Re: [PATCH 6/6 V4] hwmon: OMAP4: On die temperature sensor driver

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Hi

Some comments.

On Wed, 31 Aug 2011, Keerthy wrote:

> diff --git a/drivers/hwmon/omap_temp_sensor.c b/drivers/hwmon/omap_temp_sensor.c
> new file mode 100644
> index 0000000..67fa424
> --- /dev/null
> +++ b/drivers/hwmon/omap_temp_sensor.c
> @@ -0,0 +1,881 @@

You've done almost all the hard work to create kerneldoc-NANO compliant 
structure documentation, which is good.  But a few important things are 
missing.  Please review Documentation/kernel-doc-nano-HOWTO.txt.

> +/*

Should be /** to indicate kerneldoc.

> + * omap_temp_sensor structure

Should be "struct omap_temp_sensor" and should include a short 
description.

> + * @hwmon_dev - hwmon device pointer
> + * @pdev_dev - platform device pointer
> + * @clock - Clock pointer
> + * @registers - Pointer to structure with register offsets and bitfields
> + * @sensor_mutex - Mutex for sysfs, irq and PM
> + * @irq - MPU Irq number for thermal alert
> + * @phy_base - Physical base of the temp I/O
> + * @clk_rate - Holds current clock rate
> + * @temp_sensor_ctrl - temp sensor control register value
> + * @bg_ctrl - bandgap ctrl register value
> + * @bg_counter - bandgap counter value
> + * @bg_threshold - bandgap threshold register value
> + * @temp_sensor_tshut_threshold - bandgap tshut register value
> + * @clk_on - Manages the current clock state
> + */

