[ARM] pxa: Add PXA support for PWM API

Patch mainly from Eric Miao, with minor edits by rmk.

Note: PWM0 and PWM2 share the same register I/O space and clock gating
on pxa{27x, 3xx}, thus PWM2 is treated in the driver as a child PWM of
PWM0. And this is also true for PWM1/3.

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

8 files changed, 382 insertions, 3 deletions

diff --git a/arch/arm/mach-pxa/Kconfig b/arch/arm/mach-pxa/Kconfig
index 5da7a6820492..9c01505b1825 100644
--- a/arch/arm/mach-pxa/Kconfig
+++ b/arch/arm/mach-pxa/Kconfig
@@ -273,4 +273,9 @@ config PXA_SSP
         tristate
         help
           Enable support for PXA2xx SSP ports
+
+config PXA_PWM
+        tristate
+        help
+          Enable support for PXA2xx/PXA3xx PWM controllers
 endif
diff --git a/arch/arm/mach-pxa/Makefile b/arch/arm/mach-pxa/Makefile
index 0e6d05bb81aa..02cbc3cfbe01 100644
--- a/arch/arm/mach-pxa/Makefile
+++ b/arch/arm/mach-pxa/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_CPU_FREQ)		+= cpu-pxa.o
 
 # Generic drivers that other drivers may depend upon
 obj-$(CONFIG_PXA_SSP)           += ssp.o
+obj-$(CONFIG_PXA_PWM)           += pwm.o
 
 # SoC-specific code
 obj-$(CONFIG_PXA25x)            += mfp-pxa2xx.o pxa25x.o
diff --git a/arch/arm/mach-pxa/devices.c b/arch/arm/mach-pxa/devices.c
index d6c05b6eab35..794a1076db73 100644
--- a/arch/arm/mach-pxa/devices.c
+++ b/arch/arm/mach-pxa/devices.c
@@ -280,6 +280,36 @@ struct platform_device pxa_device_rtc = {
 
 #ifdef CONFIG_PXA25x
 
+static struct resource pxa25x_resource_pwm0[] = {
+        [0] = {
+                .start  = 0x40b00000,
+                .end    = 0x40b0000f,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+struct platform_device pxa25x_device_pwm0 = {
+        .name           = "pxa25x-pwm",
+        .id             = 0,
+        .resource       = pxa25x_resource_pwm0,
+        .num_resources  = ARRAY_SIZE(pxa25x_resource_pwm0),
+};
+
+static struct resource pxa25x_resource_pwm1[] = {
+        [0] = {
+                .start  = 0x40c00000,
+                .end    = 0x40c0000f,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+struct platform_device pxa25x_device_pwm1 = {
+        .name           = "pxa25x-pwm",
+        .id             = 1,
+        .resource       = pxa25x_resource_pwm1,
+        .num_resources  = ARRAY_SIZE(pxa25x_resource_pwm1),
+};
+
 static u64 pxa25x_ssp_dma_mask = DMA_BIT_MASK(32);
 
 static struct resource pxa25x_resource_ssp[] = {
@@ -568,6 +598,36 @@ struct platform_device pxa27x_device_ssp3 = {
         .num_resources  = ARRAY_SIZE(pxa27x_resource_ssp3),
 };
 
+static struct resource pxa27x_resource_pwm0[] = {
+        [0] = {
+                .start  = 0x40b00000,
+                .end    = 0x40b0001f,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+struct platform_device pxa27x_device_pwm0 = {
+        .name           = "pxa27x-pwm",
+        .id             = 0,
+        .resource       = pxa27x_resource_pwm0,
+        .num_resources  = ARRAY_SIZE(pxa27x_resource_pwm0),
+};
+
+static struct resource pxa27x_resource_pwm1[] = {
+        [0] = {
+                .start  = 0x40c00000,
+                .end    = 0x40c0001f,
+                .flags  = IORESOURCE_MEM,
+        },
+};
+
+struct platform_device pxa27x_device_pwm1 = {
+        .name           = "pxa27x-pwm",
+        .id             = 1,
+        .resource       = pxa27x_resource_pwm1,
+        .num_resources  = ARRAY_SIZE(pxa27x_resource_pwm1),
+};
+
 static struct resource pxa27x_resource_camera[] = {
         [0] = {
                 .start  = 0x50000000,
diff --git a/arch/arm/mach-pxa/devices.h b/arch/arm/mach-pxa/devices.h
index fcab017f27ee..e620a3373d42 100644
--- a/arch/arm/mach-pxa/devices.h
+++ b/arch/arm/mach-pxa/devices.h
@@ -24,4 +24,9 @@ extern struct platform_device pxa27x_device_ssp2;
 extern struct platform_device pxa27x_device_ssp3;
 extern struct platform_device pxa3xx_device_ssp4;
 
