[PATCH V3 22/63] ST SPEAr: Adding support for ST's PWM IP
Viresh Kumar
viresh.kumar at st.com
Mon Dec 20 03:25:42 EST 2010
Signed-off-by: Viresh Kumar <viresh.kumar at st.com>
---
arch/arm/mach-spear3xx/include/mach/generic.h | 1 +
arch/arm/mach-spear3xx/spear320.c | 17 +
arch/arm/mach-spear3xx/spear320_evb.c | 1 +
arch/arm/plat-spear/Kconfig | 7 +
arch/arm/plat-spear/Makefile | 1 +
arch/arm/plat-spear/pwm.c | 484 +++++++++++++++++++++++++
6 files changed, 511 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/plat-spear/pwm.c
diff --git a/arch/arm/mach-spear3xx/include/mach/generic.h b/arch/arm/mach-spear3xx/include/mach/generic.h
index 70f7ee2..447de7e 100644
--- a/arch/arm/mach-spear3xx/include/mach/generic.h
+++ b/arch/arm/mach-spear3xx/include/mach/generic.h
@@ -174,6 +174,7 @@ void __init spear310_init(void);
extern struct amba_device clcd_device;
extern struct platform_device i2c1_device;
extern struct platform_device plgpio_device;
+extern struct platform_device pwm_device;
/* pad mux modes */
extern struct pmx_mode auto_net_smii_mode;
diff --git a/arch/arm/mach-spear3xx/spear320.c b/arch/arm/mach-spear3xx/spear320.c
index bfb21ae..75e7890 100644
--- a/arch/arm/mach-spear3xx/spear320.c
+++ b/arch/arm/mach-spear3xx/spear320.c
@@ -452,6 +452,23 @@ struct platform_device plgpio_device = {
.resource = plgpio_resources,
};
+/* pwm device registeration */
+static struct resource pwm_resources[] = {
+ {
+ .start = SPEAR320_PWM_BASE,
+ .end = SPEAR320_PWM_BASE + SZ_4K - 1,
+ .flags = IORESOURCE_MEM,
+ },
+};
+
+struct platform_device pwm_device = {
+ .name = "pwm",
+ .id = -1,
+ .num_resources = ARRAY_SIZE(pwm_resources),
+ .resource = pwm_resources,
+};
+
+
/* spear3xx shared irq */
struct shirq_dev_config shirq_ras1_config[] = {
{
diff --git a/arch/arm/mach-spear3xx/spear320_evb.c b/arch/arm/mach-spear3xx/spear320_evb.c
index f90a9b8..943eddc 100644
--- a/arch/arm/mach-spear3xx/spear320_evb.c
+++ b/arch/arm/mach-spear3xx/spear320_evb.c
@@ -57,6 +57,7 @@ static struct platform_device *plat_devs[] __initdata = {
/* spear320 specific devices */
&i2c1_device,
&plgpio_device,
+ &pwm_device,
};
static void __init spear320_evb_init(void)
diff --git a/arch/arm/plat-spear/Kconfig b/arch/arm/plat-spear/Kconfig
index 29a25d2..80f402b 100644
--- a/arch/arm/plat-spear/Kconfig
+++ b/arch/arm/plat-spear/Kconfig
@@ -36,4 +36,11 @@ source "arch/arm/mach-spear13xx/Kconfig"
source "arch/arm/mach-spear3xx/Kconfig"
source "arch/arm/mach-spear6xx/Kconfig"
+config SPEAR_PWM
+ tristate "SPEAr Pulse Width Modulator"
+ depends on MACH_SPEAR320
+ default y
+ help
+ Support for ST Microelectronics Pulse Width Modulator present on SPEAr Platform.
