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3eb05225ee
A new driver has been added to support the PWM mode of the timer counter blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained suspend and resume functionality. User drivers can now query the core for whether access to a PWM device will sleep (if the PWM chip is on a slow bus such as I2C or SPI). The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state in addition to the FB layer's blanking states. To round things off, a few fixes and cleanups are also included. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIcBAABAgAGBQJRKxfbAAoJEN0jrNd/PrOhcwEP/0plVf30QDMhcan1GR3l+jmK 3Q/cCNIWEZ75mRu+FtVYKUOduxkCOHR6LM4C2ScGnnpsS/X5oitc45FrblIwQaEI UeWVxDqI+pEp+rCdYVCND4lih60FJU0Cct0zZL2db4D4idF+8FRChhzwzSXhajnj ZZqz782Y2ig3YTLHtVGT1pp61DKxdu1Gz4U+fxo4G1/fnkquCYDzbCQovcmPSnnF gYB8hfxgT9JIt2cHrK6eKCHBF/4GToU+x5zDV2Ub15C2K/UQ+qgw82yl8MNd/ZS5 rFA06iW3icnJRRc8u6hu9WVjNVNTBrUqUlFhctNB01d5jF4R6uR6aEvovT9xe8NW Wa5v5WrjnL6SWpZVwb/3kwwJmkeU9zKESQt5KUw3VKnT8yr2BfxcH1gJIiuW6wK7 uYqknAvt2rwMEGzaKZJmQH682wNMxpJirs8hG9VjJc/v7AOnk6586HbRupAq8wWZ qK4n1Fto9RCg+b6e/hDId7+mN1GEcA5B8BOotPQ6ud+cinDZBKSbCSHhQG2LQ++F m81BbL82H2R2ICRoYNA74/bKq5OVOFFqHLHg5bUrG7ikdNbYOTK/4dF9qSS7DnT3 Bi6WnKpOtfpWbHBnDunP2vBFo3f+gXmbLJdgarxk7mneV8wp0GY6TYI1awWn0hI9 82JP3yiK5kW2JZv92o0H =Fcxi -----END PGP SIGNATURE----- Merge tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm Pull PWM changes from Thierry Reding: "A new driver has been added to support the PWM mode of the timer counter blocks found on Atmel AT91 SoCs. The VT8500 driver now supports changing the PWM signal polarity and the TI drivers (EHRPWM and ECAP) gained suspend and resume functionality. User drivers can now query the core for whether access to a PWM device will sleep (if the PWM chip is on a slow bus such as I2C or SPI). The pwm-backlight driver now handles the backlight BL_CORE_FBBLANK state in addition to the FB layer's blanking states. To round things off, a few fixes and cleanups are also included" * tag 'for-3.9-rc1' of git://gitorious.org/linux-pwm/linux-pwm: pwm: twl: Use to_twl() instead of container_of() pwm: tegra: assume CONFIG_OF pwm_backlight: Validate dft_brightness in main probe function pwm: Export pwm_{set,get}_chip_data() pwm: Make Kconfig entries more consistent pwm: Add can_sleep property to drivers pwm: Add pwm_can_sleep() as exported API to users pwm-backlight: handle BL_CORE_FBBLANK state pwm: pwm-tiecap: Low power sleep support pwm: pwm-tiehrpwm: Low power sleep support pwm: pwm-tiehrpwm: Update the clock handling of pwm-tiehrpwm driver pwm: vt8500: Add polarity support pwm: vt8500: Register write busy test performed incorrectly pwm: atmel: add Timer Counter Block PWM driver
258 lines
6.0 KiB
C
258 lines
6.0 KiB
C
/*
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* drivers/pwm/pwm-tegra.c
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*
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* Tegra pulse-width-modulation controller driver
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*
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* Copyright (c) 2010, NVIDIA Corporation.
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* Based on arch/arm/plat-mxc/pwm.c by Sascha Hauer <s.hauer@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/pwm.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#define PWM_ENABLE (1 << 31)
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#define PWM_DUTY_WIDTH 8
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#define PWM_DUTY_SHIFT 16
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#define PWM_SCALE_WIDTH 13
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#define PWM_SCALE_SHIFT 0
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#define NUM_PWM 4
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struct tegra_pwm_chip {
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struct pwm_chip chip;
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struct device *dev;
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struct clk *clk;
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void __iomem *mmio_base;
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};
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static inline struct tegra_pwm_chip *to_tegra_pwm_chip(struct pwm_chip *chip)
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{
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return container_of(chip, struct tegra_pwm_chip, chip);
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}
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static inline u32 pwm_readl(struct tegra_pwm_chip *chip, unsigned int num)
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{
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return readl(chip->mmio_base + (num << 4));
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}
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static inline void pwm_writel(struct tegra_pwm_chip *chip, unsigned int num,
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unsigned long val)
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{
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writel(val, chip->mmio_base + (num << 4));
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}
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static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
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unsigned long long c;
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unsigned long rate, hz;
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u32 val = 0;
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int err;
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/*
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* Convert from duty_ns / period_ns to a fixed number of duty ticks
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* per (1 << PWM_DUTY_WIDTH) cycles and make sure to round to the
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* nearest integer during division.
