diff options
Diffstat (limited to 'drivers/pwm/pwm-ab8500.c')
| -rw-r--r-- | drivers/pwm/pwm-ab8500.c | 212 |
1 files changed, 144 insertions, 68 deletions
diff --git a/drivers/pwm/pwm-ab8500.c b/drivers/pwm/pwm-ab8500.c index 1d07a6f99375..f000adab85b0 100644 --- a/drivers/pwm/pwm-ab8500.c +++ b/drivers/pwm/pwm-ab8500.c @@ -1,8 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) ST-Ericsson SA 2010 * * Author: Arun R Murthy <arun.murthy@stericsson.com> - * License terms: GNU General Public License (GPL) version 2 + * Datasheet: https://web.archive.org/web/20130614115108/http://www.stericsson.com/developers/CD00291561_UM1031_AB8500_user_manual-rev5_CTDS_public.pdf */ #include <linux/err.h> #include <linux/platform_device.h> @@ -20,117 +21,194 @@ #define AB8500_PWM_OUT_CTRL2_REG 0x61 #define AB8500_PWM_OUT_CTRL7_REG 0x66 -/* backlight driver constants */ -#define ENABLE_PWM 1 -#define DISABLE_PWM 0 +#define AB8500_PWM_CLKRATE 9600000 struct ab8500_pwm_chip { - struct pwm_chip chip; + unsigned int hwid; }; -static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, - int duty_ns, int period_ns) +static struct ab8500_pwm_chip *ab8500_pwm_from_chip(struct pwm_chip *chip) { - int ret = 0; - unsigned int higher_val, lower_val; + return pwmchip_get_drvdata(chip); +} + +static int ab8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + int ret; u8 reg; + u8 higher_val, lower_val; + unsigned int duty_steps, div; + struct ab8500_pwm_chip *ab8500 = ab8500_pwm_from_chip(chip); + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (state->enabled) { + /* + * A time quantum is + * q = (32 - FreqPWMOutx[3:0]) / AB8500_PWM_CLKRATE + * The period is always 1024 q, duty_cycle is between 1q and 1024q. + * + * FreqPWMOutx[3:0] | output frequency | output frequency | 1024q = period + * | (from manual) | (1 / 1024q) | = 1 / freq + * -----------------+------------------+------------------+-------------- + * b0000 | 293 Hz | 292.968750 Hz | 3413333.33 ns + * b0001 | 302 Hz | 302.419355 Hz | 3306666.66 ns + * b0010 | 312 Hz | 312.500000 Hz | 3200000 ns + * b0011 | 323 Hz | 323.275862 Hz | 3093333.33 ns + * b0100 | 334 Hz | 334.821429 Hz | 2986666.66 ns + * b0101 | 347 Hz | 347.222222 Hz | 2880000 ns + * b0110 | 360 Hz | 360.576923 Hz | 2773333.33 ns + * b0111 | 375 Hz | 375.000000 Hz | 2666666.66 ns + * b1000 | 390 Hz | 390.625000 Hz | 2560000 ns + * b1001 | 407 Hz | 407.608696 Hz | 2453333.33 ns + * b1010 | 426 Hz | 426.136364 Hz | 2346666.66 ns + * b1011 | 446 Hz | 446.428571 Hz | 2240000 ns + * b1100 | 468 Hz | 468.750000 Hz | 2133333.33 ns + * b1101 | 493 Hz | 493.421053 Hz | 2026666.66 ns + * b1110 | 520 Hz | 520.833333 Hz | 1920000 ns + * b1111 | 551 Hz | 551.470588 Hz | 1813333.33 ns + * + * + * AB8500_PWM_CLKRATE is a multiple of 1024, so the division by + * 1024 can be done in this factor without loss of precision. + */ + div = min_t(u64, mul_u64_u64_div_u64(state->period, + AB8500_PWM_CLKRATE >> 10, + NSEC_PER_SEC), 32); /* 32 - FreqPWMOutx[3:0] */ + if (div <= 16) + /* requested period < 3413333.33 */ + return -EINVAL; + + duty_steps = max_t(u64, mul_u64_u64_div_u64(state->duty_cycle, + AB8500_PWM_CLKRATE, + (u64)NSEC_PER_SEC * div), 1024); + } + + /* + * The hardware doesn't support duty_steps = 0 explicitly, but emits low + * when disabled. + */ + if (!state->enabled || duty_steps == 0) { + ret = abx500_mask_and_set_register_interruptible(pwmchip_parent(chip), + AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, + 1 << ab8500->hwid, 0); + + if (ret < 0) + dev_err(pwmchip_parent(chip), "%s: Failed to disable PWM, Error %d\n", + pwm->label, ret); + return ret; + } /* - * get the first 8 bits that are be written to + * The lower 8 bits of duty_steps is written to ... * AB8500_PWM_OUT_CTRL1_REG[0:7] */ - lower_val = duty_ns & 0x00FF; + lower_val = (duty_steps - 1) & 0x00ff; /* - * get bits [9:10] that are to be written to - * AB8500_PWM_OUT_CTRL2_REG[0:1] + * The two remaining high bits to + * AB8500_PWM_OUT_CTRL2_REG[0:1]; together with FreqPWMOutx. */ - higher_val = ((duty_ns & 0x0300) >> 8); + higher_val = ((duty_steps - 1) & 0x0300) >> 8 | (32 - div) << 4; - reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2); + reg = AB8500_PWM_OUT_CTRL1_REG + (ab8500->hwid * 2); - ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC, - reg, (u8)lower_val); + ret = abx500_set_register_interruptible(pwmchip_parent(chip), AB8500_MISC, + reg, lower_val); if (ret < 0) return ret; - ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC, - (reg + 1), (u8)higher_val); - return ret; -} - -static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) -{ - int ret; + ret = abx500_set_register_interruptible(pwmchip_parent(chip), AB8500_MISC, + (reg + 1), higher_val); + if (ret < 0) + return ret; - ret = abx500_mask_and_set_register_interruptible(chip->dev, + /* enable */ + ret = abx500_mask_and_set_register_interruptible(pwmchip_parent(chip), AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, - 1 << (chip->base - 1), ENABLE_PWM); + 1 << ab8500->hwid, 1 << ab8500->hwid); if (ret < 0) - dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n", + dev_err(pwmchip_parent(chip), "%s: Failed to enable PWM, Error %d\n", pwm->label, ret); + return ret; } -static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +static int ab8500_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) { + u8 ctrl7, lower_val, higher_val; int ret; + struct ab8500_pwm_chip *ab8500 = ab8500_pwm_from_chip(chip); + unsigned int div, duty_steps; - ret = abx500_mask_and_set_register_interruptible(chip->dev, - AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG, - 1 << (chip->base - 1), DISABLE_PWM); - if (ret < 0) - dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n", - pwm->label, ret); - return; + ret = abx500_get_register_interruptible(pwmchip_parent(chip), AB8500_MISC, + AB8500_PWM_OUT_CTRL7_REG, + &ctrl7); + if (ret) + return ret; + + state->polarity = PWM_POLARITY_NORMAL; + + if (!(ctrl7 & 1 << ab8500->hwid)) { + state->enabled = false; + return 0; + } + + ret = abx500_get_register_interruptible(pwmchip_parent(chip), AB8500_MISC, + AB8500_PWM_OUT_CTRL1_REG + (ab8500->hwid * 2), + &lower_val); + if (ret) + return ret; + + ret = abx500_get_register_interruptible(pwmchip_parent(chip), AB8500_MISC, + AB8500_PWM_OUT_CTRL2_REG + (ab8500->hwid * 2), + &higher_val); + if (ret) + return ret; + + div = 32 - ((higher_val & 0xf0) >> 4); + duty_steps = ((higher_val & 3) << 8 | lower_val) + 1; + + state->period = DIV64_U64_ROUND_UP((u64)div << 10, AB8500_PWM_CLKRATE); + state->duty_cycle = DIV64_U64_ROUND_UP((u64)div * duty_steps, AB8500_PWM_CLKRATE); + + return 0; } static const struct pwm_ops ab8500_pwm_ops = { - .config = ab8500_pwm_config, - .enable = ab8500_pwm_enable, - .disable = ab8500_pwm_disable, - .owner = THIS_MODULE, + .apply = ab8500_pwm_apply, + .get_state = ab8500_pwm_get_state, }; static int ab8500_pwm_probe(struct platform_device *pdev) { + struct pwm_chip *chip; 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) { - dev_err(&pdev->dev, "failed to allocate memory\n"); - return -ENOMEM; - } - - ab8500->chip.dev = &pdev->dev; - ab8500->chip.ops = &ab8500_pwm_ops; - ab8500->chip.base = pdev->id; - ab8500->chip.npwm = 1; + chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*ab8500)); + if (IS_ERR(chip)) + return PTR_ERR(chip); - err = pwmchip_add(&ab8500->chip); - if (err < 0) - return err; + ab8500 = ab8500_pwm_from_chip(chip); - dev_dbg(&pdev->dev, "pwm probe successful\n"); - platform_set_drvdata(pdev, ab8500); + chip->ops = &ab8500_pwm_ops; + ab8500->hwid = pdev->id - 1; - return 0; -} - -static int ab8500_pwm_remove(struct platform_device *pdev) -{ - struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev); - int err; - - err = pwmchip_remove(&ab8500->chip); + err = devm_pwmchip_add(&pdev->dev, chip); if (err < 0) - return err; + return dev_err_probe(&pdev->dev, err, "Failed to add pwm chip\n"); - dev_dbg(&pdev->dev, "pwm driver removed\n"); + dev_dbg(&pdev->dev, "pwm probe successful\n"); return 0; } @@ -138,10 +216,8 @@ static int ab8500_pwm_remove(struct platform_device *pdev) static struct platform_driver ab8500_pwm_driver = { .driver = { .name = "ab8500-pwm", - .owner = THIS_MODULE, }, .probe = ab8500_pwm_probe, - .remove = ab8500_pwm_remove, }; module_platform_driver(ab8500_pwm_driver); |