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authorMark Brown <broonie@opensource.wolfsonmicro.com>2009-09-22 08:47:11 -0700
committerLiam Girdwood <lrg@slimlogic.co.uk>2009-12-17 10:27:22 +0000
commite24a04c44cf312e88b50006a91ad7ffc1c0d97a5 (patch)
treea8f4b9c2f5caaed9646a1118b8d9cd84de134439 /drivers/regulator
parent27f37e4bfed803be338dcc78845d4a67eefb40a0 (diff)
regulator: Implement WM831x BuckWise DC-DC convertor DVS support
The BuckWise DC-DC convertors in WM831x devices support switching to a second output voltage using the logic level on one of the device pins. This is intended to allow rapid voltage switching for uses like cpufreq, replacing the I2C or SPI write used to configure the voltage of the regulator with a much faster GPIO status change. This is implemented by keeping the DVS voltage configured as the maximum voltage permitted for the regulator. If a request is made for the maximum voltage then the GPIO is used to switch to the DVS voltage, otherwise the normal ON voltage is updated and used. This follows the idiom used by most cpufreq drivers, which drop the minimum voltage as the core frequency is dropped but use a constant maximum - raising the voltage should normally be fast, but lowering it may be slower. Configuration of the DVS MFP on the device should be done externally, for example via OTP. Support is present in the hardware for monitoring the status of the transition using a second GPIO. This is not currently implemented but platform data is provided for it - the driver currently assumes that the device will be configured to transition immediately - but platform data is provided to reduce merge issues once it is. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Diffstat (limited to 'drivers/regulator')
-rw-r--r--drivers/regulator/wm831x-dcdc.c207
1 files changed, 189 insertions, 18 deletions
diff --git a/drivers/regulator/wm831x-dcdc.c b/drivers/regulator/wm831x-dcdc.c
index 2eefc1a0cf0..0a6577577e8 100644
--- a/drivers/regulator/wm831x-dcdc.c
+++ b/drivers/regulator/wm831x-dcdc.c
@@ -19,6 +19,8 @@
#include <linux/i2c.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/gpio.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/regulator.h>
@@ -39,6 +41,7 @@
#define WM831X_DCDC_CONTROL_2 1
#define WM831X_DCDC_ON_CONFIG 2
#define WM831X_DCDC_SLEEP_CONTROL 3
+#define WM831X_DCDC_DVS_CONTROL 4
/*
* Shared
@@ -50,6 +53,10 @@ struct wm831x_dcdc {
int base;
struct wm831x *wm831x;
struct regulator_dev *regulator;
+ int dvs_gpio;
+ int dvs_gpio_state;
+ int on_vsel;
+ int dvs_vsel;
};
static int wm831x_dcdc_is_enabled(struct regulator_dev *rdev)
@@ -240,11 +247,9 @@ static int wm831x_buckv_list_voltage(struct regulator_dev *rdev,
return -EINVAL;
}
-static int wm831x_buckv_set_voltage_int(struct regulator_dev *rdev, int reg,
- int min_uV, int max_uV)
+static int wm831x_buckv_select_min_voltage(struct regulator_dev *rdev,
+ int min_uV, int max_uV)
{
- struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
- struct wm831x *wm831x = dcdc->wm831x;
u16 vsel;
if (min_uV < 600000)
@@ -257,39 +262,126 @@ static int wm831x_buckv_set_voltage_int(struct regulator_dev *rdev, int reg,
if (wm831x_buckv_list_voltage(rdev, vsel) > max_uV)
return -EINVAL;
- return wm831x_set_bits(wm831x, reg, WM831X_DC1_ON_VSEL_MASK, vsel);
+ return vsel;
+}
+
+static int wm831x_buckv_select_max_voltage(struct regulator_dev *rdev,
+ int min_uV, int max_uV)
+{
+ u16 vsel;
+
+ if (max_uV < 600000 || max_uV > 1800000)
+ return -EINVAL;
+
+ vsel = ((max_uV - 600000) / 12500) + 8;
+
+ if (wm831x_buckv_list_voltage(rdev, vsel) < min_uV ||
+ wm831x_buckv_list_voltage(rdev, vsel) < max_uV)
+ return -EINVAL;
+
+ return vsel;
+}
+
+static int wm831x_buckv_set_dvs(struct regulator_dev *rdev, int state)
+{
+ struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
+
+ if (state == dcdc->dvs_gpio_state)
+ return 0;
+
+ dcdc->dvs_gpio_state = state;
+ gpio_set_value(dcdc->dvs_gpio, state);
+
+ /* Should wait for DVS state change to be asserted if we have
+ * a GPIO for it, for now assume the device is configured
+ * for the fastest possible transition.