> +struct omap_temp_sensor {
> +	struct device		*hwmon_dev;
> +	struct device		*pdev_dev;
> +	struct clk		*clock;
> +	struct omap_temp_sensor_registers *registers;
> +	struct mutex		sensor_mutex; /* Mutex for sysfs, irq and PM */
> +	unsigned int		irq;
> +	void __iomem		*phy_base;
> +	u32			clk_rate;
> +	u32			temp_sensor_ctrl;
> +	u32			bg_ctrl;
> +	u32			bg_counter;
> +	u32			bg_threshold;
> +	u32			temp_sensor_tshut_threshold;
> +	bool                    clk_on;
> +};
> +
> +/*
> + * Temperature values in milli degree celsius
> + * ADC code values from 530 to 923
> + */
> +static int adc_to_temp[394] = {
> +	-40000, -40000, -40000, -40000, -39800, -39400, -39000, -38600, -38200,
> +	-37800, -37300, -36800, -36400, -36000, -35600, -35200, -34800,
> +	-34300, -33800, -33400, -33000, -32600, -32200, -31800, -31300,
> +	-30800, -30400, -30000, -29600, -29200, -28700, -28200, -27800,
> +	-27400, -27000, -26600, -26200, -25700, -25200, -24800, -24400,
> +	-24000, -23600, -23200, -22700, -22200, -21800, -21400, -21000,
> +	-20600, -20200, -19700, -19200, -18800, -18400, -18000, -17600,
> +	-17200, -16700, -16200, -15800, -15400, -15000, -14600, -14200,
> +	-13700, -13200, -12800, -12400, -12000, -11600, -11200, -10700,
> +	-10200, -9800, -9400, -9000, -8600, -8200, -7700, -7200, -6800,
> +	-6400, -6000, -5600, -5200, -4800, -4300, -3800, -3400, -3000,
> +	-2600, -2200, -1800, -1300, -800, -400, 0, 400, 800, 1200, 1600,
> +	2100, 2600, 3000, 3400, 3800, 4200, 4600, 5100, 5600, 6000, 6400,
> +	6800, 7200, 7600, 8000, 8500, 9000, 9400, 9800, 10200, 10600, 11000,
> +	11400, 11900, 12400, 12800, 13200, 13600, 14000, 14400, 14800,
> +	15300, 15800, 16200, 16600, 17000, 17400, 17800, 18200, 18700,
> +	19200, 19600, 20000, 20400, 20800, 21200, 21600, 22100, 22600,
> +	23000, 23400, 23800, 24200, 24600, 25000, 25400, 25900, 26400,
> +	26800, 27200, 27600, 28000, 28400, 28800, 29300, 29800, 30200,
> +	30600, 31000, 31400, 31800, 32200, 32600, 33100, 33600, 34000,
> +	34400, 34800, 35200, 35600, 36000, 36400, 36800, 37300, 37800,
> +	38200, 38600, 39000, 39400, 39800, 40200, 40600, 41100, 41600,
> +	42000, 42400, 42800, 43200, 43600, 44000, 44400, 44800, 45300,
> +	45800, 46200, 46600, 47000, 47400, 47800, 48200, 48600, 49000,
> +	49500, 50000, 50400, 50800, 51200, 51600, 52000, 52400, 52800,
> +	53200, 53700, 54200, 54600, 55000, 55400, 55800, 56200, 56600,
> +	57000, 57400, 57800, 58200, 58700, 59200, 59600, 60000, 60400,
> +	60800, 61200, 61600, 62000, 62400, 62800, 63300, 63800, 64200,
> +	64600, 65000, 65400, 65800, 66200, 66600, 67000, 67400, 67800,
> +	68200, 68700, 69200, 69600, 70000, 70400, 70800, 71200, 71600,
> +	72000, 72400, 72800, 73200, 73600, 74100, 74600, 75000, 75400,
> +	75800, 76200, 76600, 77000, 77400, 77800, 78200, 78600, 79000,
> +	79400, 79800, 80300, 80800, 81200, 81600, 82000, 82400, 82800,
> +	83200, 83600, 84000, 84400, 84800, 85200, 85600, 86000, 86400,
> +	86800, 87300, 87800, 88200, 88600, 89000, 89400, 89800, 90200,
> +	90600, 91000, 91400, 91800, 92200, 92600, 93000, 93400, 93800,
> +	94200, 94600, 95000, 95500, 96000, 96400, 96800, 97200, 97600,
> +	98000, 98400, 98800, 99200, 99600, 100000, 100400, 100800, 101200,
> +	101600, 102000, 102400, 102800, 103200, 103600, 104000, 104400,
> +	104800, 105200, 105600, 106100, 106600, 107000, 107400, 107800,
> +	108200, 108600, 109000, 109400, 109800, 110200, 110600, 111000,
> +	111400, 111800, 112200, 112600, 113000, 113400, 113800, 114200,
> +	114600, 115000, 115400, 115800, 116200, 116600, 117000, 117400,
> +	117800, 118200, 118600, 119000, 119400, 119800, 120200, 120600,
> +	121000, 121400, 121800, 122200, 122600, 123000
> +};
> +
> +static unsigned long omap_temp_sensor_readl(struct omap_temp_sensor
> +					    *temp_sensor, u32 reg)
> +{
> +	return __raw_readl(temp_sensor->phy_base + reg);
> +}
> +
> +static void omap_temp_sensor_writel(struct omap_temp_sensor *temp_sensor,
> +				    u32 val, u32 reg)
> +{
> +	__raw_writel(val, temp_sensor->phy_base + reg);
> +}

These are all SCM register accesses and need to go through a SCM driver.

> +
> +static int adc_to_temp_conversion(int adc_val)
> +{
> +	return adc_to_temp[adc_val - OMAP_ADC_START_VALUE];
> +}
> +
> +static int temp_to_adc_conversion(long temp)
> +{
> +	int high, low, mid;
> +
> +	if (temp < adc_to_temp[0] ||
> +		temp > adc_to_temp[OMAP_ADC_END_VALUE - OMAP_ADC_START_VALUE])
> +		return -EINVAL;
> +
> +	high = OMAP_ADC_END_VALUE - OMAP_ADC_START_VALUE;
> +	low = 0;
> +	mid = (high + low) / 2;
> +
> +	while (low < high) {
> +		if (temp < adc_to_temp[mid])
> +			high = mid - 1;
> +		else
> +			low = mid + 1;
> +		mid = (low + high) / 2;
> +	}
> +
> +	return OMAP_ADC_START_VALUE + low;
> +}
> +
> +static void omap_configure_temp_sensor_counter(struct omap_temp_sensor
> +					       *temp_sensor, u32 counter)

It doesn't seem necessary to include 'omap' in all these static function names.