+
endif
diff --git a/arch/arm/plat-spear/Makefile b/arch/arm/plat-spear/Makefile
index c31892a..0e29587 100644
--- a/arch/arm/plat-spear/Makefile
+++ b/arch/arm/plat-spear/Makefile
@@ -8,6 +8,7 @@ obj-y := clcd.o clock.o time.o
obj-$(CONFIG_ARCH_SPEAR3XX) += shirq.o padmux.o
obj-$(CONFIG_MACH_SPEAR310) += plgpio.o
obj-$(CONFIG_MACH_SPEAR320) += plgpio.o
+obj-$(CONFIG_SPEAR_PWM) += pwm.o
obj-$(CONFIG_BOARD_SPEAR1300_EVB) += i2c_eval_board.o
obj-$(CONFIG_BOARD_SPEAR300_EVB) += i2c_eval_board.o
diff --git a/arch/arm/plat-spear/pwm.c b/arch/arm/plat-spear/pwm.c
new file mode 100644
index 0000000..307c725
--- /dev/null
+++ b/arch/arm/plat-spear/pwm.c
@@ -0,0 +1,484 @@
+/*
+ * arch/arm/plat-spear/pwm.c
+ *
+ * ST Microelectronics SPEAr Pulse Width Modulator driver
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Viresh Kumar<viresh.kumar at st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+/* PWM registers and bits definitions */
+#define PWMCR 0x00
+#define PWMDCR 0x04
+#define PWMPCR 0x08
+
+#define PWM_EN_MASK 0x1
+#define MIN_PRESCALE 0x00
+#define MAX_PRESCALE 0x3FFF
+#define PRESCALE_SHIFT 2
+#define MIN_DUTY 0x0001
+#define MAX_DUTY 0xFFFF
+#define MAX_PERIOD 0xFFFF
+#define MIN_PERIOD 0x0001
+
+#define PWM_DEVICE_PER_IP 4
+#define PWM_DEVICE_OFFSET 0x10
+
+/* lock for pwm_list */
+static DEFINE_SPINLOCK(list_lock);
+/* list of all pwm ips available in system */
+static LIST_HEAD(pwm_list);
+
+/**
+ * struct pwm_device: struct representing pwm device/channel
+ *
+ * pwmd_id: id of pwm device
+ * pwm: pointer to parent pwm ip
+ * label: used for storing label passed in pwm_request
+ * offset: base address offset from parent pwm mmio_base
+ * busy: represents usage status of a pwm device
+ * lock: lock specific to a pwm device
+ * node: node for adding device to parent pwm's devices list
+ *
+ * Each pwm IP contains four independent pwm device/channels. Some or all of
+ * which may be present in our configuration.
+ */
+struct pwm_device {
+ unsigned pwmd_id;
+ struct pwm *pwm;
+ const char *label;
+ unsigned offset;
+ unsigned busy;
+ spinlock_t lock;
+ struct list_head node;
+};
+
+/**
+ * struct pwm: struct representing pwm ip
+ *
+ * id: id of pwm ip
+ * mmio_base: base address of pwm
+ * clk: pointer to clk structure of pwm ip
+ * clk_enabled: clock enable status
+ * pdev: pointer to pdev structure of pwm
+ * lock: lock specific to current pwm ip
+ * devices: list of devices/childrens of pwm ip
+ * node: node for adding pwm to global list of all pwm ips
+ */
+struct pwm {
+ unsigned id;
+ void __iomem *mmio_base;
+ struct clk *clk;
+ int clk_enabled;
+ struct platform_device *pdev;
+ spinlock_t lock;
+ struct list_head devices;
+ struct list_head node;
+};
+
+/*
+ * period_ns = 10^9 * (PRESCALE + 1) * PV / PWM_CLK_RATE
+ * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
