linux/drivers/pwm/pwm-meson.c

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/*
* 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;
pwm: meson: Handle unknown ID values When building with -Wmaybe-uninitialized, we get a couple of harmless warnings about three functions in this new driver that don't look safe to the compiler: drivers/pwm/pwm-meson.c: In function 'meson_pwm_get_state': drivers/pwm/pwm-meson.c:355:26: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_disable': drivers/pwm/pwm-meson.c:263:13: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_apply': drivers/pwm/pwm-meson.c:231:13: error: 'clk_shift' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:36: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:24: error: 'clk_enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] Specifically, if we have a device with an ID other than 0 or 1, this would result in undefined behavior. This is currently not possible, but the compiler cannot be expected to know this. This patch adds a 'default' clause to let the compiler know what to do instead, which shuts up the warning and makes the code slightly more resiliant in case it gets extended to other identifiers. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-06 12:50:47 +00:00
default:
return;
}
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;
pwm: meson: Handle unknown ID values When building with -Wmaybe-uninitialized, we get a couple of harmless warnings about three functions in this new driver that don't look safe to the compiler: drivers/pwm/pwm-meson.c: In function 'meson_pwm_get_state': drivers/pwm/pwm-meson.c:355:26: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_disable': drivers/pwm/pwm-meson.c:263:13: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_apply': drivers/pwm/pwm-meson.c:231:13: error: 'clk_shift' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:36: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:24: error: 'clk_enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] Specifically, if we have a device with an ID other than 0 or 1, this would result in undefined behavior. This is currently not possible, but the compiler cannot be expected to know this. This patch adds a 'default' clause to let the compiler know what to do instead, which shuts up the warning and makes the code slightly more resiliant in case it gets extended to other identifiers. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-06 12:50:47 +00:00
default:
return;
}
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;
pwm: meson: Handle unknown ID values When building with -Wmaybe-uninitialized, we get a couple of harmless warnings about three functions in this new driver that don't look safe to the compiler: drivers/pwm/pwm-meson.c: In function 'meson_pwm_get_state': drivers/pwm/pwm-meson.c:355:26: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_disable': drivers/pwm/pwm-meson.c:263:13: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c: In function 'meson_pwm_apply': drivers/pwm/pwm-meson.c:231:13: error: 'clk_shift' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:36: error: 'enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/pwm/pwm-meson.c:231:24: error: 'clk_enable' may be used uninitialized in this function [-Werror=maybe-uninitialized] Specifically, if we have a device with an ID other than 0 or 1, this would result in undefined behavior. This is currently not possible, but the compiler cannot be expected to know this. This patch adds a 'default' clause to let the compiler know what to do instead, which shuts up the warning and makes the code slightly more resiliant in case it gets extended to other identifiers. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2016-09-06 12:50:47 +00:00
default:
return;
}
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);
spin_lock_init(&meson->lock);
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_DESCRIPTION("Amlogic Meson PWM Generator driver");
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_LICENSE("Dual BSD/GPL");