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authorArun Murthy <arun.murthy@stericsson.com>2010-09-06 12:24:52 +0530
committerSamuel Ortiz <sameo@linux.intel.com>2010-10-29 00:29:21 +0200
commitf0f05b1c751772d19c9c8f36d75e97b1d9687407 (patch)
tree31aa221575b1b05a6f3d63f7185ff01a29541490 /drivers/misc
parent47c1697508f2ec9f6b31ce6c825fe1017871dea6 (diff)
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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>
Diffstat (limited to 'drivers/misc')
-rw-r--r--drivers/misc/Kconfig9
-rw-r--r--drivers/misc/Makefile1
-rw-r--r--drivers/misc/ab8500-pwm.c168
3 files changed, 178 insertions, 0 deletions
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 39a2173b4e6..4d073f1e450 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -62,6 +62,15 @@ config ATMEL_PWM
purposes including software controlled power-efficient backlights
on LCD displays, motor control, and waveform generation.
+config AB8500_PWM
+ bool "AB8500 PWM support"
+ depends on AB8500_CORE
+ select HAVE_PWM
+ help
+ This driver exports functions to enable/disble/config/free Pulse
+ Width Modulation in the Analog Baseband Chip AB8500.
+ It is used by led and backlight driver to control the intensity.
+
config ATMEL_TCLIB
bool "Atmel AT32/AT91 Timer/Counter Library"
depends on (AVR32 || ARCH_AT91)
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 47af4cd08f0..98009cc20cb 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_VMWARE_BALLOON) += vmw_balloon.o
obj-$(CONFIG_ARM_CHARLCD) += arm-charlcd.o
obj-$(CONFIG_PCH_PHUB) += pch_phub.o
obj-y += ti-st/
+obj-$(CONFIG_AB8500_PWM) += ab8500-pwm.o
diff --git a/drivers/misc/ab8500-pwm.c b/drivers/misc/ab8500-pwm.c
new file mode 100644
index 00000000000..54e3d05b63c
--- /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");