift = MISC_B_CLK_DIV_SHIFT;
clk_enable = MISC_B_CLK_EN;
enable = MISC_B_EN;
offset = REG_PWM_B;
break;
}
value = readl(meson->base + REG_MISC_AB);
value &= ~(MISC_CLK_DIV_MASK << clk_shift);
value |= channel->pre_div << clk_shift;
value |= clk_enable;
writel(value, meson->base + REG_MISC_AB);
value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
writel(value, meson->base + offset);
value = readl(meson->base + REG_MISC_AB);
value |= enable;
writel(value, meson->base + REG_MISC_AB);
}
static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
{
u32 value, enable;
switch (id) {
case 0:
enable = MISC_A_EN;
break;
case 1:
enable = MISC_B_EN;
break;
}
value = readl(meson->base + REG_MISC_AB);
value &= ~enable;
writel(value, meson->base + REG_MISC_AB);
}
static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
struct meson_pwm *meson = to_meson_pwm(chip);
unsigned long flags;
int err = 0;
if (!state)
return -EINVAL;
spin_lock_irqsave(&meson->lock, flags);
if (!state->enabled) {
meson_pwm_disable(meson, pwm->hwpwm);
channel->state.enabled = false;
goto unlock;
}
if (state->period != channel->state.period ||
state->duty_cycle != channel->state.duty_cycle ||
state->polarity != channel->state.polarity) {
if (channel->state.enabled) {
meson_pwm_disable(meson, pwm->hwpwm);
channel->state.enabled = false;
}
if (state->polarity != channel->state.polarity) {
if (state->polarity == PWM_POLARITY_NORMAL)
meson->inverter_mask |= BIT(pwm->hwpwm);
else
meson->inverter_mask &= ~BIT(pwm->hwpwm);
}
err = meson_pwm_calc(meson, channel, pwm->hwpwm,
state->duty_cycle, state->period);
if (err < 0)
goto unlock;
channel->state.polarity = state->polarity;
channel->state.period = state->period;
channel->state.duty_cycle = state->duty_cycle;
}
if (state->enabled && !channel->state.enabled) {
meson_pwm_enable(meson, channel, pwm->hwpwm);
channel->state.enabled = true;
}
unlock:
spin_unlock_irqrestore(&meson->lock, flags);
return err;
}
static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct meson_pwm *meson = to_meson_pwm(chip);
u32 value, mask;
if (!state)
return;
switch (pwm->hwpwm) {
case 0:
mask = MISC_A_EN;
break;
case 1:
mask = MISC_B_EN;
break;
}
value = readl(meson->base + REG_MISC_AB);
state->enabled = (value & mask) != 0;
}
static const struct pwm_ops meson_pwm_ops = {
.request = meson_pwm_request,
.free = meson_pwm_free,
.apply = meson_pwm_apply,
.get_state = meson_pwm_get_state,
.owner = THIS_MODULE,
};
static const char * const pwm_meson8b_parent_names[] = {
"xtal", "vid_pll", "fclk_div4", "fclk_div3"
};
static const struct meson_pwm_data pwm_meson8b_data = {
.parent_names = pwm_meson8b_parent_names,
};
static const char * const pwm_gxbb_parent_names[] = {
"xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
};
static const struct meson_pwm_data pwm_gxbb_data = {
.parent_names = pwm_gxbb_parent_names,
};
static const struct of_device_id meson_pwm_matches[] = {
{ .compatible = "amlogic,meson8b-pwm", .data = &pwm_meson8b_data },
{ .compatible = "amlogic,meson-gxbb-pwm", .data = &pwm_gxbb_data },
{},
};
MODULE_DEVICE_TABLE(of, meson_pwm_matches);
static int meson_pwm_init_channels(struct meson_pwm *meson,
struct meson_pwm_channel *channels)
{
struct device *dev = meson->chip.dev;
struct device_node *np = dev->of_node;
struct clk_init_data init;
unsigned int i;
char name[255];
int err;
for (i = 0; i < meson->chip.npwm; i++) {
struct meson_pwm_channel *channel = &channels[i];
snprintf(name, sizeof(name), "%s#mux%u", np->full_name, i);
init.name = name;
init.ops = &clk_mux_ops;
init.flags = CLK_IS_BASIC;
init.parent_names = meson->data->parent_names;
init.num_parents = 1 << MISC_CLK_SEL_WIDTH;
channel->mux.reg = meson->base + REG_MISC_AB;
channel->mux.shift = mux_reg_shifts[i];
channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
channel->mux.flags = 0;
channel->mux.lock = &meson->lock;
channel->mux.table = NULL;
channel->mux.hw.init = &init;
channel->clk = devm_clk_register(dev, &channel->mux.hw);
if (IS_ERR(channel->clk)) {
err = PTR_ERR(channel->clk);
dev_err(dev, "failed to register %s: %d\n", name, err);
return err;
}
snprintf(name, sizeof(name), "clkin%u", i);
channel->clk_parent = devm_clk_get(dev, name);
if (IS_ERR(channel->clk_parent)) {
err = PTR_ERR(channel->clk_parent);
if (err == -EPROBE_DEFER)
return err;
channel->clk_parent = NULL;
}
}
return 0;
}
static void meson_pwm_add_channels(struct meson_pwm *meson,
struct meson_pwm_channel *channels)
{
unsigned int i;
for (i = 0; i < meson->chip.npwm; i++)
pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
}
static int meson_pwm_probe(struct platform_device *pdev)
{
struct meson_pwm_channel *channels;
struct meson_pwm *meson;
struct resource *regs;
int err;
meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
if (!meson)
return -ENOMEM;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
meson->base = devm_ioremap_resource(&pdev->dev, regs);
if (IS_ERR(meson->base))
return PTR_ERR(meson->base);
meson->chip.dev = &pdev->dev;
meson->chip.ops = &meson_pwm_ops;
meson->chip.base = -1;
meson->chip.npwm = 2;
meson->chip.of_xlate = of_pwm_xlate_with_flags;
meson->chip.of_pwm_n_cells = 3;
meson->data = of_device_get_match_data(&pdev->dev);
meson->inverter_mask = BIT(meson->chip.npwm) - 1;
channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
GFP_KERNEL);
if (!channels)
return -ENOMEM;
err = meson_pwm_init_channels(meson, channels);
if (err < 0)
return err;
err = pwmchip_add(&meson->chip);
if (err < 0) {
dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
return err;
}
meson_pwm_add_channels(meson, channels);
platform_set_drvdata(pdev, meson);
return 0;
}
static int meson_pwm_remove(struct platform_device *pdev)
{
struct meson_pwm *meson = platform_get_drvdata(pdev);
return pwmchip_remove(&meson->chip);
}
static struct platform_driver meson_pwm_driver = {
.driver = {
.name = "meson-pwm",
.of_match_table = meson_pwm_matches,
},
.probe = meson_pwm_probe,
.remove = meson_pwm_remove,
};
module_platform_driver(meson_pwm_driver);
MODULE_ALIAS("platform:meson-pwm");
MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_LICENSE("Dual BSD/GPL");