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Message-Id: <1467698426-27600-3-git-send-email-yendapally.reddy@broadcom.com>
Date: Tue, 5 Jul 2016 02:00:25 -0400
From: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@...adcom.com>
To: Thierry Reding <thierry.reding@...il.com>,
Rob Herring <robh+dt@...nel.org>,
Pawel Moll <pawel.moll@....com>,
Mark Rutland <mark.rutland@....com>,
Ian Campbell <ijc+devicetree@...lion.org.uk>,
Kumar Gala <galak@...eaurora.org>, Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
Jon Mason <jonmason@...adcom.com>,
Russell King <linux@....linux.org.uk>
Cc: linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
bcm-kernel-feedback-list@...adcom.com,
linux-kernel@...r.kernel.org,
Yendapally Reddy Dhananjaya Reddy
<yendapally.reddy@...adcom.com>
Subject: [PATCH v5 2/3] pwm: iproc: Add support for Broadcom iproc pwm controller
Add support for the PWM controller present in Broadcom's iProc
family of SoCs.It has been tested on the Northstar+ bcm958625HR board.
Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@...adcom.com>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-bcm-iproc.c | 268 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 279 insertions(+)
create mode 100644 drivers/pwm/pwm-bcm-iproc.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index c182efc..1339b62 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -74,6 +74,16 @@ config PWM_ATMEL_TCB
To compile this driver as a module, choose M here: the module
will be called pwm-atmel-tcb.
+config PWM_BCM_IPROC
+ tristate "iProc PWM support"
+ depends on ARCH_BCM_IPROC || COMPILE_TEST
+ help
+ Generic PWM framework driver for Broadcom iProc PWM block. This
+ block is used in Broadcom iProc SoC's.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-bcm-iproc.
+
config PWM_BCM_KONA
tristate "Kona PWM support"
depends on ARCH_BCM_MOBILE
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index dd35bc1..a196d79 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o
obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o
obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o
obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o
+obj-$(CONFIG_PWM_BCM_IPROC) += pwm-bcm-iproc.o
obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o
obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o
obj-$(CONFIG_PWM_BERLIN) += pwm-berlin.o
diff --git a/drivers/pwm/pwm-bcm-iproc.c b/drivers/pwm/pwm-bcm-iproc.c
new file mode 100644
index 0000000..aff260c
--- /dev/null
+++ b/drivers/pwm/pwm-bcm-iproc.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) 2016 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define IPROC_PWM_CTRL_OFFSET (0x00)
+#define IPROC_PWM_CTRL_TYPE_SHIFT(chan) (15 + (chan))
+#define IPROC_PWM_CTRL_POLARITY_SHIFT(chan) (8 + (chan))
+#define IPROC_PWM_CTRL_EN_SHIFT(chan) (chan)
+
+#define IPROC_PWM_PERIOD_OFFSET(chan) (0x04 + ((chan) << 3))
+#define IPROC_PWM_PERIOD_MIN (0x02)
+#define IPROC_PWM_PERIOD_MAX (0xffff)
+
+#define IPROC_PWM_DUTY_CYCLE_OFFSET(chan) (0x08 + ((chan) << 3))
+#define IPROC_PWM_DUTY_CYCLE_MIN (0x00)
+#define IPROC_PWM_DUTY_CYCLE_MAX (0xffff)
+
+#define IPROC_PWM_PRESCALE_OFFSET (0x24)
+#define IPROC_PWM_PRESCALE_BITS (0x06)
+#define IPROC_PWM_PRESCALE_SHIFT(chan) ((3 - (chan)) * \
+ IPROC_PWM_PRESCALE_BITS)
+#define IPROC_PWM_PRESCALE_MASK(chan) (IPROC_PWM_PRESCALE_MAX << \
+ IPROC_PWM_PRESCALE_SHIFT(chan))
+#define IPROC_PWM_PRESCALE_MIN (0x00)
+#define IPROC_PWM_PRESCALE_MAX (0x3f)
+
+#define IPROC_PWM_CHANNEL_COUNT (0x04)
+
+struct iproc_pwmc {
+ struct pwm_chip chip;
+ void __iomem *base;
+ struct clk *clk;
+};
+
+static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *_chip)
+{
+ return container_of(_chip, struct iproc_pwmc, chip);
+}
+
+static void iproc_pwmc_enable(struct iproc_pwmc *ip, u32 chan, bool set)
+{
+ unsigned int value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+
+ if (set)
+ value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(chan);
+ else
+ value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(chan));
+ writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+ /* must be a min 400ns delay between clearing and setting enable bit. */
+ ndelay(400);
+}
+
+void iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+ u32 chan = pwm->hwpwm;
+ u64 val, multi, rate;
+ u32 reg_data;
+ u32 prescale;
+
+ rate = clk_get_rate(ip->clk);
+
+ reg_data = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+ if (reg_data & BIT(IPROC_PWM_CTRL_EN_SHIFT(chan)))
+ state->enabled = true;
+ else
+ state->enabled = false;
+
+ if (reg_data & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(chan)))
+ state->polarity = PWM_POLARITY_NORMAL;
+ else
+ state->polarity = PWM_POLARITY_INVERSED;
+
+ reg_data = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+ prescale = reg_data >> IPROC_PWM_PRESCALE_SHIFT(chan);
