Hi.
On 05/25/2012 12:25 PM, Eduardo Valentin wrote:
> In the System Control Module, OMAP supplies a voltage reference
> and a temperature sensor feature that are gathered in the band
> gap voltage and temperature sensor (VBGAPTS) module. The band
> gap provides current and voltage reference for its internal
> circuits and other analog IP blocks. The analog-to-digital
> converter (ADC) produces an output value that is proportional
> to the silicon temperature.
>
> This patch provides a platform driver which expose this feature.
> It is moduled as a MFD child of the System Control Module core
> MFD driver.
>
> This driver provides only APIs to access the device properties,
> like temperature, thresholds and update rate.
>
> Signed-off-by: Eduardo Valentin <eduardo.valen...@ti.com>
> Signed-off-by: Keerthy <j-keer...@ti.com>
> ---
>  .../devicetree/bindings/thermal/omap_bandgap.txt   |   27 +
>  drivers/thermal/Kconfig                            |   13 +
>  drivers/thermal/Makefile                           |    4 +-
>  drivers/thermal/omap-bandgap.c                     | 1601 
> ++++++++++++++++++++
>  drivers/thermal/omap-bandgap.h                     |   63 +
>  5 files changed, 1707 insertions(+), 1 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/thermal/omap_bandgap.txt
>  create mode 100644 drivers/thermal/omap-bandgap.c
>  create mode 100644 drivers/thermal/omap-bandgap.h
>
>
Add private spin lock in omap-bandgap driver to prevent blocking of
control module general registers access.
I wasn't able to test - I have panda 4430 board.

TODO:
Prevent over-usage of spin_lock/spin_unlock for sequential calls of
bg_writel().

Signed-off-by: Konstantin Baydarov <kbaida...@dev.rtsoft.ru>

Index: omap-thermal/drivers/mfd/omap-control-core.c
===================================================================
--- omap-thermal.orig/drivers/mfd/omap-control-core.c
+++ omap-thermal/drivers/mfd/omap-control-core.c
@@ -67,6 +67,19 @@ EXPORT_SYMBOL_GPL(omap_control_readl);
 int omap_control_writel(struct device *dev, u32 val, u32 reg)
 {
        struct omap_control *omap_control = dev_get_drvdata(dev);
+
+       if (!omap_control)
+               return -EINVAL;
+
+       writel(val, omap_control->base + reg);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(omap_control_writel);
+
+int omap_control_lock_writel(struct device *dev, u32 val, u32 reg)
+{
+       struct omap_control *omap_control = dev_get_drvdata(dev);
        unsigned long flags;
 
        if (!omap_control)
@@ -78,7 +91,7 @@ int omap_control_writel(struct device *d
 
        return 0;
 }
-EXPORT_SYMBOL_GPL(omap_control_writel);
+EXPORT_SYMBOL_GPL(omap_control_lock_writel);
 
 /**
  * omap_control_get: returns the control module device pinter
@@ -136,6 +149,9 @@ static int __devinit omap_control_probe(
        struct device_node *np = dev->of_node;
        struct omap_control *omap_control;
 
+       printk("\n\t\t **** omap_control_probe(): enter ");
+       dump_stack();
+
        omap_control = devm_kzalloc(dev, sizeof(*omap_control), GFP_KERNEL);
        if (!omap_control) {
                dev_err(dev, "not enough memory for omap_control\n");
Index: omap-thermal/drivers/thermal/omap-bandgap.c
===================================================================
--- omap-thermal.orig/drivers/thermal/omap-bandgap.c
+++ omap-thermal/drivers/thermal/omap-bandgap.c
@@ -154,6 +154,7 @@ struct temp_sensor_registers {
        u32     status_cold_mask;
 
        u32     bgap_efuse;
+       spinlock_t      bg_reg_lock;
 };
 
 /**
@@ -579,6 +580,17 @@ omap5430_adc_to_temp[OMAP5430_ADC_END_VA
        124600, 124900, 125000, 125000, 125000, 125000,
 };
 