+ *
+ * PV = (PWM_CLK_RATE * period_ns)/ (10^9 * (PRESCALE + 1))
+ * DC = (PWM_CLK_RATE * duty_ns)/ (10^9 * (PRESCALE + 1))
+ */
+int pwm_config(struct pwm_device *pwmd, int duty_ns, int period_ns)
+{
+ u64 val, div, clk_rate;
+ unsigned long prescale = MIN_PRESCALE, pv, dc;
+ int ret = 0;
+
+ if (!pwmd) {
+ pr_err("pwm: config - NULL pwm device pointer\n");
+ return -EFAULT;
+ }
+
+ if (period_ns == 0 || duty_ns > period_ns) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ /* TODO: Need to optimize this loop */
+ while (1) {
+ div = 1000000000;
+ div *= 1 + prescale;
+ clk_rate = clk_get_rate(pwmd->pwm->clk);
+ val = clk_rate * period_ns;
+ pv = div64_u64(val, div);
+ val = clk_rate * duty_ns;
+ dc = div64_u64(val, div);
+
+ if ((pv == 0) || (dc == 0)) {
+ ret = -EINVAL;
+ goto err;
+ }
+ if ((pv > MAX_PERIOD) || (dc > MAX_DUTY)) {
+ prescale++;
+ if (prescale > MAX_PRESCALE) {
+ ret = -EINVAL;
+ goto err;
+ }
+ continue;
+ }
+ if ((pv < MIN_PERIOD) || (dc < MIN_DUTY)) {
+ ret = -EINVAL;
+ goto err;
+ }
+ break;
+ }
+
+ /*
+ * NOTE: the clock to PWM has to be enabled first
+ * before writing to the registers
+ */
+ spin_lock(&pwmd->pwm->lock);
+ ret = clk_enable(pwmd->pwm->clk);
+ if (ret) {
+ spin_unlock(&pwmd->pwm->lock);
+ goto err;
+ }
+
+ spin_lock(&pwmd->lock);
+ writel(prescale << PRESCALE_SHIFT, pwmd->pwm->mmio_base +
+ pwmd->offset + PWMCR);
+ writel(dc, pwmd->pwm->mmio_base + pwmd->offset + PWMDCR);
+ writel(pv, pwmd->pwm->mmio_base + pwmd->offset + PWMPCR);
+ spin_unlock(&pwmd->lock);
+ clk_disable(pwmd->pwm->clk);
+ spin_unlock(&pwmd->pwm->lock);
+
+ return 0;
+err:
+ dev_err(&pwmd->pwm->pdev->dev, "pwm config fail\n");
+ return ret;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwmd)
+{
+ int ret = 0;
+ u32 val = 0;
+
+ if (!pwmd) {
+ pr_err("pwm: enable - NULL pwm device pointer\n");
+ return -EFAULT;
+ }
+
+ spin_lock(&pwmd->pwm->lock);
+ ret = clk_enable(pwmd->pwm->clk);
+ if (!ret)
+ pwmd->pwm->clk_enabled++;
+ else {
+ spin_unlock(&pwmd->pwm->lock);
+ goto err;
+ }
+
+ spin_lock(&pwmd->lock);
+ val = readl(pwmd->pwm->mmio_base + pwmd->offset + PWMCR);
+ writel(val | PWM_EN_MASK, pwmd->pwm->mmio_base + pwmd->offset + PWMCR);
+ spin_unlock(&pwmd->lock);
+ spin_unlock(&pwmd->pwm->lock);
+ return 0;
+err:
+ dev_err(&pwmd->pwm->pdev->dev, "pwm enable fail\n");
+ return ret;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwmd)
+{
+ if (!pwmd) {
+ pr_err("pwm: disable - NULL pwm device pointer\n");
+ return;
+ }
+
+ spin_lock(&pwmd->pwm->lock);
+ spin_lock(&pwmd->lock);
+ writel(0, pwmd->pwm->mmio_base + pwmd->offset + PWMCR);
+ if (pwmd->pwm->clk_enabled) {
+ clk_disable(pwmd->pwm->clk);
+ pwmd->pwm->clk_enabled--;
+ }
+ spin_unlock(&pwmd->lock);
+ spin_unlock(&pwmd->pwm->lock);
+}
+EXPORT_SYMBOL(pwm_disable);
+