+ prescale &= IPROC_PWM_PRESCALE_MAX;
+
+ multi = 1000000000;
+
+ reg_data = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(chan));
+ val = (reg_data & IPROC_PWM_PERIOD_MAX) * (prescale + 1) * multi;
+ val = div64_u64(val, rate);
+ state->period = val;
+
+ reg_data = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(chan));
+ val = (reg_data & IPROC_PWM_PERIOD_MAX) * (prescale + 1) * multi;
+ val = div64_u64(val, rate);
+ state->duty_cycle = val;
+}
+
+static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
+ struct iproc_pwmc *ip = to_iproc_pwmc(chip);
+ unsigned int reg_data, chan = pwm->hwpwm;
+ unsigned long period_cnt, duty_cnt;
+ u64 val, div, rate;
+
+ rate = clk_get_rate(ip->clk);
+
+ /*
+ * Find period count, duty count and prescale to suit duty_cycle and
+ * period. This is done according to formulas described below:
+ *
+ * period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
+ * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ *
+ * PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
+ * DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
+ */
+ while (1) {
+ div = 1000000000;
+ div *= 1 + prescale;
+ val = rate * state->period;
+ period_cnt = div64_u64(val, div);
+ val = rate * state->duty_cycle;
+ duty_cnt = div64_u64(val, div);
+
+ if (period_cnt < IPROC_PWM_PERIOD_MIN ||
+ duty_cnt < IPROC_PWM_DUTY_CYCLE_MIN)
+ return -EINVAL;
+
+ if (period_cnt <= IPROC_PWM_PERIOD_MAX &&
+ duty_cnt <= IPROC_PWM_DUTY_CYCLE_MAX)
+ break;
+
+ /* Otherwise, increase prescale and recalculate counts */
+ if (++prescale > IPROC_PWM_PRESCALE_MAX)
+ return -EINVAL;
+ }
+
+ iproc_pwmc_enable(ip, chan, false);
+
+ /* Set prescale */
+ reg_data = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
+ reg_data &= ~IPROC_PWM_PRESCALE_MASK(chan);
+ reg_data |= prescale << IPROC_PWM_PRESCALE_SHIFT(chan);
+ writel(reg_data, ip->base + IPROC_PWM_PRESCALE_OFFSET);
+
+ /* set period and duty cycle */
+ writel(period_cnt, ip->base + IPROC_PWM_PERIOD_OFFSET(chan));
+ writel(duty_cnt, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(chan));
+
+ /* set polarity */
+ reg_data = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+ if (state->polarity == PWM_POLARITY_NORMAL)
+ reg_data |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan);
+ else
+ reg_data &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan));
+ writel(reg_data, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+ if (state->enabled)
+ iproc_pwmc_enable(ip, chan, true);
+
+ return 0;
+}
+
+static const struct pwm_ops iproc_pwm_ops = {
+ .apply = iproc_pwmc_apply,
+ .get_state = iproc_pwmc_get_state,
+};
+
+static int iproc_pwmc_probe(struct platform_device *pdev)
+{
+ struct iproc_pwmc *ip;
+ struct resource *res;
+ unsigned int value;
+ unsigned int chan;
+ int ret;
+
+ ip = devm_kzalloc(&pdev->dev, sizeof(*ip), GFP_KERNEL);
+ if (ip == NULL)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, ip);
+
+ ip->chip.dev = &pdev->dev;
+ ip->chip.ops = &iproc_pwm_ops;
+ ip->chip.base = -1;
+ ip->chip.npwm = IPROC_PWM_CHANNEL_COUNT;
+ ip->chip.of_xlate = of_pwm_xlate_with_flags;
+ ip->chip.of_pwm_n_cells = 3;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ ip->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(ip->base))
+ return PTR_ERR(ip->base);
+
+ ip->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(ip->clk)) {
+ dev_err(&pdev->dev, "failed to get clock: %ld\n",
+ PTR_ERR(ip->clk));
+ return PTR_ERR(ip->clk);
+ }
+
+ ret = clk_prepare_enable(ip->clk);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
+ return ret;
+ }
+
+ /* Set full drive and normal polarity for all channels */
+ value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
+ for (chan = 0; chan < ip->chip.npwm; chan++) {
+ value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(chan));
+ value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(chan);
+ }
+ writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
+
+ ret = pwmchip_add(&ip->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+ clk_disable_unprepare(ip->clk);
+ }
+
+ return ret;
+}
+
+static int iproc_pwmc_remove(struct platform_device *pdev)
+{
+ struct iproc_pwmc *ip = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(ip->clk);
+
+ return pwmchip_remove(&ip->chip);
+}
+
+static const struct of_device_id bcm_iproc_pwmc_dt[] = {
+ { .compatible = "brcm,iproc-pwm" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
+
+static struct platform_driver iproc_pwmc_driver = {
+ .driver = {
+ .name = "bcm-iproc-pwm",
+ .of_match_table = bcm_iproc_pwmc_dt,
+ },
+ .probe = iproc_pwmc_probe,
+ .remove = iproc_pwmc_remove,
+};
+module_platform_driver(iproc_pwmc_driver);
+
+MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@...adcom.com>");
+MODULE_DESCRIPTION("Broadcom iProc PWM driver");
+MODULE_LICENSE("GPL v2");
--
2.1.0
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