+static int bg_writel(struct device *dev, u32 val, u32 reg, spinlock_t *lock)
+{
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(lock, flags);
+       ret = omap_control_writel(dev, val, reg);
+       spin_unlock_irqrestore(lock, flags);
+       return ret;
+}
+
 static irqreturn_t talert_irq_handler(int irq, void *data)
 {
        struct omap_bandgap *bg_ptr = data;
@@ -615,7 +627,7 @@ static irqreturn_t talert_irq_handler(in
                        ctrl |= tsr->mask_hot_mask;
                }
 
-               r |= omap_control_writel(cdev, ctrl, tsr->bgap_mask_ctrl);
+               r |= bg_writel(cdev, ctrl, tsr->bgap_mask_ctrl, 
&tsr->bg_reg_lock);
 
                if (r) {
                        dev_err(bg_ptr->dev, "failed to ack talert 
interrupt\n");
@@ -705,7 +717,7 @@ static int temp_sensor_unmask_interrupts
                reg_val |= tsr->mask_cold_mask;
        else
                reg_val &= ~tsr->mask_cold_mask;
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_mask_ctrl);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_mask_ctrl, &tsr->bg_reg_lock);
 
        if (err) {
                dev_err(bg_ptr->dev, "failed to unmask interrupts\n");
@@ -751,14 +763,14 @@ int temp_sensor_configure_thot(struct om
                /* write the new t_cold value */
                reg_val = thresh_val & (~tsr->threshold_tcold_mask);
                reg_val |= cold << __ffs(tsr->threshold_tcold_mask);
-               err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+               err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, 
&tsr->bg_reg_lock);
                thresh_val = reg_val;
        }
 
        /* write the new t_hot value */
        reg_val = thresh_val & ~tsr->threshold_thot_mask;
        reg_val |= (t_hot << __ffs(tsr->threshold_thot_mask));
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram thot threshold\n");
                return -EIO;
@@ -782,7 +794,7 @@ int temp_sensor_init_talert_thresholds(s
        /* write the new t_cold value */
        reg_val = thresh_val & ~tsr->threshold_tcold_mask;
        reg_val |= (t_cold << __ffs(tsr->threshold_tcold_mask));
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram tcold threshold\n");
                return -EIO;
@@ -793,7 +805,7 @@ int temp_sensor_init_talert_thresholds(s
        /* write the new t_hot value */
        reg_val = thresh_val & ~tsr->threshold_thot_mask;
        reg_val |= (t_hot << __ffs(tsr->threshold_thot_mask));
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram thot threshold\n");
                return -EIO;
@@ -802,7 +814,7 @@ int temp_sensor_init_talert_thresholds(s
        err = omap_control_readl(cdev, tsr->bgap_mask_ctrl, &reg_val);
        reg_val |= tsr->mask_hot_mask;
        reg_val |= tsr->mask_cold_mask;
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_mask_ctrl);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_mask_ctrl, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram thot threshold\n");
                return -EIO;
@@ -833,14 +845,14 @@ int temp_sensor_configure_tcold(struct o
                /* write the new t_hot value */
                reg_val = thresh_val & (~tsr->threshold_thot_mask);
                reg_val |= hot << __ffs(tsr->threshold_thot_mask);
-               err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+               err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, 
&tsr->bg_reg_lock);
                thresh_val = reg_val;
        }
 
