diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-10 20:15:24 +0900 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-10 20:15:24 +0900 |
commit | 2474542f64432398f503373f53bdf620491bcfa8 (patch) | |
tree | 3c9744b138c2158757530814b35c23eed31cf6ce /drivers/pwm/pwm-imx.c | |
parent | c7a6ced9d8e8411bdafe83998474d185a79badc3 (diff) | |
parent | 85f8879ca4f3d26a7f473522101fb74a79bda3f2 (diff) |
Merge tag 'for-3.7-rc1' of git://gitorious.org/linux-pwm/linux-pwm
Pull pwm changes from Thierry Reding:
"All legacy PWM providers have now been moved to the PWM subsystem.
The plan for 3.8 is to adapt all board files to provide a lookup table
for PWM devices in order to get rid of the global namespace.
Subsequently, users of the legacy pwm_request() and pwm_free()
functions can be migrated to the new pwm_get() and pwm_put()
functions. Once this has been completed, the legacy API and the
compatibility code in the core can be removed.
In addition to the above, these changes also add support for
configuring the polarity of a PWM signal (currently only supported on
ECAP and EHRPWM) and include a much needed rework of the i.MX driver.
Managed functions to obtain and release a PWM device (devm_pwm_get()
and devm_pwm_put()) have been added and the pwm-backlight driver has
been updated to use them. If the PWM subsystem hasn't been enabled,
dummy functions are provided that allow the subsystem to safely
compile out.
Some common checks on input parameters have been moved to the core and
removed from the drivers. Finally, a small fix corrects the
description of the PWM specifier's second cell in the device tree
representation."
* tag 'for-3.7-rc1' of git://gitorious.org/linux-pwm/linux-pwm: (23 commits)
pwm: dt: Fix description of second PWM cell
pwm: Check for negative duty-cycle and period
pwm: Add Ingenic JZ4740 support
MIPS: JZ4740: Export timer API
pwm: Move PUV3 PWM driver to PWM framework
unicore32: pwm: Use managed resource allocations
unicore32: pwm: Remove unnecessary indirection
unicore32: pwm: Use module_platform_driver()
unicore32: pwm: Properly remap memory-mapped registers
pwm-backlight: Use devm_pwm_get() instead of pwm_get()
pwm: Move AB8500 PWM driver to PWM framework
pwm: Fix compilation error when CONFIG_PWM is not defined
pwm: i.MX: fix clock lookup
pwm: i.MX: use per clock unconditionally
pwm: i.MX: add devicetree support
pwm: i.MX: Use module_platform_driver
pwm: i.MX: add functions to enable/disable pwm.
pwm: i.MX: remove unnecessary if in pwm_[en|dis]able
pwm: i.MX: factor out SoC specific functions
pwm: pwm-tiehrpwm: Add support for configuring polarity of PWM
...
Diffstat (limited to 'drivers/pwm/pwm-imx.c')
-rw-r--r-- | drivers/pwm/pwm-imx.c | 262 |
1 files changed, 174 insertions, 88 deletions
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c index 2a0b35333972..8a5d3ae2946a 100644 --- a/drivers/pwm/pwm-imx.c +++ b/drivers/pwm/pwm-imx.c @@ -16,8 +16,7 @@ #include <linux/clk.h> #include <linux/io.h> #include <linux/pwm.h> -#include <mach/hardware.h> - +#include <linux/of_device.h> /* i.MX1 and i.MX21 share the same PWM function block: */ @@ -25,6 +24,7 @@ #define MX1_PWMS 0x04 /* PWM Sample Register */ #define MX1_PWMP 0x08 /* PWM Period Register */ +#define MX1_PWMC_EN (1 << 4) /* i.MX27, i.MX31, i.MX35 share the same PWM function block: */ @@ -40,110 +40,165 @@ #define MX3_PWMCR_EN (1 << 0) struct imx_chip { - struct clk *clk; + struct clk *clk_per; + struct clk *clk_ipg; - int clk_enabled; + int enabled; void __iomem *mmio_base; struct pwm_chip chip; + + int (*config)(struct pwm_chip *chip, + struct pwm_device *pwm, int duty_ns, int period_ns); + void (*set_enable)(struct pwm_chip *chip, bool enable); }; #define to_imx_chip(chip) container_of(chip, struct imx_chip, chip) -static int imx_pwm_config(struct pwm_chip *chip, +static int imx_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, int duty_ns, int period_ns) { struct imx_chip *imx = to_imx_chip(chip); - if (!