+ */
+
+ return 0;
}
static int wm831x_buckv_set_voltage(struct regulator_dev *rdev,
- int min_uV, int max_uV)
+ int min_uV, int max_uV)
{
struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
- u16 reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
+ struct wm831x *wm831x = dcdc->wm831x;
+ int on_reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
+ int dvs_reg = dcdc->base + WM831X_DCDC_DVS_CONTROL;
+ int vsel, ret;
+
+ vsel = wm831x_buckv_select_min_voltage(rdev, min_uV, max_uV);
+ if (vsel < 0)
+ return vsel;
+
+ /* If this value is already set then do a GPIO update if we can */
+ if (dcdc->dvs_gpio && dcdc->on_vsel == vsel)
+ return wm831x_buckv_set_dvs(rdev, 0);
+
+ if (dcdc->dvs_gpio && dcdc->dvs_vsel == vsel)
+ return wm831x_buckv_set_dvs(rdev, 1);
+
+ /* Always set the ON status to the minimum voltage */
+ ret = wm831x_set_bits(wm831x, on_reg, WM831X_DC1_ON_VSEL_MASK, vsel);
+ if (ret < 0)
+ return ret;
+ dcdc->on_vsel = vsel;
+
+ if (!dcdc->dvs_gpio)
+ return ret;
+
+ /* Kick the voltage transition now */
+ ret = wm831x_buckv_set_dvs(rdev, 0);
+ if (ret < 0)
+ return ret;
+
+ /* Set the high voltage as the DVS voltage. This is optimised
+ * for CPUfreq usage, most processors will keep the maximum
+ * voltage constant and lower the minimum with the frequency. */
+ vsel = wm831x_buckv_select_max_voltage(rdev, min_uV, max_uV);
+ if (vsel < 0) {
+ /* This should never happen - at worst the same vsel
+ * should be chosen */
+ WARN_ON(vsel < 0);
+ return 0;
+ }
+
+ /* Don't bother if it's the same VSEL we're already using */
+ if (vsel == dcdc->on_vsel)
+ return 0;
- return wm831x_buckv_set_voltage_int(rdev, reg, min_uV, max_uV);
+ ret = wm831x_set_bits(wm831x, dvs_reg, WM831X_DC1_DVS_VSEL_MASK, vsel);
+ if (ret == 0)
+ dcdc->dvs_vsel = vsel;
+ else
+ dev_warn(wm831x->dev, "Failed to set DCDC DVS VSEL: %d\n",
+ ret);
+
+ return 0;
}
static int wm831x_buckv_set_suspend_voltage(struct regulator_dev *rdev,
- int uV)
+ int uV)
{
struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
+ struct wm831x *wm831x = dcdc->wm831x;
u16 reg = dcdc->base + WM831X_DCDC_SLEEP_CONTROL;
+ int vsel;
+
+ vsel = wm831x_buckv_select_min_voltage(rdev, uV, uV);
+ if (vsel < 0)
+ return vsel;
- return wm831x_buckv_set_voltage_int(rdev, reg, uV, uV);
+ return wm831x_set_bits(wm831x, reg, WM831X_DC1_SLP_VSEL_MASK, vsel);
}
static int wm831x_buckv_get_voltage(struct regulator_dev *rdev)
{
struct wm831x_dcdc *dcdc = rdev_get_drvdata(rdev);
- struct wm831x *wm831x = dcdc->wm831x;
- u16 reg = dcdc->base + WM831X_DCDC_ON_CONFIG;
- int val;
- val = wm831x_reg_read(wm831x, reg);
- if (val < 0)
- return val;
-
- return wm831x_buckv_list_voltage(rdev, val & WM831X_DC1_ON_VSEL_MASK);
+ if (dcdc->dvs_gpio && dcdc->dvs_gpio_state)
+ return wm831x_buckv_list_voltage(rdev, dcdc->dvs_vsel);
+ else
+ return wm831x_buckv_list_voltage(rdev, dcdc->on_vsel);
}
/* Current limit options */
@@ -346,6 +438,64 @@ static struct regulator_ops wm831x_buckv_ops = {
.set_suspend_mode = wm831x_dcdc_set_suspend_mode,
};
+/*
+ * Set up DVS control. We just log errors since we can still run
+ * (with reduced performance) if we fail.
