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path: root/drivers/pwm/pwm-imx.c
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Diffstat (limited to 'drivers/pwm/pwm-imx.c')
-rw-r--r--drivers/pwm/pwm-imx.c278
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>");