diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-30 09:22:37 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-07-30 09:22:37 -0700 |
commit | 9ec97169e7d6afe2f8206d694d1411fb3bb49853 (patch) | |
tree | 9d24c8cd440a312f96b70db5cdaaef1136787003 /drivers/pwm/pwm-pxa.c | |
parent | a410963ba4c0c768302f0298e258b1ee940e8316 (diff) | |
parent | 19891b20e7c275feb92d669f4b1879861f7e8c25 (diff) |
Merge branch 'for-3.6' of git://gitorious.org/linux-pwm/linux-pwm
Pull PWM subsystem from Thierry Reding:
"The new PWM subsystem aims at collecting all implementations of the
legacy PWM API and to eventually replace it completely.
The subsystem has been in development for over half a year now and
many drivers have already been converted. It has been in linux-next
for a couple of weeks and there have been no major issues so I think
it is ready for inclusion in your tree."
Arnd Bergmann <arnd@arndb.de>:
"Very much Ack on the new subsystem. It uses the interface
declarations as the previously separate pwm drivers, so nothing
changes for now in the drivers using it, although it enables us to
change those more easily in the future if we want to.
This work is also one of the missing pieces that are required to
eventually build ARM kernels for multiple platforms, which is
currently prohibited (amongs other things) by the fact that you cannot
have more than one driver exporting the pwm functions."
Tested-and-acked-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Philip, Avinash <avinashphilip@ti.com> # TI's AM33xx platforms
Acked-By: Alexandre Pereira da Silva <aletes.xgr@gmail.com> # LPC32XX
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Sachin Kamat <sachin.kamat@linaro.org>
Fix up trivial conflicts with other cleanups and DT updates.
* 'for-3.6' of git://gitorious.org/linux-pwm/linux-pwm: (36 commits)
pwm: pwm-tiehrpwm: PWM driver support for EHRPWM
pwm: pwm-tiecap: PWM driver support for ECAP APWM
pwm: fix used-uninitialized warning in pwm_get()
pwm: add lpc32xx PWM support
pwm_backlight: pass correct brightness to callback
pwm: Use pr_* functions in pwm-samsung.c file
pwm: Convert pwm-samsung to use devm_* APIs
pwm: Convert pwm-tegra to use devm_clk_get()
pwm: pwm-mxs: Return proper error if pwmchip_remove() fails
pwm: pwm-bfin: Return proper error if pwmchip_remove() fails
pwm: pxa: Propagate pwmchip_remove() error
pwm: Convert pwm-pxa to use devm_* APIs
pwm: Convert pwm-vt8500 to use devm_* APIs
pwm: Convert pwm-imx to use devm_* APIs
pwm: Conflict with legacy PWM API
pwm: pwm-mxs: add pinctrl support
pwm: pwm-mxs: use devm_* managed functions
pwm: pwm-mxs: use global reset function stmp_reset_block
pwm: pwm-mxs: encode soc name in compatible string
pwm: Take over maintainership of the PWM subsystem
...
