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Subject[PATCH v2 1/4] pwm: Add support for Meson PWM Controller
Date
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>
---
drivers/pwm/Kconfig | 9 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-meson.c | 491 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 501 insertions(+)
create mode 100644 drivers/pwm/pwm-meson.c

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c182efc..cad5286 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -245,6 +245,15 @@ 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
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index dd35bc1..3c8843e 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -22,6 +22,7 @@ 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
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
new file mode 100644
index 0000000..9e7ecf5
--- /dev/null
+++ b/drivers/pwm/pwm-meson.c
@@ -0,0 +1,491 @@
+/*
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/clk-provider.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/pwm.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/of.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)
+
+#define PWM_NUM 2
+
+static const unsigned int mux_reg_shifts[PWM_NUM] = {
+ MISC_A_CLK_SEL_SHIFT, MISC_B_CLK_SEL_SHIFT
+};
+
+static const char * const pwm_parents[] = {
+ "xtal", "vid_pll", "fclk_div4", "fclk_div3", NULL
+};
+
+enum pwm_channel {
+ PWM_A = 0,
+ PWM_B,
+};
+
+struct meson_pwm_channel {
+ unsigned int pwm_hi;
+ unsigned int pwm_lo;
+ u8 pwm_pre_div;
+ int period;
+ int duty;
+};
+
+struct meson_pwm_chip {
+ struct platform_device *pdev;
+ struct pwm_chip chip;
+ void __iomem *base;
+ u8 inverter_mask;
+ spinlock_t lock;
+ struct clk *clk_parents[PWM_NUM];
+ struct clk_mux mux[PWM_NUM];
+ struct clk *clk[PWM_NUM];
+};
+
+#define to_meson_pwm_chip(chip) \
+ container_of(chip, struct meson_pwm_chip, chip)
+
+static int meson_pwm_calc(struct meson_pwm_chip *chip,
+ struct meson_pwm_channel *pwm_chan,
+ unsigned int id,
+ int duty_ns, unsigned int period_ns)
+{
+ unsigned int pwm_pre_div;
+ unsigned int pwm_cnt;
+ unsigned int pwm_duty_cnt;
+ unsigned long fin_freq = -1;
+ unsigned long fin_ns;
+ unsigned int i = 0;
+
+ if (duty_ns > period_ns)
+ return -EINVAL;
+
+ switch (id) {
+ case PWM_A:
+ fin_freq = clk_get_rate(chip->clk[0]);
+ break;
+ case PWM_B:
+ fin_freq = clk_get_rate(chip->clk[1]);
+ break;
+ }
+ if (fin_freq <= 0) {
+ dev_err(chip->chip.dev, "invalid source clock frequency\n");
+ return -EINVAL;
+ }
+ dev_dbg(chip->chip.dev, "fin_freq: %luHz\n", fin_freq);
+ fin_ns = NSEC_PER_SEC / fin_freq;
+
+ /* Calc pre_div with the period */
+ for (i = 0; i < MISC_CLK_DIV_MASK; i++) {
+ pwm_pre_div = i;
+ pwm_cnt = DIV_ROUND_CLOSEST(period_ns,
+ fin_ns * (pwm_pre_div + 1));
+ dev_dbg(chip->chip.dev, "fin_ns=%lu pre_div=%d cnt=%d\n",
+ fin_ns, pwm_pre_div, pwm_cnt);
+ if (pwm_cnt <= 0xffff)
+ break;
+ }
+ if (i == MISC_CLK_DIV_MASK) {
+ dev_err(chip->chip.dev, "Unable to get period pre_div");
+ return -EINVAL;
+ }
+ dev_dbg(chip->chip.dev, "period_ns=%d pre_div=%d pwm_cnt=%d\n",
+ period_ns, pwm_pre_div, pwm_cnt);
+
+ if (duty_ns == period_ns) {
+ pwm_chan->pwm_pre_div = pwm_pre_div;
+ pwm_chan->pwm_hi = pwm_cnt;
+ pwm_chan->pwm_lo = 0;
+ } else if (duty_ns == 0) {
+ pwm_chan->pwm_pre_div = pwm_pre_div;
+ pwm_chan->pwm_hi = 0;
+ pwm_chan->pwm_lo = pwm_cnt;
+ } else {
+ /* Then check is we can have the duty with the same pre_div */
+ pwm_duty_cnt = DIV_ROUND_CLOSEST(duty_ns,
+ fin_ns * (pwm_pre_div + 1));
+ if (pwm_cnt > 0xffff) {
+ dev_err(chip->chip.dev, "Unable to get duty period, differences are too high");
+ return -EINVAL;