+extern struct platform_device pxa25x_device_pwm0;
+extern struct platform_device pxa25x_device_pwm1;
+extern struct platform_device pxa27x_device_pwm0;
+extern struct platform_device pxa27x_device_pwm1;
+
 void __init pxa_register_device(struct platform_device *dev, void *data);
diff --git a/arch/arm/mach-pxa/pwm.c b/arch/arm/mach-pxa/pwm.c
new file mode 100644
index 000000000000..70fb3ca6a058
--- /dev/null
+++ b/arch/arm/mach-pxa/pwm.c
@@ -0,0 +1,299 @@
+/*
+ * linux/arch/arm/mach-pxa/pwm.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/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+
+#include <asm/div64.h>
+#include <asm/arch/pxa-regs.h>
+
+/* 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 pwm_device {
+        struct list_head        node;
+        struct platform_device *pdev;
+
+        const char      *label;
+        struct clk      *clk;
+        void __iomem    *mmio_base;
+
+        unsigned int    use_count;
+        unsigned int    pwm_id;
+};
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE
+ * duty_ns   = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ */
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+        unsigned long long c;
+        unsigned long period_cycles, prescale, pv, dc;
+
+        if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
+                return -EINVAL;
+
+        c = clk_get_rate(pwm->clk);
+        c = c * period_ns;
+        do_div(c, 1000000000);
+        period_cycles = c;
+
+        if (period_cycles < 0)
+                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
+         */
+        clk_enable(pwm->clk);
+        __raw_writel(prescale, pwm->mmio_base + PWMCR);
+        __raw_writel(dc, pwm->mmio_base + PWMDCR);
+        __raw_writel(pv, pwm->mmio_base + PWMPCR);
+        clk_disable(pwm->clk);
+
+        return 0;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+        return clk_enable(pwm->clk);
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+        clk_disable(pwm->clk);
+}
+EXPORT_SYMBOL(pwm_disable);
+
+static DEFINE_MUTEX(pwm_lock);
+static LIST_HEAD(pwm_list);
+
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+        struct pwm_device *pwm;
+        int found = 0;
+
+        mutex_lock(&pwm_lock);
+
+        list_for_each_entry(pwm, &pwm_list, node) {
+                if (pwm->pwm_id == pwm_id && pwm->use_count == 0) {
+                        pwm->use_count++;
+                        pwm->label = label;
+                        found = 1;
+                        break;
+                }
+        }
+
+        mutex_unlock(&pwm_lock);
+
+        return (found) ? pwm : NULL;
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwm)
+{
+        mutex_lock(&pwm_lock);
+
+        if (pwm->use_count) {
+                pwm->use_count--;
+                pwm->label = NULL;
+        } else
+                pr_warning("PWM device already freed\n");
+
+        mutex_unlock(&pwm_lock);
+}
+EXPORT_SYMBOL(pwm_free);
+
+static inline void __add_pwm(struct pwm_device *pwm)
+{
+        mutex_lock(&pwm_lock);
+        list_add_tail(&pwm->node, &pwm_list);
+        mutex_unlock(&pwm_lock);
+}
+
+static struct pwm_device *pwm_probe(struct platform_device *pdev,
+                unsigned int pwm_id, struct pwm_device *parent_pwm)
+{
+        struct pwm_device *pwm;
+        struct resource *r;
+        int ret = 0;
+
+        pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+        if (pwm == NULL) {
+                dev_err(&pdev->dev, "failed to allocate memory\n");
+                return ERR_PTR(-ENOMEM);
+        }
+
+        pwm->clk = clk_get(&pdev->dev, "PWMCLK");
+        if (IS_ERR(pwm->clk)) {
+                ret = PTR_ERR(pwm->clk);
+                goto err_free;
+        }
+
+        pwm->use_count = 0;
+        pwm->pwm_id = pwm_id;
+        pwm->pdev = pdev;
+
+        if (parent_pwm != NULL) {
+                /* registers for the second PWM has offset of 0x10 */
+                pwm->mmio_base = parent_pwm->mmio_base + 0x10;
