diff options
Diffstat (limited to 'drivers/pwm/pwm-imx.c')
-rw-r--r-- | drivers/pwm/pwm-imx.c | 278 |
1 files changed, 182 insertions, 96 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; - - c = clk_get_rate(imx->clk); - c = c * period_ns; - do_div(c, 1000000000); - period_cycles = c; - - prescale = period_cycles / 0x10000 + 1; - - period_cycles /= prescale; - c = (unsigned long long)period_cycles * duty_ns; - do_div(c, period_ns); - duty_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; - - writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); - writel(period_cycles, imx->mmio_base + MX3_PWMPR); - - cr = MX3_PWMCR_PRESCALER(prescale) | - MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN | - MX3_PWMCR_DBGEN | MX3_PWMCR_EN; - - if (cpu_is_mx25()) - cr |= MX3_PWMCR_CLKSRC_IPG; - else - cr |= MX3_PWMCR_CLKSRC_IPG_HIGH; - - 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(); - } + /* + * 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); + + if (enable) + val |= MX1_PWMC_EN; + else + val &= ~MX1_PWMC_EN; + + writel(val, imx->mmio_base + MX1_PWMC); +} + +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; + + c = clk_get_rate(imx->clk_per); + c = c * period_ns; + do_div(c, 1000000000); + period_cycles = c; + + prescale = period_cycles / 0x10000 + 1; + + period_cycles /= prescale; + c = (unsigned long long)period_cycles * duty_ns; + do_div(c, period_ns); + duty_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; + + writel(duty_cycles, imx->mmio_base + MX3_PWMSAR); + writel(period_cycles, imx->mmio_base + MX3_PWMPR); + + 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>"); |