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*/
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c = duty_ns * ((1 << PWM_DUTY_WIDTH) - 1) + period_ns / 2;
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do_div(c, period_ns);
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val = (u32)c << PWM_DUTY_SHIFT;
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/*
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* Compute the prescaler value for which (1 << PWM_DUTY_WIDTH)
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* cycles at the PWM clock rate will take period_ns nanoseconds.
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*/
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rate = clk_get_rate(pc->clk) >> PWM_DUTY_WIDTH;
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hz = 1000000000ul / period_ns;
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rate = (rate + (hz / 2)) / hz;
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/*
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* Since the actual PWM divider is the register's frequency divider
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* field minus 1, we need to decrement to get the correct value to
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* write to the register.
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*/
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if (rate > 0)
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rate--;
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/*
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* Make sure that the rate will fit in the register's frequency
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* divider field.
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*/
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if (rate >> PWM_SCALE_WIDTH)
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return -EINVAL;
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val |= rate << PWM_SCALE_SHIFT;
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/*
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* If the PWM channel is disabled, make sure to turn on the clock
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* before writing the register. Otherwise, keep it enabled.
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*/
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if (!test_bit(PWMF_ENABLED, &pwm->flags)) {
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err = clk_prepare_enable(pc->clk);
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if (err < 0)
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return err;
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} else
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val |= PWM_ENABLE;
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pwm_writel(pc, pwm->hwpwm, val);
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/*
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* If the PWM is not enabled, turn the clock off again to save power.
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*/
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if (!test_bit(PWMF_ENABLED, &pwm->flags))
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clk_disable_unprepare(pc->clk);
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return 0;
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}
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static int tegra_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
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int rc = 0;
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u32 val;
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rc = clk_prepare_enable(pc->clk);
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if (rc < 0)
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return rc;
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val = pwm_readl(pc, pwm->hwpwm);
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val |= PWM_ENABLE;
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pwm_writel(pc, pwm->hwpwm, val);
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return 0;
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}
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static void tegra_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct tegra_pwm_chip *pc = to_tegra_pwm_chip(chip);
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u32 val;
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val = pwm_readl(pc, pwm->hwpwm);
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val &= ~PWM_ENABLE;
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pwm_writel(pc, pwm->hwpwm, val);
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clk_disable_unprepare(pc->clk);
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}
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static const struct pwm_ops tegra_pwm_ops = {
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.config = tegra_pwm_config,
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.enable = tegra_pwm_enable,
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.disable = tegra_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int tegra_pwm_probe(struct platform_device *pdev)
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{
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struct tegra_pwm_chip *pwm;
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struct resource *r;
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int ret;
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pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
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if (!pwm) {
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dev_err(&pdev->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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pwm->dev = &pdev->dev;
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r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!r) {
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dev_err(&pdev->dev, "no memory resources defined\n");
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return -ENODEV;
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}
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pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r);
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if (IS_ERR(pwm->mmio_base))
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return PTR_ERR(pwm->mmio_base);
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platform_set_drvdata(pdev, pwm);
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pwm->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(pwm->clk))
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return PTR_ERR(pwm->clk);
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pwm->chip.dev = &pdev->dev;
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pwm->chip.ops = &tegra_pwm_ops;
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pwm->chip.base = -1;
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pwm->chip.npwm = NUM_PWM;
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ret = pwmchip_add(&pwm->chip);
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if (ret < 0) {
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dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
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return ret;
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}
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return 0;
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}
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static int tegra_pwm_remove(struct platform_device *pdev)
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{
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struct tegra_pwm_chip *pc = platform_get_drvdata(pdev);
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int i;
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if (WARN_ON(!pc))
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return -ENODEV;
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for (i = 0; i < NUM_PWM; i++) {
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struct pwm_device *pwm = &pc->chip.pwms[i];
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if (!test_bit(PWMF_ENABLED, &pwm->flags))
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if (clk_prepare_enable(pc->clk) < 0)
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continue;
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pwm_writel(pc, i, 0);
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clk_disable_unprepare(pc->clk);
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}
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return pwmchip_remove(&pc->chip);
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}
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static struct of_device_id tegra_pwm_of_match[] = {
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{ .compatible = "nvidia,tegra20-pwm" },
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{ .compatible = "nvidia,tegra30-pwm" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, tegra_pwm_of_match);
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static struct platform_driver tegra_pwm_driver = {
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.driver = {
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.name = "tegra-pwm",
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.of_match_table = tegra_pwm_of_match,
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},
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.probe = tegra_pwm_probe,
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.remove = tegra_pwm_remove,
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};
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module_platform_driver(tegra_pwm_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("NVIDIA Corporation");
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MODULE_ALIAS("platform:tegra-pwm");
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