+ }
+ dev_dbg(chip->chip.dev, "duty_ns=%d pre_div=%d pwm_cnt=%d\n",
+ duty_ns, pwm_pre_div, pwm_duty_cnt);
+
+ pwm_chan->pwm_pre_div = pwm_pre_div;
+ pwm_chan->pwm_hi = pwm_duty_cnt;
+ pwm_chan->pwm_lo = pwm_cnt - pwm_chan->pwm_hi;
+ }
+
+ return 0;
+}
+
+static int meson_pwm_request(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct meson_pwm_channel *pwm_chan;
+
+ pwm_chan = devm_kzalloc(chip->dev, sizeof(*pwm_chan), GFP_KERNEL);
+ if (!pwm_chan)
+ return -ENOMEM;
+
+ pwm_set_chip_data(pwm, pwm_chan);
+
+ return 0;
+}
+
+static void meson_pwm_free(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ devm_kfree(chip->dev, pwm_get_chip_data(pwm));
+ pwm_set_chip_data(pwm, NULL);
+}
+
+static int meson_pwm_enable(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct meson_pwm_chip *pwm_data = to_meson_pwm_chip(chip);
+ unsigned int id = pwm->hwpwm;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pwm_data->lock, flags);
+ switch (id) {
+ case PWM_A:
+ writel(readl(pwm_data->base + REG_MISC_AB) | MISC_A_EN,
+ pwm_data->base + REG_MISC_AB);
+ break;
+
+ case PWM_B:
+ writel(readl(pwm_data->base + REG_MISC_AB) | MISC_B_EN,
+ pwm_data->base + REG_MISC_AB);
+ break;
+
+ default:
+ break;
+ }
+ spin_unlock_irqrestore(&pwm_data->lock, flags);
+
+ return 0;
+}
+
+static void meson_pwm_disable(struct pwm_chip *chip,
+ struct pwm_device *pwm)
+{
+ struct meson_pwm_chip *pwm_data = to_meson_pwm_chip(chip);
+ unsigned int id = pwm->hwpwm;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pwm_data->lock, flags);
+ switch (id) {
+ case PWM_A:
+ writel(readl(pwm_data->base + REG_MISC_AB) & ~MISC_A_EN,
+ pwm_data->base + REG_MISC_AB);
+ break;
+
+ case PWM_B:
+ writel(readl(pwm_data->base + REG_MISC_AB) & ~MISC_B_EN,
+ pwm_data->base + REG_MISC_AB);
+ break;
+
+ default:
+ break;
+ }
+ spin_unlock_irqrestore(&pwm_data->lock, flags);
+}
+
+static int meson_pwm_config(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ int duty_ns,
+ int period_ns)
+{
+ struct meson_pwm_chip *pwm_data = to_meson_pwm_chip(chip);
+ struct meson_pwm_channel *pwm_chan = pwm_get_chip_data(pwm);
+ unsigned int id = pwm->hwpwm;
+ int ret;
+
+ if ((~(pwm_data->inverter_mask >> id) & 0x1))
+ duty_ns = period_ns - duty_ns;
+
+ if (period_ns == pwm_chan->period && duty_ns == pwm_chan->duty)
+ return 0;
+
+ ret = meson_pwm_calc(pwm_data, pwm_chan, id, duty_ns, period_ns);
+ if (ret) {
+ dev_err(chip->dev, "error while calculating pwm parameters\n");
+ return ret;
+ }
+
+ switch (id) {
+ case PWM_A:
+ writel((readl(pwm_data->base + REG_MISC_AB) &
+ ~(MISC_CLK_DIV_MASK << MISC_A_CLK_DIV_SHIFT)) |
+ ((pwm_chan->pwm_pre_div << MISC_A_CLK_DIV_SHIFT) |
+ MISC_A_CLK_EN),
+ pwm_data->base + REG_MISC_AB);
+
+ writel((pwm_chan->pwm_hi << PWM_HIGH_SHIFT) |
+ (pwm_chan->pwm_lo),
+ pwm_data->base + REG_PWM_A);
+ break;
+
+ case PWM_B:
+ writel((readl(pwm_data->base + REG_MISC_AB) &
+ ~(MISC_CLK_DIV_MASK << MISC_B_CLK_DIV_SHIFT)) |
+ ((pwm_chan->pwm_pre_div << MISC_B_CLK_DIV_SHIFT) |
+ MISC_B_CLK_EN),
+ pwm_data->base + REG_MISC_AB);
+
+ writel((pwm_chan->pwm_hi << PWM_HIGH_SHIFT) |
+ (pwm_chan->pwm_lo),
+ pwm_data->base + REG_PWM_B);
+ break;
+
+ default:
+ break;
+ }
+
+ pwm_chan->period = period_ns;
+ pwm_chan->duty = duty_ns;
+
+ return 0;
+}
+
+static int meson_pwm_set_polarity(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ enum pwm_polarity polarity)
+{
+ struct meson_pwm_chip *pwm_data = to_meson_pwm_chip(chip);
+ struct meson_pwm_channel *pwm_chan = pwm_get_chip_data(pwm);
+ bool invert = (polarity == PWM_POLARITY_NORMAL);
+ unsigned long flags;
+
+ spin_lock_irqsave(&pwm_data->lock, flags);
+
+ if (invert)
