Merge tag 'mfd-next-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd

Pull MFD updates from Lee Jones:
 "Core Framework:
   - Add support for Software Nodes to MFD Core
   - Remove support for Device Properties from MFD Core
   - Use standard APIs in MFD Core

  New Drivers:
   - Add support for ROHM BD9576MUF and BD9573MUF PMICs
   - Add support for Netronix Embedded Controller, PWM and RTC
   - Add support for Actions Semi ATC260x PMICs and OnKey

  New Device Support:
   - Add support for DG1 PCIe Graphics Card to Intel PMT
   - Add support for ROHM BD71815 PMIC to ROHM BD71828
   - Add support for Tolino Shine 2 HD to Netronix Embedded Controller
   - Add support for AX10 BMC Secure Updates to Intel M10 BMC

  Removed Device Support:
   - Remove Arizona Extcon support from MFD
   - Remove ST-E AB8500 Power Supply code from MFD
   - Remove AB3100 altogether

  New Functionality:
   - Add support for SMBus and I2C modes to Dialog DA9063
   - Switch to using Software Nodes in Intel (various)

  New/converted Device Tree bindings:
   - rohm bd71815-pmic, rohm bd9576-pmic, netronix ntxec, actions
     atc260x, ricoh rn5t618, qcom pm8xxx

- Fix-ups:
   - Fix error handling/path; intel_pmt
   - Simplify code; rohm-bd718x7, ab8500-core, intel-m10-bmc
   - Trivial clean-ups (reordering, spelling); rohm-generic, rn5t618,
     max8997
   - Use correct data-type; db8500-prcmu
   - Remove superfluous code; lp87565, intel_quark_i2c_gpi, lpc_sch, twl
   - Use generic APIs/defines; lm3533-core, intel_quark_i2c_gpio
   - Regmap related fix-ups; intel-m10-bmc, sec-core
   - Reorder resource freeing during remove; intel_quark_i2c_gpio
   - Make table indexing more robust; intel_quark_i2c_gpio
   - Fix reference imbalances; arizona-irq
   - Staticify and (un)constify things; arizona-spi, stmpe, ene-kb3930,
     intel-lpss-acpi, intel-lpss-pci, atc260x-i2c, intel_quark_i2c_gpio

  Bug Fixes:
   - Fix incorrect (register) values; intel-m10-bmc
   - Kconfig related fixes; ABX500_CORE
   - Do not clear the Auto Reload Register; stm32-timers"

* tag 'mfd-next-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (84 commits)
  mfd: intel-m10-bmc: Add support for MAX10 BMC Secure Updates
  Revert "mfd: max8997: Add of_compatible to Extcon and Charger mfd_cell"
  mfd: twl: Remove unused inline function twl4030charger_usb_en()
  dt-bindings: mfd: Convert pm8xxx bindings to yaml
  dt-bindings: mfd: Add compatible for pmk8350 rtc
  i2c: designware: Get rid of legacy platform data
  mfd: intel_quark_i2c_gpio: Convert I²C to use software nodes
  mfd: lpc_sch: Partially revert "Add support for Intel Quark X1000"
  mfd: arizona: Fix rumtime PM imbalance on error
  mfd: max8997: Replace 8998 with 8997
  mfd: core: Use acpi_find_child_device() for child devices lookup
  mfd: intel_quark_i2c_gpio: Don't play dirty trick with const
  mfd: intel_quark_i2c_gpio: Enable MSI interrupt
  mfd: intel_quark_i2c_gpio: Reuse BAR definitions for MFD cell indexing
  mfd: ntxec: Support for EC in Tolino Shine 2 HD
  mfd: stm32-timers: Avoid clearing auto reload register
  mfd: intel_quark_i2c_gpio: Replace I²C speeds with descriptive definitions
  mfd: intel_quark_i2c_gpio: Remove unused struct device member
  mfd: intel_quark_i2c_gpio: Unregister resources in reversed order
  mfd: Kconfig: ABX500_CORE should depend on ARCH_U8500
  ...