+                __add_pwm(pwm);
+                return pwm;
+        }
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (r == NULL) {
+                dev_err(&pdev->dev, "no memory resource defined\n");
+                ret = -ENODEV;
+                goto err_free_clk;
+        }
+
+        r = request_mem_region(r->start, r->end - r->start + 1, pdev->name);
+        if (r == NULL) {
+                dev_err(&pdev->dev, "failed to request memory resource\n");
+                ret = -EBUSY;
+                goto err_free_clk;
+        }
+
+        pwm->mmio_base = ioremap(r->start, r->end - r->start + 1);
+        if (pwm->mmio_base == NULL) {
+                dev_err(&pdev->dev, "failed to ioremap() registers\n");
+                ret = -ENODEV;
+                goto err_free_mem;
+        }
+
+        __add_pwm(pwm);
+        platform_set_drvdata(pdev, pwm);
+        return pwm;
+
+err_free_mem:
+        release_mem_region(r->start, r->end - r->start + 1);
+err_free_clk:
+        clk_put(pwm->clk);
+err_free:
+        kfree(pwm);
+        return ERR_PTR(ret);
+}
+
+static int __devinit pxa25x_pwm_probe(struct platform_device *pdev)
+{
+        struct pwm_device *pwm = pwm_probe(pdev, pdev->id, NULL);
+
+        if (IS_ERR(pwm))
+                return PTR_ERR(pwm);
+
+        return 0;
+}
+
+static int __devinit pxa27x_pwm_probe(struct platform_device *pdev)
+{
+        struct pwm_device *pwm;
+
+        pwm = pwm_probe(pdev, pdev->id * 2, NULL);
+        if (IS_ERR(pwm))
+                return PTR_ERR(pwm);
+
+        pwm = pwm_probe(pdev, pdev->id * 2 + 1, pwm);
+        if (IS_ERR(pwm))
+                return PTR_ERR(pwm);
+
+        return 0;
+}
+
+static int __devexit pwm_remove(struct platform_device *pdev)
+{
+        struct pwm_device *pwm;
+        struct resource *r;
+
+        pwm = platform_get_drvdata(pdev);
+        if (pwm == NULL)
+                return -ENODEV;
+
+        mutex_lock(&pwm_lock);
+        list_del(&pwm->node);
+        mutex_unlock(&pwm_lock);
+
+        iounmap(pwm->mmio_base);
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        release_mem_region(r->start, r->end - r->start + 1);
+
+        clk_put(pwm->clk);
+        kfree(pwm);
+        return 0;
+}
+
+static struct platform_driver pxa25x_pwm_driver = {
+        .driver         = {
+                .name   = "pxa25x-pwm",
+        },
+        .probe          = pxa25x_pwm_probe,
+        .remove         = __devexit_p(pwm_remove),
+};
+
+static struct platform_driver pxa27x_pwm_driver = {
+        .driver         = {
+                .name   = "pxa27x-pwm",
+        },
+        .probe          = pxa27x_pwm_probe,
+        .remove         = __devexit_p(pwm_remove),
+};
+
+static int __init pwm_init(void)
+{
+        int ret = 0;
+
+        ret = platform_driver_register(&pxa25x_pwm_driver);
+        if (ret) {
+                printk(KERN_ERR "failed to register pxa25x_pwm_driver\n");
+                return ret;
+        }
+
+        ret = platform_driver_register(&pxa27x_pwm_driver);
+        if (ret) {
+                printk(KERN_ERR "failed to register pxa27x_pwm_driver\n");
+                return ret;
+        }
+
+        return ret;
+}
+arch_initcall(pwm_init);
+
+static void __exit pwm_exit(void)
+{
+        platform_driver_unregister(&pxa25x_pwm_driver);
+        platform_driver_unregister(&pxa27x_pwm_driver);
+}
+module_exit(pwm_exit);
diff --git a/arch/arm/mach-pxa/pxa25x.c b/arch/arm/mach-pxa/pxa25x.c
index e5b417d14bb0..2bed3f98d41c 100644
--- a/arch/arm/mach-pxa/pxa25x.c
+++ b/arch/arm/mach-pxa/pxa25x.c
@@ -129,12 +129,12 @@ static struct clk pxa25x_clks[] = {
         INIT_CKEN("SSPCLK",  SSP, 3686400, 0, &pxa25x_device_ssp.dev),
         INIT_CKEN("SSPCLK", NSSP, 3686400, 0, &pxa25x_device_nssp.dev),
         INIT_CKEN("SSPCLK", ASSP, 3686400, 0, &pxa25x_device_assp.dev),
+        INIT_CKEN("PWMCLK", PWM0, 3686400, 0, &pxa25x_device_pwm0.dev),
+        INIT_CKEN("PWMCLK", PWM1, 3686400, 0, &pxa25x_device_pwm1.dev),
 
