misc: Add ab8500 pwm driver
This patch adds a Pulse Width Modulation driver for Analog Baseband
Chip AB8500.
Signed-off-by: Arun Murthy <arun.murthy@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/misc/ab8500-pwm.c b/drivers/misc/ab8500-pwm.c
new file mode 100644
index 0000000..54e3d05
--- /dev/null
+++ b/drivers/misc/ab8500-pwm.c
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Author: Arun R Murthy <arun.murthy@stericsson.com>
+ * License terms: GNU General Public License (GPL) version 2
+ */
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/pwm.h>
+#include <linux/mfd/ab8500.h>
+#include <linux/mfd/abx500.h>
+
+/*
+ * PWM Out generators
+ * Bank: 0x10
+ */
+#define AB8500_PWM_OUT_CTRL1_REG 0x60
+#define AB8500_PWM_OUT_CTRL2_REG 0x61
+#define AB8500_PWM_OUT_CTRL7_REG 0x66
+
+/* backlight driver constants */
+#define ENABLE_PWM 1
+#define DISABLE_PWM 0
+
+struct pwm_device {
+ struct device *dev;
+ struct list_head node;
+ const char *label;
+ unsigned int pwm_id;
+};
+
+static LIST_HEAD(pwm_list);
+
+int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
+{
+ int ret = 0;
+ unsigned int higher_val, lower_val;
+ u8 reg;
+
+ /*
+ * get the first 8 bits that are be written to
+ * AB8500_PWM_OUT_CTRL1_REG[0:7]
+ */
+ lower_val = duty_ns & 0x00FF;
+ /*
+ * get bits [9:10] that are to be written to
+ * AB8500_PWM_OUT_CTRL2_REG[0:1]
+ */
+ higher_val = ((duty_ns & 0x0300) >> 8);
+
+ reg = AB8500_PWM_OUT_CTRL1_REG + ((pwm->pwm_id - 1) * 2);
+
+ ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
+ reg, (u8)lower_val);
+ if (ret < 0)
+ return ret;
+ ret = abx500_set_register_interruptible(pwm->dev, AB8500_MISC,
+ (reg + 1), (u8)higher_val);
+
+ return ret;
+}
+EXPORT_SYMBOL(pwm_config);
+
+int pwm_enable(struct pwm_device *pwm)
+{
+ int ret;
+
+ ret = abx500_mask_and_set_register_interruptible(pwm->dev,
+ AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
+ 1 << (pwm->pwm_id-1), ENABLE_PWM);
+ if (ret < 0)
+ dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
+ pwm->label, ret);
+ return ret;
+}
+EXPORT_SYMBOL(pwm_enable);
+
+void pwm_disable(struct pwm_device *pwm)
+{
+ int ret;
+
+ ret = abx500_mask_and_set_register_interruptible(pwm->dev,
+ AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
+ 1 << (pwm->pwm_id-1), DISABLE_PWM);
+ if (ret < 0)
+ dev_err(pwm->dev, "%s: Failed to disable PWM, Error %d\n",
+ pwm->label, ret);
+ return;
+}
+EXPORT_SYMBOL(pwm_disable);
+
+struct pwm_device *pwm_request(int pwm_id, const char *label)
+{
+ struct pwm_device *pwm;
+
+ list_for_each_entry(pwm, &pwm_list, node) {
+ if (pwm->pwm_id == pwm_id) {
+ pwm->label = label;
+ pwm->pwm_id = pwm_id;
+ return pwm;
+ }
+ }
+
+ return ERR_PTR(-ENOENT);
+}
+EXPORT_SYMBOL(pwm_request);
+
+void pwm_free(struct pwm_device *pwm)
+{
+ pwm_disable(pwm);
+}
+EXPORT_SYMBOL(pwm_free);
+
+static int __devinit ab8500_pwm_probe(struct platform_device *pdev)
+{
+ struct pwm_device *pwm;
+ /*
+ * Nothing to be done in probe, this is required to get the
+ * device which is required for ab8500 read and write
+ */
+ pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+ if (pwm == NULL) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+ pwm->dev = &pdev->dev;
+ pwm->pwm_id = pdev->id;
+ list_add_tail(&pwm->node, &pwm_list);
+ platform_set_drvdata(pdev, pwm);
+ dev_dbg(pwm->dev, "pwm probe successful\n");
+ return 0;
+}
+
+static int __devexit ab8500_pwm_remove(struct platform_device *pdev)
+{
+ struct pwm_device *pwm = platform_get_drvdata(pdev);
+ list_del(&pwm->node);
+ dev_dbg(&pdev->dev, "pwm driver removed\n");
+ kfree(pwm);
+ return 0;
+}
+
+static struct platform_driver ab8500_pwm_driver = {
+ .driver = {
+ .name = "ab8500-pwm",
+ .owner = THIS_MODULE,
+ },
+ .probe = ab8500_pwm_probe,
+ .remove = __devexit_p(ab8500_pwm_remove),
+};
+
+static int __init ab8500_pwm_init(void)
+{
+ return platform_driver_register(&ab8500_pwm_driver);
+}
+
+static void __exit ab8500_pwm_exit(void)
+{
+ platform_driver_unregister(&ab8500_pwm_driver);
+}
+
+subsys_initcall(ab8500_pwm_init);
+module_exit(ab8500_pwm_exit);
+MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
+MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
+MODULE_ALIAS("AB8500 PWM driver");
+MODULE_LICENSE("GPL v2");