Diffstat (limited to 'drivers/pwm/pwm-pxa.c')
-rw-r--r-- | drivers/pwm/pwm-pxa.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c new file mode 100644 index 000000000000..bd5867a1c700 --- /dev/null +++ b/drivers/pwm/pwm-pxa.c @@ -0,0 +1,218 @@ +/* + * drivers/pwm/pwm-pxa.c + * + * simple driver for PWM (Pulse Width Modulator) controller + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 2008-02-13 initial version + * eric miao <eric.miao@marvell.com> + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/pwm.h> + +#include <asm/div64.h> + +#define HAS_SECONDARY_PWM 0x10 +#define PWM_ID_BASE(d) ((d) & 0xf) + +static const struct platform_device_id pwm_id_table[] = { + /* PWM has_secondary_pwm? */ + { "pxa25x-pwm", 0 }, + { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM }, + { "pxa168-pwm", 1 }, + { "pxa910-pwm", 1 }, + { }, +}; +MODULE_DEVICE_TABLE(platform, pwm_id_table); + +/* PWM registers and bits definitions */ +#define PWMCR (0x00) +#define PWMDCR (0x04) +#define PWMPCR (0x08) + +#define PWMCR_SD (1 << 6) +#define PWMDCR_FD (1 << 10) + +struct pxa_pwm_chip { + struct pwm_chip chip; + struct device *dev; + + struct clk *clk; + int clk_enabled; + void __iomem *mmio_base; +}; + +static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct pxa_pwm_chip, chip); +} + +/* + * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE + * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE + */ +static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); + unsigned long long c; + unsigned long period_cycles, prescale, pv, dc; + unsigned long offset; + int rc; + + if (period_ns == 0 || duty_ns > period_ns) + return -EINVAL; + + offset = pwm->hwpwm ? 0x10 : 0; + + c = clk_get_rate(pc->clk); + c = c * period_ns; + do_div(c, 1000000000); + period_cycles = c; + + if (period_cycles < 1) + period_cycles = 1; + prescale = (period_cycles - 1) / 1024; + pv = period_cycles / (prescale + 1) - 1; + + if (prescale > 63) + return -EINVAL; + + if (duty_ns == period_ns) + dc = PWMDCR_FD; + else + dc = (pv + 1) * duty_ns / period_ns; + + /* NOTE: the clock to PWM has to be enabled first + * before writing to the registers + */ + rc = clk_prepare_enable(pc->clk); + if (rc < 0) + return rc; + + writel(prescale, pc->mmio_base + offset + PWMCR); + writel(dc, pc->mmio_base + offset + PWMDCR); + writel(pv, pc->mmio_base + offset + PWMPCR); + + clk_disable_unprepare(pc->clk); + return 0; +} + +static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); + int rc = 0; + + if (!pc->clk_enabled) { + rc = clk_prepare_enable(pc->clk); + if (!rc) + pc->clk_enabled++; + } + return rc; +} + +static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); + + if (pc->clk_enabled) { + clk_disable_unprepare(pc->clk); + pc->clk_enabled--; + } +} + +static struct pwm_ops pxa_pwm_ops = { + .config = pxa_pwm_config, + .enable = pxa_pwm_enable, + .disable = pxa_pwm_disable, + .owner = THIS_MODULE, +}; + +static int __devinit pwm_probe(struct platform_device *pdev) +{ + const struct platform_device_id *id = platform_get_device_id(pdev); + struct pxa_pwm_chip *pwm; + struct resource *r; + int ret = 0; + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (pwm == NULL) { + dev_err(&pdev->dev, "failed to allocate memory\n"); + return -ENOMEM; + } + + pwm->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(pwm->clk)) + return PTR_ERR(pwm->clk); + + pwm->clk_enabled = 0; + + pwm->chip.dev = &pdev->dev; + pwm->chip.ops = &pxa_pwm_ops; + pwm->chip.base = -1; + pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + dev_err(&pdev->dev, "no memory resource defined\n"); + return -ENODEV; + } + + pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r); + if (pwm->mmio_base == NULL) + return -EADDRNOTAVAIL; + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); + return ret; + } + + platform_set_drvdata(pdev, pwm); + return 0; +} + +static int __devexit pwm_remove(struct platform_device *pdev) +{ + struct pxa_pwm_chip *chip; + + chip = platform_get_drvdata(pdev); + if (chip == NULL) + return -ENODEV; + + return pwmchip_remove(&chip->chip); +} + +static struct platform_driver pwm_driver = { + .driver = { + .name = "pxa25x-pwm", + .owner = THIS_MODULE, + }, + .probe = pwm_probe, + .remove = __devexit_p(pwm_remove), + .id_table = pwm_id_table, +}; + +static int __init pwm_init(void) +{ + return platform_driver_register(&pwm_driver); +} +arch_initcall(pwm_init); + +static void __exit pwm_exit(void) +{ + platform_driver_unregister(&pwm_driver); +} +module_exit(pwm_exit); + +MODULE_LICENSE("GPL v2"); |