+struct pwm_device *pwm_request(int pwmd_id, const char *label)
+{
+ int found = 0;
+ struct pwm *pwm;
+ struct pwm_device *pwmd = NULL;
+
+ spin_lock(&list_lock);
+ list_for_each_entry(pwm, &pwm_list, node) {
+ spin_lock(&pwm->lock);
+ list_for_each_entry(pwmd, &pwm->devices, node) {
+ if (pwmd->pwmd_id == pwmd_id) {
+ found = 1;
+ break;
+ }
+ }
+ spin_unlock(&pwm->lock);
+ if (found)
+ break;
+ }
+ spin_unlock(&list_lock);
+
+ if (found) {
+ spin_lock(&pwmd->lock);
+ if (pwmd->busy == 0) {
+ pwmd->busy++;
+ pwmd->label = label;
+ } else
+ pwmd = ERR_PTR(-EBUSY);
+ spin_unlock(&pwmd->lock);
+ } else
+ pwmd = ERR_PTR(-ENOENT);
+
+ if (IS_ERR(pwmd))
+ pr_err("pwm: request fail\n");
+
+ return pwmd;
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwmd)
+{
+ if (!pwmd) {
+ pr_err("pwm: disable - NULL pwm device pointer\n");
+ return;
+ }
+
+ spin_lock(&pwmd->lock);
+ if (pwmd->busy) {
+ pwmd->busy--;
+ pwmd->label = NULL;
+ } else {
+ spin_unlock(&pwmd->lock);
+ dev_warn(&pwmd->pwm->pdev->dev, "pwm device already freed\n");
+ return;
+ }
+
+ spin_unlock(&pwmd->lock);
+}
+EXPORT_SYMBOL(pwm_free);
+
+/* creates and add pwmd device to parent pwm's devices list */
+static int add_pwm_device(unsigned int pwmd_id, struct pwm *pwm)
+{
+ struct pwm_device *pwmd;
+
+ pwmd = kzalloc(sizeof(*pwmd), GFP_KERNEL);
+ if (!pwmd)
+ return -ENOMEM;
+
+ pwmd->pwm = pwm;
+ pwmd->busy = 0;
+ pwmd->pwmd_id = pwmd_id + pwm->id * PWM_DEVICE_PER_IP;
+ pwmd->offset = pwmd_id * PWM_DEVICE_OFFSET;
+ spin_lock_init(&pwmd->lock);
+
+ spin_lock(&pwm->lock);
+ list_add_tail(&pwmd->node, &pwm->devices);
+ spin_unlock(&pwm->lock);
+
+ return 0;
+}
+
+/* removes all pwmd devices from parent pwm's devices list */
+static void remove_pwm_devices(struct pwm *pwm)
+{
+ struct pwm_device *pwmd;
+
+ spin_lock(&pwm->lock);
+ list_for_each_entry(pwmd, &pwm->devices, node) {
+ list_del(&pwmd->node);
+ kfree(pwmd);
+ }
+ spin_unlock(&pwm->lock);
+}
+
+static int __devinit spear_pwm_probe(struct platform_device *pdev)
+{
+ struct pwm *pwm = NULL;
+ struct resource *res;
+ int ret = 0, pwmd_id = 0;
+
+ pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
+ if (!pwm) {
+ ret = -ENOMEM;
+ dev_dbg(&pdev->dev, "failed to allocate memory\n");
+ goto err;
+ }
+
+ pwm->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(pwm->clk)) {
+ ret = PTR_ERR(pwm->clk);
+ dev_dbg(&pdev->dev, "Error getting clock\n");
+ goto err_free;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -ENODEV;
+ dev_dbg(&pdev->dev, "no memory resource defined\n");
+ goto err_free_clk;
+ }
+
+ if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
+ ret = -EBUSY;
+ dev_dbg(&pdev->dev, "failed to request memory resource\n");
+ goto err_free_clk;
+ }
+
+ pwm->mmio_base = ioremap(res->start, resource_size(res));
+ if (!pwm->mmio_base) {
+ ret = -ENOMEM;