3 files changed, 193 insertions, 0 deletions

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 43d9f1884cd3..d3371ac7b871 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -393,6 +393,14 @@ config PWM_MXS
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-mxs.
 
+config PWM_NTXEC
+	tristate "Netronix embedded controller PWM support"
+	depends on MFD_NTXEC
+	help
+	  Say yes here if you want to support the PWM output of the embedded
+	  controller found in certain e-book readers designed by the original
+	  design manufacturer Netronix.
+
 config PWM_OMAP_DMTIMER
 	tristate "OMAP Dual-Mode Timer PWM support"
 	depends on OF
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 211db810c439..d3879619bd76 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_PWM_MESON)		+= pwm-meson.o
 obj-$(CONFIG_PWM_MEDIATEK)	+= pwm-mediatek.o
 obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
+obj-$(CONFIG_PWM_NTXEC)		+= pwm-ntxec.o
 obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
diff --git a/drivers/pwm/pwm-ntxec.c b/drivers/pwm/pwm-ntxec.c
new file mode 100644
index 000000000000..50c454c553c4
--- /dev/null
+++ b/drivers/pwm/pwm-ntxec.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * The Netronix embedded controller is a microcontroller found in some
+ * e-book readers designed by the original design manufacturer Netronix, Inc.
+ * It contains RTC, battery monitoring, system power management, and PWM
+ * functionality.
+ *
+ * This driver implements PWM output.
+ *
+ * Copyright 2020 Jonathan Neuschäfer <j.neuschaefer@gmx.net>
+ *
+ * Limitations:
+ * - The get_state callback is not implemented, because the current state of
+ *   the PWM output can't be read back from the hardware.
+ * - The hardware can only generate normal polarity output.
+ * - The period and duty cycle can't be changed together in one atomic action.
+ */
+
+#include <linux/mfd/ntxec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct ntxec_pwm {
+	struct device *dev;
+	struct ntxec *ec;
+	struct pwm_chip chip;
+};
+
+static struct ntxec_pwm *ntxec_pwm_from_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct ntxec_pwm, chip);
+}
+
+#define NTXEC_REG_AUTO_OFF_HI	0xa1
+#define NTXEC_REG_AUTO_OFF_LO	0xa2
+#define NTXEC_REG_ENABLE	0xa3
+#define NTXEC_REG_PERIOD_LOW	0xa4
+#define NTXEC_REG_PERIOD_HIGH	0xa5
+#define NTXEC_REG_DUTY_LOW	0xa6
+#define NTXEC_REG_DUTY_HIGH	0xa7
+
+/*
+ * The time base used in the EC is 8MHz, or 125ns. Period and duty cycle are
+ * measured in this unit.
+ */
+#define TIME_BASE_NS 125
+
+/*
+ * The maximum input value (in nanoseconds) is determined by the time base and
+ * the range of the hardware registers that hold the converted value.
+ * It fits into 32 bits, so we can do our calculations in 32 bits as well.
+ */
+#define MAX_PERIOD_NS (TIME_BASE_NS * 0xffff)
+
+static int ntxec_pwm_set_raw_period_and_duty_cycle(struct pwm_chip *chip,
+						   int period, int duty)
+{
+	struct ntxec_pwm *priv = ntxec_pwm_from_chip(chip);
+
+	/*
+	 * Changes to the period and duty cycle take effect as soon as the
+	 * corresponding low byte is written, so the hardware may be configured
+	 * to an inconsistent state after the period is written and before the
