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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-28 15:59:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-28 15:59:13 -0700
commit71a5cc28e88b0db69c3f83d4061ad4cc684af09f (patch)
tree3cc40d902e7cba992c27c946f69ef65fc7d2a807 /drivers/pwm
parentbe18cd1fcae2ed7db58d92d20733dfa8aa0a5173 (diff)
parentf9386c91574fe6da9f4fca9a47734816b0db0019 (diff)
downloadlinux-71a5cc28e88b0db69c3f83d4061ad4cc684af09f.tar.bz2
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 ...
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/Kconfig8
-rw-r--r--drivers/pwm/Makefile1
-rw-r--r--drivers/pwm/pwm-ntxec.c184
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");