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Message-Id: <20210212131910.557581-3-nobuhiro1.iwamatsu@toshiba.co.jp>
Date: Fri, 12 Feb 2021 22:19:10 +0900
From: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
To: Rob Herring <robh+dt@...nel.org>,
Thierry Reding <thierry.reding@...il.com>,
Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>, Lee Jones <lee.jones@...aro.org>
Cc: devicetree@...r.kernel.org, linux-pwm@...r.kernel.org,
punit1.agrawal@...hiba.co.jp, yuji2.ishikawa@...hiba.co.jp,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
Subject: [PATCH v2 2/2] pwm: visconti: Add Toshiba Visconti SoC PWM support
Add driver for the PWM controller on Toshiba Visconti ARM SoC.
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
---
drivers/pwm/Kconfig | 9 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-visconti.c | 173 +++++++++++++++++++++++++++++++++++++
3 files changed, 183 insertions(+)
create mode 100644 drivers/pwm/pwm-visconti.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 9a4f66ae8070..8ae68d6203fb 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -601,6 +601,15 @@ config PWM_TWL_LED
To compile this driver as a module, choose M here: the module
will be called pwm-twl-led.
+config PWM_VISCONTI
+ tristate "Toshiba Visconti PWM support"
+ depends on ARCH_VISCONTI || COMPILE_TEST
+ help
+ PWM Subsystem driver support for Toshiba Visconti SoCs.
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-visconti.
+
config PWM_VT8500
tristate "vt8500 PWM support"
depends on ARCH_VT8500 || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 6374d3b1d6f3..d43b1e17e8e1 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -56,4 +56,5 @@ obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
obj-$(CONFIG_PWM_TWL) += pwm-twl.o
obj-$(CONFIG_PWM_TWL_LED) += pwm-twl-led.o
+obj-$(CONFIG_PWM_VISCONTI) += pwm-visconti.o
obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o
diff --git a/drivers/pwm/pwm-visconti.c b/drivers/pwm/pwm-visconti.c
new file mode 100644
index 000000000000..2aa140f1ec04
--- /dev/null
+++ b/drivers/pwm/pwm-visconti.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Toshiba Visconti pulse-width-modulation controller driver
+ *
+ * Copyright (c) 2020 TOSHIBA CORPORATION
+ * Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation
+ *
+ * Authors: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/pwm.h>
+#include <linux/platform_device.h>
+
+
+#define PIPGM_PCSR(ch) (0x400 + 4 * (ch))
+#define PIPGM_PDUT(ch) (0x420 + 4 * (ch))
+#define PIPGM_PWMC(ch) (0x440 + 4 * (ch))
+
+#define PIPGM_PWMC_PWMACT BIT(5)
+#define PIPGM_PWMC_CLK_MASK GENMASK(1, 0)
+#define PIPGM_PWMC_POLARITY_MASK GENMASK(5, 5)
+#define PIPGM_PDUT_MAX 0xFFFF
+
+struct visconti_pwm_chip {
+ struct pwm_chip chip;
+ void __iomem *base;
+};
+
+#define to_visconti_chip(chip) \
+ container_of(chip, struct visconti_pwm_chip, chip)
+
+static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct visconti_pwm_chip *priv = to_visconti_chip(chip);
+ u32 period, duty, pwmc0;
+
+ dev_dbg(chip->dev, "%s: ch = %d en = %d p = 0x%llx d = 0x%llx\n", __func__,
+ pwm->hwpwm, state->enabled, state->period, state->duty_cycle);
+
+ /*
+ * pwmc is a 2-bit divider for the input clock running at 1 MHz.
+ * When the settings of the PWM are modified, the new values are shadowed in hardware until
+ * the period register (PCSR) is written and the currently running period is completed. This
+ * way the hardware switches atomically from the old setting to the new.
+ * Also, disabling the hardware completes the currently running period and keeps the output
+ * at low level at all times.