+ */
+static __devinit void wm831x_buckv_dvs_init(struct wm831x_dcdc *dcdc,
+ struct wm831x_buckv_pdata *pdata)
+{
+ struct wm831x *wm831x = dcdc->wm831x;
+ int ret;
+ u16 ctrl;
+
+ if (!pdata || !pdata->dvs_gpio)
+ return;
+
+ switch (pdata->dvs_control_src) {
+ case 1:
+ ctrl = 2 << WM831X_DC1_DVS_SRC_SHIFT;
+ break;
+ case 2:
+ ctrl = 3 << WM831X_DC1_DVS_SRC_SHIFT;
+ break;
+ default:
+ dev_err(wm831x->dev, "Invalid DVS control source %d for %s\n",
+ pdata->dvs_control_src, dcdc->name);
+ return;
+ }
+
+ ret = wm831x_set_bits(wm831x, dcdc->base + WM831X_DCDC_DVS_CONTROL,
+ WM831X_DC1_DVS_SRC_MASK, ctrl);
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to set %s DVS source: %d\n",
+ dcdc->name, ret);
+ return;
+ }
+
+ ret = gpio_request(pdata->dvs_gpio, "DCDC DVS");
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to get %s DVS GPIO: %d\n",
+ dcdc->name, ret);
+ return;
+ }
+
+ /* gpiolib won't let us read the GPIO status so pick the higher
+ * of the two existing voltages so we take it as platform data.
+ */
+ dcdc->dvs_gpio_state = pdata->dvs_init_state;
+
+ ret = gpio_direction_output(pdata->dvs_gpio, dcdc->dvs_gpio_state);
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to enable %s DVS GPIO: %d\n",
+ dcdc->name, ret);
+ gpio_free(pdata->dvs_gpio);
+ return;
+ }
+
+ dcdc->dvs_gpio = pdata->dvs_gpio;
+}
+
static __devinit int wm831x_buckv_probe(struct platform_device *pdev)
{
struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
@@ -384,6 +534,23 @@ static __devinit int wm831x_buckv_probe(struct platform_device *pdev)
dcdc->desc.ops = &wm831x_buckv_ops;
dcdc->desc.owner = THIS_MODULE;
+ ret = wm831x_reg_read(wm831x, dcdc->base + WM831X_DCDC_ON_CONFIG);
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to read ON VSEL: %d\n", ret);
+ goto err;
+ }
+ dcdc->on_vsel = ret & WM831X_DC1_ON_VSEL_MASK;
+
+ ret = wm831x_reg_read(wm831x, dcdc->base + WM831X_DCDC_ON_CONFIG);
+ if (ret < 0) {
+ dev_err(wm831x->dev, "Failed to read DVS VSEL: %d\n", ret);
+ goto err;
+ }
+ dcdc->dvs_vsel = ret & WM831X_DC1_DVS_VSEL_MASK;
+
+ if (pdata->dcdc[id])
+ wm831x_buckv_dvs_init(dcdc, pdata->dcdc[id]->driver_data);
+
dcdc->regulator = regulator_register(&dcdc->desc, &pdev->dev,
pdata->dcdc[id], dcdc);
if (IS_ERR(dcdc->regulator)) {
@@ -422,6 +589,8 @@ err_uv:
err_regulator:
regulator_unregister(dcdc->regulator);
err:
+ if (dcdc->dvs_gpio)
+ gpio_free(dcdc->dvs_gpio);
kfree(dcdc);
return ret;
}
@@ -434,6 +603,8 @@ static __devexit int wm831x_buckv_remove(struct platform_device *pdev)
wm831x_free_irq(wm831x, platform_get_irq_byname(pdev, "HC"), dcdc);
wm831x_free_irq(wm831x, platform_get_irq_byname(pdev, "UV"), dcdc);
regulator_unregister(dcdc->regulator);
+ if (dcdc->dvs_gpio)
+ gpio_free(dcdc->dvs_gpio);
kfree(dcdc);
return 0;