+ dev_dbg(&pdev->dev, "failed to ioremap\n");
+ goto err_free_mem;
+ }
+
+ /* initialize pwm structure */
+ pwm->clk_enabled = 0;
+ pwm->pdev = pdev;
+ /* if pdev->id is -1, only one pwm ip is present */
+ if (pdev->id == -1)
+ pwm->id = 0;
+ else
+ pwm->id = pdev->id;
+
+ spin_lock_init(&pwm->lock);
+ INIT_LIST_HEAD(&pwm->devices);
+ platform_set_drvdata(pdev, pwm);
+
+ /* add pwm to pwm list */
+ spin_lock(&list_lock);
+ list_add_tail(&pwm->node, &pwm_list);
+ spin_unlock(&list_lock);
+
+ /* add pwm devices */
+ for (pwmd_id = 0; pwmd_id < PWM_DEVICE_PER_IP; pwmd_id++) {
+ ret = add_pwm_device(pwmd_id, pwm);
+ if (!ret)
+ continue;
+ dev_err(&pdev->dev, "Add device fail for pwm device id: %d\n",
+ pwmd_id);
+ }
+
+ if (list_empty(&pwm->node))
+ goto err_remove_pwm;
+
+ dev_info(&pdev->dev, "Initialization successful\n");
+ return 0;
+
+err_remove_pwm:
+ spin_lock(&list_lock);
+ list_del(&pwm->node);
+ spin_unlock(&list_lock);
+
+ platform_set_drvdata(pdev, NULL);
+ iounmap(pwm->mmio_base);
+err_free_mem:
+ release_mem_region(res->start, resource_size(res));
+err_free_clk:
+ clk_put(pwm->clk);
+err_free:
+ kfree(pwm);
+err:
+ dev_err(&pdev->dev, "Initialization Fail. Error: %d\n", ret);
+
+ return ret;
+}
+
+static int __devexit spear_pwm_remove(struct platform_device *pdev)
+{
+ struct pwm *pwm;
+ struct resource *res;
+ int ret = 0;
+
+ pwm = platform_get_drvdata(pdev);
+ if (pwm == NULL) {
+ ret = -ENODEV;
+ dev_dbg(&pdev->dev, "Remove: get_drvdata fail\n");
+ goto err;
+ }
+ platform_set_drvdata(pdev, NULL);
+
+ /* remove pwm devices */
+ remove_pwm_devices(pwm);
+
+ /* remove pwm from pwm_list */
+ spin_lock(&list_lock);
+ list_del(&pwm->node);
+ spin_unlock(&list_lock);
+
+ iounmap(pwm->mmio_base);
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -ENODEV;
+ dev_dbg(&pdev->dev, "Remove: get_resource fail\n");
+ goto err;
+ }
+ release_mem_region(res->start, resource_size(res));
+
+ if (pwm->clk_enabled)
+ clk_disable(pwm->clk);
+ clk_put(pwm->clk);
+
+ kfree(pwm);
+ return 0;
+
+err:
+ dev_err(&pdev->dev, "Remove: Fail - %d\n", ret);
+ return ret;
+}
+
+static struct platform_driver spear_pwm_driver = {
+ .driver = {
+ .name = "pwm",
+ .bus = &platform_bus_type,
+ .owner = THIS_MODULE,
+ },
+ .probe = spear_pwm_probe,
+ .remove = __devexit_p(spear_pwm_remove)
+};
+
+static int __init spear_pwm_init(void)
+{
+ int ret = 0;
+
+ ret = platform_driver_register(&spear_pwm_driver);
+ if (ret)
+ pr_err("failed to register spear_pwm_driver\n");
+
+ return ret;
+}
+module_init(spear_pwm_init);
+
+static void __exit spear_pwm_exit(void)
+{
+ platform_driver_unregister(&spear_pwm_driver);
+}
+module_exit(spear_pwm_exit);
+
+MODULE_AUTHOR("Viresh Kumar");
+MODULE_DESCRIPTION("SPEAr PWM Driver");
+MODULE_LICENSE("GPL");
--
1.7.2.2
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