+	 * duty cycle is fully written. If, in such a case, the old duty cycle
+	 * is longer than the new period, the EC may output 100% for a moment.
+	 *
+	 * To minimize the time between the changes to period and duty cycle
+	 * taking effect, the writes are interleaved.
+	 */
+
+	struct reg_sequence regs[] = {
+		{ NTXEC_REG_PERIOD_HIGH, ntxec_reg8(period >> 8) },
+		{ NTXEC_REG_DUTY_HIGH, ntxec_reg8(duty >> 8) },
+		{ NTXEC_REG_PERIOD_LOW, ntxec_reg8(period) },
+		{ NTXEC_REG_DUTY_LOW, ntxec_reg8(duty) },
+	};
+
+	return regmap_multi_reg_write(priv->ec->regmap, regs, ARRAY_SIZE(regs));
+}
+
+static int ntxec_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm_dev,
+			   const struct pwm_state *state)
+{
+	struct ntxec_pwm *priv = ntxec_pwm_from_chip(chip);
+	unsigned int period, duty;
+	int res;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	period = min_t(u64, state->period, MAX_PERIOD_NS);
+	duty   = min_t(u64, state->duty_cycle, period);
+
+	period /= TIME_BASE_NS;
+	duty   /= TIME_BASE_NS;
+
+	/*
+	 * Writing a duty cycle of zero puts the device into a state where
+	 * writing a higher duty cycle doesn't result in the brightness that it
+	 * usually results in. This can be fixed by cycling the ENABLE register.
+	 *
+	 * As a workaround, write ENABLE=0 when the duty cycle is zero.
+	 * The case that something has previously set the duty cycle to zero
+	 * but ENABLE=1, is not handled.
+	 */
+	if (state->enabled && duty != 0) {
+		res = ntxec_pwm_set_raw_period_and_duty_cycle(chip, period, duty);
+		if (res)
+			return res;
+
+		res = regmap_write(priv->ec->regmap, NTXEC_REG_ENABLE, ntxec_reg8(1));
+		if (res)
+			return res;
+
+		/* Disable the auto-off timer */
+		res = regmap_write(priv->ec->regmap, NTXEC_REG_AUTO_OFF_HI, ntxec_reg8(0xff));
+		if (res)
+			return res;
+
+		return regmap_write(priv->ec->regmap, NTXEC_REG_AUTO_OFF_LO, ntxec_reg8(0xff));
+	} else {
+		return regmap_write(priv->ec->regmap, NTXEC_REG_ENABLE, ntxec_reg8(0));
+	}
+}
+
+static const struct pwm_ops ntxec_pwm_ops = {
+	.owner = THIS_MODULE,
+	.apply = ntxec_pwm_apply,
+	/*
+	 * No .get_state callback, because the current state cannot be read
+	 * back from the hardware.
+	 */
+};
+
+static int ntxec_pwm_probe(struct platform_device *pdev)
+{
+	struct ntxec *ec = dev_get_drvdata(pdev->dev.parent);
+	struct ntxec_pwm *priv;
+	struct pwm_chip *chip;
+
+	pdev->dev.of_node = pdev->dev.parent->of_node;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->ec = ec;
+	priv->dev = &pdev->dev;
+
+	platform_set_drvdata(pdev, priv);
+
+	chip = &priv->chip;
+	chip->dev = &pdev->dev;
+	chip->ops = &ntxec_pwm_ops;
+	chip->base = -1;
+	chip->npwm = 1;
+
+	return pwmchip_add(chip);
+}
+
+static int ntxec_pwm_remove(struct platform_device *pdev)
+{
+	struct ntxec_pwm *priv = platform_get_drvdata(pdev);
+	struct pwm_chip *chip = &priv->chip;
+
+	return pwmchip_remove(chip);
+}
+
+static struct platform_driver ntxec_pwm_driver = {
+	.driver = {
+		.name = "ntxec-pwm",
+	},
+	.probe = ntxec_pwm_probe,
+	.remove = ntxec_pwm_remove,
+};
+module_platform_driver(ntxec_pwm_driver);
+
+MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
+MODULE_DESCRIPTION("PWM driver for Netronix EC");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ntxec-pwm");