+ */
+ if (!state->enabled) {
+ writel(0, priv->base + PIPGM_PCSR(pwm->hwpwm));
+ return 0;
+ }
+
+ period = state->period / NSEC_PER_USEC;
+ duty = state->duty_cycle / NSEC_PER_USEC;
+ if (period < 0x10000)
+ pwmc0 = 0;
+ else if (period < 0x20000)
+ pwmc0 = 1;
+ else if (period < 0x40000)
+ pwmc0 = 2;
+ else if (period < 0x80000)
+ pwmc0 = 3;
+ else
+ return -EINVAL;
+
+ if (duty > PIPGM_PDUT_MAX)
+ return -EINVAL;
+
+ period >>= pwmc0;
+ duty >>= pwmc0;
+
+ if (state->polarity == PWM_POLARITY_INVERSED)
+ pwmc0 |= PIPGM_PWMC_PWMACT;
+
+ writel(pwmc0, priv->base + PIPGM_PWMC(pwm->hwpwm));
+ writel(duty, priv->base + PIPGM_PDUT(pwm->hwpwm));
+ writel(period, priv->base + PIPGM_PCSR(pwm->hwpwm));
+
+ return 0;
+}
+
+static void visconti_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+ struct pwm_state *state)
+{
+ struct visconti_pwm_chip *priv = to_visconti_chip(chip);
+ u32 period, duty, pwmc0, pwmc0_clk;
+
+ period = readl(priv->base + PIPGM_PCSR(pwm->hwpwm));
+ if (period)
+ state->enabled = true;
+ else
+ state->enabled = false;
+
+ duty = readl(priv->base + PIPGM_PDUT(pwm->hwpwm));
+ pwmc0 = readl(priv->base + PIPGM_PWMC(pwm->hwpwm));
+ pwmc0_clk = pwmc0 & PIPGM_PWMC_CLK_MASK;
+
+ state->period = (period << pwmc0_clk) * NSEC_PER_USEC;
+ state->duty_cycle = (duty << pwmc0_clk) * NSEC_PER_USEC;
+ if (pwmc0 & PIPGM_PWMC_POLARITY_MASK)
+ state->polarity = PWM_POLARITY_INVERSED;
+ else
+ state->polarity = PWM_POLARITY_NORMAL;
+}
+
+static const struct pwm_ops visconti_pwm_ops = {
+ .apply = visconti_pwm_apply,
+ .get_state = visconti_pwm_get_state,
+ .owner = THIS_MODULE,
+};
+
+static int visconti_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct visconti_pwm_chip *priv;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ platform_set_drvdata(pdev, priv);
+
+ priv->chip.dev = dev;
+ priv->chip.ops = &visconti_pwm_ops;
+ priv->chip.base = -1;
+ priv->chip.npwm = 4;
+
+ ret = pwmchip_add(&priv->chip);
+ if (ret < 0)
+ return dev_err_probe(&pdev->dev, ret, "Cannot register visconti PWM\n");
+
+ dev_dbg(&pdev->dev, "visconti PWM registered\n");
+
+ return 0;
+}
+
+static int visconti_pwm_remove(struct platform_device *pdev)
+{
+ struct visconti_pwm_chip *priv = platform_get_drvdata(pdev);
+
+ return pwmchip_remove(&priv->chip);
+}
+
+static const struct of_device_id visconti_pwm_of_match[] = {
+ { .compatible = "toshiba,pwm-visconti", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, visconti_pwm_of_match);
+
+static struct platform_driver visconti_pwm_driver = {
+ .driver = {
+ .name = "pwm-visconti",
+ .of_match_table = visconti_pwm_of_match,
+ },
+ .probe = visconti_pwm_probe,
+ .remove = visconti_pwm_remove,
+};
+module_platform_driver(visconti_pwm_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>");
+MODULE_ALIAS("platform:visconti-pwm");
--
2.30.0.rc2
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