+ pwm_data->inverter_mask |= BIT(pwm->hwpwm);
+ else
+ pwm_data->inverter_mask &= ~BIT(pwm->hwpwm);
+
+ meson_pwm_config(chip, pwm, pwm_chan->duty, pwm_chan->period);
+
+ spin_unlock_irqrestore(&pwm_data->lock, flags);
+
+ return 0;
+}
+
+static const struct pwm_ops meson_pwm_ops = {
+ .request = meson_pwm_request,
+ .free = meson_pwm_free,
+ .enable = meson_pwm_enable,
+ .disable = meson_pwm_disable,
+ .config = meson_pwm_config,
+ .set_polarity = meson_pwm_set_polarity,
+ .owner = THIS_MODULE,
+};
+
+static const struct of_device_id meson_pwm_matches[] = {
+ { .compatible = "amlogic,meson8b-pwm", },
+ { .compatible = "amlogic,meson-gxbb-pwm", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, meson_pwm_matches);
+
+static int meson_pwm_mux_init(struct meson_pwm_chip *chip)
+{
+ struct device *dev = &chip->pdev->dev;
+ struct clk_init_data init;
+ char clk_name[255];
+ int ret;
+ int i;
+
+ for (i = 0 ; i < PWM_NUM ; ++i) {
+ sprintf(clk_name, "%s#mux%d",
+ of_node_full_name(dev->of_node), i);
+
+ init.name = devm_kstrdup(dev, clk_name, GFP_KERNEL);
+ init.ops = &clk_mux_ops;
+ init.flags = CLK_IS_BASIC;
+ init.parent_names = pwm_parents;
+ init.num_parents = 1 << MISC_CLK_SEL_WIDTH;
+
+ chip->mux[i].reg = chip->base + REG_MISC_AB;
+ chip->mux[i].shift = mux_reg_shifts[i];
+ chip->mux[i].mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
+ chip->mux[i].flags = 0;
+ chip->mux[i].lock = &chip->lock;
+ chip->mux[i].table = NULL;
+ chip->mux[i].hw.init = &init;
+
+ chip->clk[i] = devm_clk_register(dev, &chip->mux[i].hw);
+ if (IS_ERR(chip->clk[i])) {
+ dev_err(dev, "Failed to register %s\n", clk_name);
+ return PTR_ERR(chip->clk[i]);
+ }
+
+ if (chip->clk_parents[i]) {
+ ret = clk_set_parent(chip->clk[i],
+ chip->clk_parents[i]);
+ if (ret) {
+ dev_err(dev, "Failed to set %s parent\n",
+ clk_name);
+ return ret;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int meson_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct meson_pwm_chip *chip;
+ struct resource *res;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (chip == NULL)
+ return -ENOMEM;
+
+ chip->pdev = pdev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ chip->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(chip->base))
+ return PTR_ERR(chip->base);
+
+ chip->clk_parents[0] = devm_clk_get(dev, "clkin0");
+ if (IS_ERR(chip->clk_parents[0])) {
+ if (PTR_ERR(chip->clk_parents[0]) == -EPROBE_DEFER)
+ return PTR_ERR(chip->clk_parents[0]);
+ chip->clk_parents[0] = NULL;
+ }
+
+ chip->clk_parents[1] = devm_clk_get(dev, "clkin1");
+ if (IS_ERR(chip->clk_parents[1])) {
+ if (PTR_ERR(chip->clk_parents[1]) == -EPROBE_DEFER)
+ return PTR_ERR(chip->clk_parents[1]);
+ chip->clk_parents[1] = NULL;
+ }
+
+ ret = meson_pwm_mux_init(chip);
+ if (ret)
+ return ret;
+
+ clk_prepare_enable(chip->clk[0]);
+ clk_prepare_enable(chip->clk[1]);
+
+ chip->chip.dev = dev;
+ chip->chip.ops = &meson_pwm_ops;
+ chip->chip.base = -1;
+ chip->chip.npwm = PWM_NUM;
+ chip->chip.of_xlate = of_pwm_xlate_with_flags;
+ chip->chip.of_pwm_n_cells = 3;
+ chip->inverter_mask = BIT(PWM_NUM) - 1;
+
+ ret = pwmchip_add(&chip->chip);
+ if (ret < 0) {
+ dev_err(dev, "failed to register PWM chip\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, chip);
+
+ return 0;
+}
+
+static int meson_pwm_remove(struct platform_device *pdev)
+{
+ struct meson_pwm_chip *chip = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&chip->chip);
+}
+
+static struct platform_driver meson_pwm_driver = {
+ .driver = {
+ .name = "meson-pwm",
+ .of_match_table = of_match_ptr(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");
--
2.7.0
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