        /* write the new t_cold value */
        reg_val = thresh_val & ~tsr->threshold_tcold_mask;
        reg_val |= (t_cold << __ffs(tsr->threshold_tcold_mask));
-       err |= omap_control_writel(cdev, reg_val, tsr->bgap_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->bgap_threshold, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram tcold threshold\n");
                return -EIO;
@@ -861,7 +873,7 @@ static int temp_sensor_configure_tshut_h
        err = omap_control_readl(cdev, tsr->tshut_threshold, &reg_val);
        reg_val &= ~tsr->tshut_hot_mask;
        reg_val |= tshut_hot << __ffs(tsr->tshut_hot_mask);
-       err |= omap_control_writel(cdev, reg_val, tsr->tshut_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->tshut_threshold, 
&tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram tshut thot\n");
                return -EIO;
@@ -882,7 +894,7 @@ static int temp_sensor_configure_tshut_c
        err = omap_control_readl(cdev, tsr->tshut_threshold, &reg_val);
        reg_val &= ~tsr->tshut_cold_mask;
        reg_val |= tshut_cold << __ffs(tsr->tshut_cold_mask);
-       err |= omap_control_writel(cdev, reg_val, tsr->tshut_threshold);
+       err |= bg_writel(cdev, reg_val, tsr->tshut_threshold, 
&tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram tshut tcold\n");
                return -EIO;
@@ -903,7 +915,7 @@ static int configure_temp_sensor_counter
        err = omap_control_readl(cdev, tsr->bgap_counter, &val);
        val &= ~tsr->counter_mask;
        val |= counter << __ffs(tsr->counter_mask);
-       err |= omap_control_writel(cdev, val, tsr->bgap_counter);
+       err |= bg_writel(cdev, val, tsr->bgap_counter, &tsr->bg_reg_lock);
        if (err) {
                dev_err(bg_ptr->dev, "failed to reprogram tshut tcold\n");
                return -EIO;
@@ -1124,7 +1136,7 @@ static int enable_continuous_mode(struct
                tsr = bg_ptr->pdata->sensors[i].registers;
                r = omap_control_readl(cdev, tsr->bgap_mode_ctrl, &val);
                val |= 1 << __ffs(tsr->mode_ctrl_mask);
-               r |= omap_control_writel(cdev, val, tsr->bgap_mode_ctrl);
+               r |= bg_writel(cdev, val, tsr->bgap_mode_ctrl, 
&tsr->bg_reg_lock);
                if (r)
                        dev_err(bg_ptr->dev, "could not save sensor %d\n", i);
        }
@@ -1342,6 +1354,9 @@ int __devinit omap_bandgap_probe(struct
                u32 val;
 
                tsr = bg_ptr->pdata->sensors[i].registers;
+               /* Initialize register lock */
+               spin_lock_init(&tsr->bg_reg_lock);
+
                /*
                 * check if the efuse has a non-zero value if not
                 * it is an untrimmed sample and the temperatures
@@ -1482,12 +1497,12 @@ omap_bandgap_force_single_read(struct om
        /* Select single conversion mode */
        err = omap_control_readl(cdev, tsr->bgap_mode_ctrl, &temp);
        temp &= ~(1 << __ffs(tsr->mode_ctrl_mask));
-       omap_control_writel(cdev, temp, tsr->bgap_mode_ctrl);
+       bg_writel(cdev, temp, tsr->bgap_mode_ctrl, &tsr->bg_reg_lock);
 
        /* Start of Conversion = 1 */
        err |= omap_control_readl(cdev, tsr->temp_sensor_ctrl, &temp);
        temp |= 1 << __ffs(tsr->bgap_soc_mask);
-       omap_control_writel(cdev, temp, tsr->temp_sensor_ctrl);
+       bg_writel(cdev, temp, tsr->temp_sensor_ctrl, &tsr->bg_reg_lock);
        /* Wait until DTEMP is updated */
        err |= omap_control_readl(cdev, tsr->temp_sensor_ctrl, &temp);
        temp &= (tsr->bgap_dtemp_mask);
@@ -1498,7 +1513,7 @@ omap_bandgap_force_single_read(struct om
        /* Start of Conversion = 0 */
        err |= omap_control_readl(cdev, tsr->temp_sensor_ctrl, &temp);
        temp &= ~(1 << __ffs(tsr->bgap_soc_mask));
-       err |= omap_control_writel(cdev, temp, tsr->temp_sensor_ctrl);
+       err |= bg_writel(cdev, temp, tsr->temp_sensor_ctrl, &tsr->bg_reg_lock);
 
        return err ? -EIO : 0;
 }
@@ -1519,20 +1534,20 @@ static int omap_bandgap_restore_ctxt(str
 