         INIT_CKEN("AC97CLK",     AC97,     24576000, 0, NULL),
 
         /*
-        INIT_CKEN("PWMCLK",  PWM0, 3686400,  0, NULL),
-        INIT_CKEN("PWMCLK",  PWM0, 3686400,  0, NULL),
         INIT_CKEN("I2SCLK",  I2S,  14745600, 0, NULL),
         */
         INIT_CKEN("FICPCLK", FICP, 47923000, 0, NULL),
@@ -269,6 +269,8 @@ static struct platform_device *pxa25x_devices[] __initdata = {
         &pxa25x_device_ssp,
         &pxa25x_device_nssp,
         &pxa25x_device_assp,
+        &pxa25x_device_pwm0,
+        &pxa25x_device_pwm1,
 };
 
 static struct sys_device pxa25x_sysdev[] = {
diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
index 7e945836e129..bc2e80f69673 100644
--- a/arch/arm/mach-pxa/pxa27x.c
+++ b/arch/arm/mach-pxa/pxa27x.c
@@ -157,12 +157,13 @@ static struct clk pxa27x_clks[] = {
         INIT_CKEN("SSPCLK", SSP1, 13000000, 0, &pxa27x_device_ssp1.dev),
         INIT_CKEN("SSPCLK", SSP2, 13000000, 0, &pxa27x_device_ssp2.dev),
         INIT_CKEN("SSPCLK", SSP3, 13000000, 0, &pxa27x_device_ssp3.dev),
+        INIT_CKEN("PWMCLK", PWM0, 13000000, 0, &pxa27x_device_pwm0.dev),
+        INIT_CKEN("PWMCLK", PWM1, 13000000, 0, &pxa27x_device_pwm1.dev),
 
         INIT_CKEN("AC97CLK",     AC97,     24576000, 0, NULL),
         INIT_CKEN("AC97CONFCLK", AC97CONF, 24576000, 0, NULL),
 
         /*
-        INIT_CKEN("PWMCLK",  PWM0, 13000000, 0, NULL),
         INIT_CKEN("MSLCLK",  MSL,  48000000, 0, NULL),
         INIT_CKEN("USIMCLK", USIM, 48000000, 0, NULL),
         INIT_CKEN("MSTKCLK", MEMSTK, 19500000, 0, NULL),
@@ -363,6 +364,8 @@ static struct platform_device *devices[] __initdata = {
         &pxa27x_device_ssp1,
         &pxa27x_device_ssp2,
         &pxa27x_device_ssp3,
+        &pxa27x_device_pwm0,
+        &pxa27x_device_pwm1,
 };
 
 static struct sys_device pxa27x_sysdev[] = {
diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
index 644550bfa330..0f717df1fdb2 100644
--- a/arch/arm/mach-pxa/pxa3xx.c
+++ b/arch/arm/mach-pxa/pxa3xx.c
@@ -239,6 +239,8 @@ static struct clk pxa3xx_clks[] = {
         PXA3xx_CKEN("SSPCLK", SSP2, 13000000, 0, &pxa27x_device_ssp2.dev),
         PXA3xx_CKEN("SSPCLK", SSP3, 13000000, 0, &pxa27x_device_ssp3.dev),
         PXA3xx_CKEN("SSPCLK", SSP4, 13000000, 0, &pxa3xx_device_ssp4.dev),
+        PXA3xx_CKEN("PWMCLK", PWM0, 13000000, 0, &pxa27x_device_pwm0.dev),
+        PXA3xx_CKEN("PWMCLK", PWM1, 13000000, 0, &pxa27x_device_pwm1.dev),
 
         PXA3xx_CKEN("MMCCLK", MMC1, 19500000, 0, &pxa_device_mci.dev),
         PXA3xx_CKEN("MMCCLK", MMC2, 19500000, 0, &pxa3xx_device_mci2.dev),
@@ -530,6 +532,8 @@ static struct platform_device *devices[] __initdata = {
         &pxa27x_device_ssp2,
         &pxa27x_device_ssp3,
         &pxa3xx_device_ssp4,
+        &pxa27x_device_pwm0,
+        &pxa27x_device_pwm1,
 };
 
 static struct sys_device pxa3xx_sysdev[] = {