(cpu_is_mx1() || cpu_is_mx21())) { - unsigned long long c; - unsigned long period_cycles, duty_cycles, prescale; - u32 cr; + /* + * The PWM subsystem allows for exact frequencies. However, + * I cannot connect a scope on my device to the PWM line and + * thus cannot provide the program the PWM controller + * exactly. Instead, I'm relying on the fact that the + * Bootloader (u-boot or WinCE+haret) has programmed the PWM + * function group already. So I'll just modify the PWM sample + * register to follow the ratio of duty_ns vs. period_ns + * accordingly. + * + * This is good enough for programming the brightness of + * the LCD backlight. + * + * The real implementation would divide PERCLK[0] first by + * both the prescaler (/1 .. /128) and then by CLKSEL + * (/2 .. /16). + */ + u32 max = readl(imx->mmio_base + MX1_PWMP); + u32 p = max * duty_ns / period_ns; + writel(max - p, imx->mmio_base + MX1_PWMS); + + return 0; +} + +static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable) +{ + struct imx_chip *imx = to_imx_chip(chip); + u32 val; + + val = readl(imx->mmio_base + MX1_PWMC); - c = clk_get_rate(imx->clk); - c = c * period_ns; - do_div(c, 1000000000); - period_cycles = c; + if (enable) + val |= MX1_PWMC_EN; + else + val &= ~MX1_PWMC_EN; + + writel(val, imx->mmio_base + MX1_PWMC); +} - prescale = period_cycles / 0x10000 + 1; +static int imx_pwm_config_v2(struct pwm_chip *chip, + struct pwm_device *pwm, int duty_ns, int period_ns) +{ + struct imx_chip *imx = to_imx_chip(chip); + unsigned long long c; + unsigned long period_cycles, duty_cycles, prescale; + u32 cr; - period_cycles /= prescale; - c = (unsigned long long)period_cycles * duty_ns; - do_div(c, period_ns); - duty_cycles = c; + c = clk_get_rate(imx->clk_per); + c = c * period_ns; + do_div(c, 1000000000); + period_cycles = c; - /* - * according to imx pwm RM, the real period value should be - * PERIOD value in PWMPR plus 2. - */ - if (period_cycles > 2) - period_cycles -= 2; - else - period_cycles = 0; + prescale = period_cycles / 0x10000 + 1; - writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); - writel(period_cycles, imx->mmio_base + MX3_PWMPR); + period_cycles /= prescale; + c = (unsigned long long)period_cycles * duty_ns; + do_div(c, period_ns); + duty_cycles = c; - cr = MX3_PWMCR_PRESCALER(prescale) | - MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | - MX3_PWMCR_DBGEN | MX3_PWMCR_EN; + /* + * according to imx pwm RM, the real period value should be + * PERIOD value in PWMPR plus 2. + */ + if (period_cycles > 2) + period_cycles -= 2; + else + period_cycles = 0; - if (cpu_is_mx25()) - cr |= MX3_PWMCR_CLKSRC_IPG; - else - cr |= MX3_PWMCR_CLKSRC_IPG_HIGH; + writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); + writel(period_cycles, imx->mmio_base + MX3_PWMPR); - writel(cr, imx->mmio_base + MX3_PWMCR); - } else if (cpu_is_mx1() || cpu_is_mx21()) { - /* The PWM subsystem allows for exact frequencies. However, - * I cannot connect a scope on my device to the PWM line and - * thus cannot provide the program the PWM controller - * exactly. Instead, I'm relying on the fact that the - * Bootloader (u-boot or WinCE+haret) has programmed the PWM - * function group already. So I'll just modify the PWM sample - * register to follow the ratio of duty_ns vs. period_ns - * accordingly. - * - * This is good enough for programming the brightness of - * the LCD backlight. - * - * The real implementation would divide PERCLK[0] first by - * both the prescaler (/1 .. /128) and then by CLKSEL - * (/2 .. /16). - */ - u32 max = readl(imx->mmio_base + MX1_PWMP); - u32 p = max * duty_ns / period_ns; - writel(max - p, imx->mmio_base + MX1_PWMS); - } else { - BUG(); - } + cr = MX3_PWMCR_PRESCALER(prescale) | + MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | + MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH; + + if (imx->enabled) + cr |= MX3_PWMCR_EN; + + writel(cr, imx->mmio_base + MX3_PWMCR); return 0; } +static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable) +{ + struct imx_chip *imx = to_imx_chip(chip); + u32 val; + + val = readl(imx->mmio_base + MX3_PWMCR); + + if (enable) + val |= MX3_PWMCR_EN; + else + val &= ~MX3_PWMCR_EN; + + writel(val, imx->mmio_base + MX3_PWMCR); +} + +static int imx_pwm_config(struct pwm_chip *chip, + struct pwm_device *pwm, int duty_ns, int period_ns) +{ + struct imx_chip *imx = to_imx_chip(chip); + int ret; + + ret = clk_prepare_enable(imx->clk_ipg); + if (ret) + return ret; + + ret = imx->config(chip, pwm, duty_ns, period_ns); + + clk_disable_unprepare(imx->clk_ipg); + + return ret; +} + static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) { struct imx_chip *imx = to_imx_chip(chip); - int rc = 0; + int ret; - if (!imx->clk_enabled) { - rc = clk_prepare_enable(imx->clk); - if (!rc) - imx->clk_enabled = 1; - } - return rc; + ret = clk_prepare_enable(imx->clk_per); + if (ret) + return ret; + + imx->set_enable(chip, true); + + imx->enabled = 1; + + return 0; } static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) { struct imx_chip *imx = to_imx_chip(chip); - writel(0, imx->mmio_base + MX3_PWMCR); + imx->set_enable(chip, false); - if (imx->clk_enabled) { - clk_disable_unprepare(imx->clk); - imx->clk_enabled = 0; - } + clk_disable_unprepare(imx->clk_per); + imx->enabled = 0; } static struct pwm_ops imx_pwm_ops = { @@ -153,30 +208,66 @@ static struct pwm_ops imx_pwm_ops = { .owner = THIS_MODULE, }; +struct imx_pwm_data { + int (*config)(struct pwm_chip *chip, + struct pwm_device *pwm, int duty_ns, int period_ns); + void (*set_enable)(struct pwm_chip *chip, bool enable); +}; + +static struct imx_pwm_data imx_pwm_data_v1 = { + .config = imx_pwm_config_v1, + .set_enable = imx_pwm_set_enable_v1, +}; + +static struct imx_pwm_data imx_pwm_data_v2 = { + .config = imx_pwm_config_v2, + .set_enable = imx_pwm_set_enable_v2, +}; + +static const struct of_device_id imx_pwm_dt_ids[] = { + { .compatible = "fsl,imx1-pwm", .data = &imx_pwm_data_v1, }, + { .compatible = "fsl,imx27-pwm", .data = &imx_pwm_data_v2, }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, imx_pwm_dt_ids); + static int __devinit imx_pwm_probe(struct platform_device *pdev) { + const struct of_device_id *of_id = + of_match_device(imx_pwm_dt_ids, &pdev->dev); + struct imx_pwm_data *data; struct imx_chip *imx; struct resource *r; int ret = 0; + if (!of_id) + return -ENODEV; + imx = devm_kzalloc(&pdev->dev, sizeof(*imx), GFP_KERNEL); if (imx == NULL) { dev_err(&pdev->dev, "failed to allocate memory\n"); return -ENOMEM; } - imx->clk = devm_clk_get(&pdev->dev, "pwm"); + imx->clk_per = devm_clk_get(&pdev->dev, "per"); + if (IS_ERR(imx->clk_per)) { + dev_err(&pdev->dev, "getting per clock failed with %ld\n", + PTR_ERR(imx->clk_per)); + return PTR_ERR(imx->clk_per); + } - if (IS_ERR(imx->clk)) - return PTR_ERR(imx->clk); + imx->clk_ipg = devm_clk_get(&pdev->dev, "ipg"); + if (IS_ERR(imx->clk_ipg)) { + dev_err(&pdev->dev, "getting ipg clock failed with %ld\n", + PTR_ERR(imx->clk_ipg)); + return PTR_ERR(imx->clk_ipg); + } imx->chip.ops = &imx_pwm_ops; imx->chip.dev = &pdev->dev; imx->chip.base = -1; imx->chip.npwm = 1; - imx->clk_enabled = 0; - r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (r == NULL) { dev_err(&pdev->dev, "no memory resource defined\n"); @@ -187,6 +278,10 @@ static int __devinit imx_pwm_probe(struct platform_device *pdev) if (imx->mmio_base == NULL) return -EADDRNOTAVAIL; + data = of_id->data; + imx->config = data->config; + imx->set_enable = data->set_enable; + ret = pwmchip_add(&imx->chip); if (ret < 0) return ret; @@ -208,23 +303,14 @@ static int __devexit imx_pwm_remove(struct platform_device *pdev) static struct platform_driver imx_pwm_driver = { .driver = { - .name = "mxc_pwm", + .name = "imx-pwm", + .of_match_table = of_match_ptr(imx_pwm_dt_ids), }, .probe = imx_pwm_probe, .remove = __devexit_p(imx_pwm_remove), }; -static int __init imx_pwm_init(void) -{ - return platform_driver_register(&imx_pwm_driver); -} -arch_initcall(imx_pwm_init); - -static void __exit imx_pwm_exit(void) -{ - platform_driver_unregister(&imx_pwm_driver); -} -module_exit(imx_pwm_exit); +module_platform_driver(imx_pwm_driver); MODULE_LICENSE("GPL v2"); MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); |