The LCDC IP used by some Atmel SOC's have a multifunction device that include two sub-devices: - pwm - display controller
This driver add support for the pwm sub-device exposing a single PWM device that can be used for backlight.
The driver is based on the pwm-atmel-hlcdc driver.
Signed-off-by: Sam Ravnborg sam@ravnborg.org Cc: Thierry Reding thierry.reding@gmail.com Cc: Boris Brezillon boris.brezillon@free-electrons.com --- drivers/pwm/Kconfig | 13 ++++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-atmel-lcdc.c | 178 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 192 insertions(+) create mode 100644 drivers/pwm/pwm-atmel-lcdc.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index a4d262db9945..3976c1840778 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -62,6 +62,19 @@ config PWM_ATMEL_HLCDC_PWM To compile this driver as a module, choose M here: the module will be called pwm-atmel-hlcdc.
+config PWM_ATMEL_LCDC_PWM + tristate "Atmel LCDC PWM support" + depends on MFD_ATMEL_LCDC + depends on HAVE_CLK + help + Generic PWM framework driver for the PWM output of the LCDC + (Atmel LCD Controller). This PWM output is mainly used + to control the LCD backlight. + The Atmel LCD Controller is found in the at91sam9x family. + + To compile this driver as a module, choose M here: the module + will be called pwm-atmel-lcdc. + config PWM_ATMEL_TCB tristate "Atmel TC Block PWM support" depends on ATMEL_TCLIB && OF diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 9c676a0dadf5..85d884cb0977 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_PWM_SYSFS) += sysfs.o obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o +obj-$(CONFIG_PWM_ATMEL_LCDC_PWM) += pwm-atmel-lcdc.o obj-$(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 diff --git a/drivers/pwm/pwm-atmel-lcdc.c b/drivers/pwm/pwm-atmel-lcdc.c new file mode 100644 index 000000000000..3d528e75cf9f --- /dev/null +++ b/drivers/pwm/pwm-atmel-lcdc.c @@ -0,0 +1,178 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 Sam Ravnborg + * + * Author: Sam Ravnborg sam@ravnborg.org + * + * PWM embedded in the LCD Controller. + * A sub-device of the Atmel LCDC driver. + * + * Based on pwm-atmel-hlcdc which is: + * Copyright (C) 2014 Free Electrons + * Copyright (C) 2014 Atmel + * Author: Boris BREZILLON boris.brezillon@free-electrons.com + */ + +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/clk.h> +#include <linux/pwm.h> + +#include <linux/platform_device.h> +#include <linux/mfd/atmel-lcdc.h> + +struct lcdc_pwm { + struct pwm_chip chip; + struct atmel_mfd_lcdc *mfd_lcdc; +}; + +static inline struct lcdc_pwm *to_lcdc_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct lcdc_pwm, chip); +} + +static int lcdc_pwm_apply(struct pwm_chip *pwm_chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct lcdc_pwm *chip; + int contrast_ctr; + int contrast_val; + int ret; + + chip = to_lcdc_pwm(pwm_chip); + + if (state->enabled) { + contrast_val = pwm_get_relative_duty_cycle(state, + ATMEL_LCDC_CVAL); + ret = regmap_write(chip->mfd_lcdc->regmap, + ATMEL_LCDC_CONTRAST_VAL, contrast_val); + if (ret) + return ret; + + contrast_ctr = ATMEL_LCDC_ENA_PWMENABLE | ATMEL_LCDC_PS_DIV8; + if (state->polarity == PWM_POLARITY_NORMAL) + contrast_ctr |= ATMEL_LCDC_POL_POSITIVE; + else + contrast_ctr |= ATMEL_LCDC_POL_NEGATIVE; + + ret = regmap_write(chip->mfd_lcdc->regmap, + ATMEL_LCDC_CONTRAST_CTR, contrast_ctr); + } else { + contrast_ctr = ATMEL_LCDC_ENA_PWMDISABLE; + ret = regmap_write(chip->mfd_lcdc->regmap, + ATMEL_LCDC_CONTRAST_CTR, contrast_ctr); + } + + return ret; +} + +static const struct pwm_ops lcdc_pwm_ops = { + .apply = lcdc_pwm_apply, + .owner = THIS_MODULE, +}; + +#ifdef CONFIG_PM_SLEEP +static int lcdc_pwm_suspend(struct device *dev) +{ + struct lcdc_pwm *chip = dev_get_drvdata(dev); + + /* Keep the lcdc clock enabled if the PWM is still running. */ + if (pwm_is_enabled(&chip->chip.pwms[0])) + clk_disable_unprepare(chip->mfd_lcdc->lcdc_clk); + + return 0; +} + +static int lcdc_pwm_resume(struct device *dev) +{ + struct lcdc_pwm *chip = dev_get_drvdata(dev); + struct pwm_state state; + int ret; + + pwm_get_state(&chip->chip.pwms[0], &state); + + /* Re-enable the lcdc clock if it was stopped during suspend. */ + if (!state.enabled) { + ret = clk_prepare_enable(chip->mfd_lcdc->lcdc_clk); + if (ret) + return ret; + } + + return lcdc_pwm_apply(&chip->chip, &chip->chip.pwms[0], &state); +} +#endif + +static SIMPLE_DEV_PM_OPS(lcdc_pwm_pm_ops, + lcdc_pwm_suspend, lcdc_pwm_resume); + +static int lcdc_pwm_probe(struct platform_device *pdev) +{ + struct atmel_mfd_lcdc *mfd_lcdc; + struct lcdc_pwm *chip; + struct device *dev; + int ret; + + dev = &pdev->dev; + mfd_lcdc = dev_get_drvdata(dev->parent); + + chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + ret = clk_prepare_enable(mfd_lcdc->lcdc_clk); + if (ret) + return ret; + + chip->mfd_lcdc = mfd_lcdc; + chip->chip.ops = &lcdc_pwm_ops; + chip->chip.dev = dev; + chip->chip.base = -1; + chip->chip.npwm = 1; + chip->chip.of_xlate = of_pwm_xlate_with_flags; + chip->chip.of_pwm_n_cells = 3; + + ret = pwmchip_add_with_polarity(&chip->chip, PWM_POLARITY_INVERSED); + if (ret) { + clk_disable_unprepare(mfd_lcdc->lcdc_clk); + return ret; + } + + platform_set_drvdata(pdev, chip); + + return 0; +} + +static int lcdc_pwm_remove(struct platform_device *pdev) +{ + struct lcdc_pwm *chip = platform_get_drvdata(pdev); + int ret; + + ret = pwmchip_remove(&chip->chip); + if (ret) + return ret; + + clk_disable_unprepare(chip->mfd_lcdc->lcdc_clk); + + return 0; +} + +static const struct of_device_id lcdc_pwm_dt_ids[] = { + { .compatible = "atmel,lcdc-pwm" }, + { /* sentinel */ }, +}; + +static struct platform_driver lcdc_pwm_driver = { + .driver = { + .name = "atmel-lcdc-pwm", + .of_match_table = lcdc_pwm_dt_ids, + .pm = &lcdc_pwm_pm_ops, + }, + .probe = lcdc_pwm_probe, + .remove = lcdc_pwm_remove, +}; +module_platform_driver(lcdc_pwm_driver); + +MODULE_ALIAS("platform:pwm-atmel-lcdc"); +MODULE_AUTHOR("Sam Ravnborg sam@ravnborg.org"); +MODULE_DESCRIPTION("Atmel LCDC PWM driver"); +MODULE_LICENSE("GPL v2");