                err = omap_control_readl(cdev, tsr->bgap_counter, &val);
                if (val == 0) {
-                       err |= omap_control_writel(cdev, rval->bg_threshold,
-                                                  tsr->bgap_threshold);
-                       err |= omap_control_writel(cdev, rval->tshut_threshold,
-                                                  tsr->tshut_threshold);
+                       err |= bg_writel(cdev, rval->bg_threshold,
+                                                  tsr->bgap_threshold, 
&tsr->bg_reg_lock);
+                       err |= bg_writel(cdev, rval->tshut_threshold,
+                                                  tsr->tshut_threshold, 
&tsr->bg_reg_lock);
                        /* Force immediate temperature measurement and update
                         * of the DTEMP field
                         */
                        omap_bandgap_force_single_read(bg_ptr, i);
-                       err |= omap_control_writel(cdev, rval->bg_counter,
-                                                  tsr->bgap_counter);
-                       err |= omap_control_writel(cdev, rval->bg_mode_ctrl,
-                                                  tsr->bgap_mode_ctrl);
-                       err |= omap_control_writel(cdev, rval->bg_ctrl,
-                                                  tsr->bgap_mask_ctrl);
+                       err |= bg_writel(cdev, rval->bg_counter,
+                                                  tsr->bgap_counter, 
&tsr->bg_reg_lock);
+                       err |= bg_writel(cdev, rval->bg_mode_ctrl,
+                                                  tsr->bgap_mode_ctrl, 
&tsr->bg_reg_lock);
+                       err |= bg_writel(cdev, rval->bg_ctrl,
+                                                  tsr->bgap_mask_ctrl, 
&tsr->bg_reg_lock);
                } else {
                        err |= omap_control_readl(cdev, tsr->temp_sensor_ctrl,
                                                 &temp);
@@ -1543,8 +1558,8 @@ static int omap_bandgap_restore_ctxt(str
                                                          tsr->bgap_mask_ctrl,
                                                          &temp);
                                temp |= 1 << __ffs(tsr->mode_ctrl_mask);
-                               err |= omap_control_writel(cdev, temp,
-                                                          tsr->bgap_mask_ctrl);
+                               err |= bg_writel(cdev, temp,
+                                                          tsr->bgap_mask_ctrl, 
&tsr->bg_reg_lock);
                        }
                }
                if (err)
Index: omap-thermal/drivers/usb/otg/omap4-usb-phy.c
===================================================================
--- omap-thermal.orig/drivers/usb/otg/omap4-usb-phy.c
+++ omap-thermal/drivers/usb/otg/omap4-usb-phy.c
@@ -46,13 +46,13 @@ int omap4_usb_phy_power(struct device *d
        if (on) {
                ret = omap_control_readl(dev, CONTROL_DEV_CONF, &val);
                if (!ret && (val & PHY_PD)) {
-                       ret = omap_control_writel(dev, ~PHY_PD,
+                       ret = omap_control_lock_writel(dev, ~PHY_PD,
                                                  CONTROL_DEV_CONF);
                        /* XXX: add proper documentation for this delay */
                        mdelay(200);
                }
        } else {
-               ret = omap_control_writel(dev, PHY_PD, CONTROL_DEV_CONF);
+               ret = omap_control_lock_writel(dev, PHY_PD, CONTROL_DEV_CONF);
        }
 
        return ret;
@@ -74,7 +74,7 @@ EXPORT_SYMBOL_GPL(omap4_usb_phy_power);
  */
 int omap4_usb_phy_mailbox(struct device *dev, u32 val)
 {
-       return omap_control_writel(dev, val, CONTROL_USBOTGHS_CONTROL);
+       return omap_control_lock_writel(dev, val, CONTROL_USBOTGHS_CONTROL);
 }
 EXPORT_SYMBOL_GPL(omap4_usb_phy_mailbox);
 
Index: omap-thermal/include/linux/mfd/omap_control.h
===================================================================
--- omap-thermal.orig/include/linux/mfd/omap_control.h
+++ omap-thermal/include/linux/mfd/omap_control.h
@@ -43,6 +43,7 @@ struct omap_control {
 #ifdef CONFIG_MFD_OMAP_CONTROL
 extern int omap_control_readl(struct device *dev, u32 reg, u32 *val);
 extern int omap_control_writel(struct device *dev, u32 val, u32 reg);
+extern int omap_control_lock_writel(struct device *dev, u32 val, u32 reg);
 extern struct device *omap_control_get(void);
 extern void omap_control_put(struct device *dev);
 #else
@@ -55,6 +56,11 @@ static inline int omap_control_writel(st
 {
        return 0;
 }
+
+static inline int omap_control_lock_writel(struct device *dev, u32 val, u32 
reg)
+{
+       return 0;
+}
 
 static inline struct device *omap_control_get(void)
 {


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