diff options
Diffstat (limited to 'drivers/pwm/pwm-ab8500.c')
| -rw-r--r-- | drivers/pwm/pwm-ab8500.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-ab8500.c b/drivers/pwm/pwm-ab8500.c new file mode 100644 index 000000000..5fa91f4cd --- /dev/null +++ b/drivers/pwm/pwm-ab8500.c @@ -0,0 +1,134 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) ST-Ericsson SA 2010 + * + * Author: Arun R Murthy <arun.murthy@stericsson.com> + */ +#include <linux/err.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/pwm.h> +#include <linux/mfd/abx500.h> +#include <linux/mfd/abx500/ab8500.h> +#include <linux/module.h> + +/* + * PWM Out generators + * Bank: 0x10 + */ +#define AB8500_PWM_OUT_CTRL1_REG 0x60 +#define AB8500_PWM_OUT_CTRL2_REG 0x61 +#define AB8500_PWM_OUT_CTRL7_REG 0x66 + +struct ab8500_pwm_chip { + struct pwm_chip chip; + unsigned int hwid; +}; + +static struct ab8500_pwm_chip *ab8500_pwm_from_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct ab8500_pwm_chip, chip); +} + +static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + int ret; + u8 reg; + unsigned int higher_val, lower_val; + struct ab8500_pwm_chip *ab8500 = ab8500_pwm_from_chip(chip); + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (!state->enabled) { + ret = abx500_mask_and_set_register_interruptible(chip->dev, + AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, + 1 << ab8500->hwid, 0); + + if (ret < 0) + dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return ret; + } + + /* + * get the first 8 bits that are be written to + * AB8500_PWM_OUT_CTRL1_REG[0:7] + */ + lower_val = state->duty_cycle & 0x00FF; + /* + * get bits [9:10] that are to be written to + * AB8500_PWM_OUT_CTRL2_REG[0:1] + */ + higher_val = ((state->duty_cycle & 0x0300) >> 8); + + reg = AB8500_PWM_OUT_CTRL1_REG + (ab8500->hwid * 2); + + ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC, + reg, (u8)lower_val); + if (ret < 0) + return ret; + + ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC, + (reg + 1), (u8)higher_val); + if (ret < 0) + return ret; + + ret = abx500_mask_and_set_register_interruptible(chip->dev, + AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, + 1 << ab8500->hwid, 1 << ab8500->hwid); + if (ret < 0) + dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n", + pwm->label, ret); + + return ret; +} + +static const struct pwm_ops ab8500_pwm_ops = { + .apply = ab8500_pwm_apply, + .owner = THIS_MODULE, +}; + +static int ab8500_pwm_probe(struct platform_device *pdev) +{ + struct ab8500_pwm_chip *ab8500; + int err; + + if (pdev->id < 1 || pdev->id > 31) + return dev_err_probe(&pdev->dev, -EINVAL, "Invalid device id %d\n", pdev->id); + + /* + * Nothing to be done in probe, this is required to get the + * device which is required for ab8500 read and write + */ + ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL); + if (ab8500 == NULL) + return -ENOMEM; + + ab8500->chip.dev = &pdev->dev; + ab8500->chip.ops = &ab8500_pwm_ops; + ab8500->chip.npwm = 1; + ab8500->hwid = pdev->id - 1; + + err = devm_pwmchip_add(&pdev->dev, &ab8500->chip); + if (err < 0) + return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n"); + + dev_dbg(&pdev->dev, "pwm probe successful\n"); + + return 0; +} + +static struct platform_driver ab8500_pwm_driver = { + .driver = { + .name = "ab8500-pwm", + }, + .probe = ab8500_pwm_probe, +}; +module_platform_driver(ab8500_pwm_driver); + +MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>"); +MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver"); +MODULE_ALIAS("platform:ab8500-pwm"); +MODULE_LICENSE("GPL v2"); |