> +{
> +	u32 val;
> +
> +	val = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_counter);
> +	val &= ~temp_sensor->registers->counter_mask;
> +	val |= counter << __ffs(temp_sensor->registers->counter_mask);
> +	omap_temp_sensor_writel(temp_sensor, val,
> +			temp_sensor->registers->bgap_counter);
> +}
> +
> +static void omap_enable_continuous_mode(struct omap_temp_sensor *temp_sensor)
> +{
> +	u32 val;
> +
> +	val = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_mode_ctrl);
> +
> +	val |= 1 << __ffs(temp_sensor->registers->mode_ctrl_mask);
> +
> +	omap_temp_sensor_writel(temp_sensor, val,
> +			temp_sensor->registers->bgap_mode_ctrl);
> +}
> +
> +static void omap_temp_sensor_unmask_interrupts(struct omap_temp_sensor
> +						*temp_sensor, u8 hot, u8 cold)

Your earlier static function names didn't include 'temp_sensor', but
this one does.  I'd suggest picking a standard function naming scheme
and sticking to it.

> +{
> +	u32 reg_val;
> +
> +	reg_val = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_mask_ctrl);
> +	if (hot)
> +		reg_val |= temp_sensor->registers->mask_hot_mask;
> +	else
> +		reg_val &= ~temp_sensor->registers->mask_hot_mask;
> +
> +	if (cold)
> +		reg_val |= temp_sensor->registers->mask_cold_mask;
> +	else
> +		reg_val &= ~temp_sensor->registers->mask_cold_mask;
> +
> +	omap_temp_sensor_writel(temp_sensor, reg_val,
> +				temp_sensor->registers->bgap_mask_ctrl);
> +}
> +
> +static void add_hyst(int adc_val, int hyst_val, int *thresh_val)
> +{
> +	int temp = adc_to_temp_conversion(adc_val);
> +
> +	temp += hyst_val;
> +
> +	*thresh_val = temp_to_adc_conversion(temp);
> +}
> +
> +static void omap_temp_sensor_configure_thresholds_mask(struct omap_temp_sensor
> +	*temp_sensor, bool set_hot, bool set_cold, int t_hot, int t_cold)

Is there some reason why you don't just define a 

omap_temp_sensor_configure_hot_threshold()

and

omap_temp_sensor_configure_cold_threshold() 

?

Seems like that would be much more straightforward and would allow the 
removal of those set_{hot,cold} arguments.

> +{
> +	int		reg_val, cold, hot, temp;

This function is really big and should be split up into several smaller 
functions.  Common code should be shared if possible.

> +
> +	if (set_hot) {
> +		/* obtain the T cold value */
> +		cold = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_threshold);
> +		cold = (cold & temp_sensor->registers->threshold_tcold_mask)
> +			>> __ffs(temp_sensor->registers->threshold_tcold_mask);

This code should be hoisted up above the if statements.  Only a single
device read should be necessary to fetch both the hot and cold values.
Then the near-duplicate code below to read the hot temperature can be
removed.

In fact, given that this patch has almost the same code several times,
you should just put it into a static function or two and remove the
duplicate code.

> +
> +		if (t_hot < cold) {
> +			/* change the t_cold to t_hot - 5000 millidegrees */
> +			add_hyst(t_hot, NEG_HYST_VAL, &cold);
> +			/* write the new t_cold value */
> +			reg_val = omap_temp_sensor_readl(temp_sensor,
> +				temp_sensor->registers->bgap_threshold);
> +			reg_val &=
> +				~temp_sensor->registers->threshold_tcold_mask;
> +			reg_val |= cold <<
> +			__ffs(temp_sensor->registers->threshold_tcold_mask);

Looks like there are some indentation problems here.  Those are more 
important than 80-column issues.

Of course, you use temp_sensor->registers so much in this function, that 
many of the line length issues would go away if you used a shorter 
abbreviation at the beginning of this function, like:

      tsr = temp_sensor->registers;

> +			omap_temp_sensor_writel(temp_sensor, reg_val,
> +			temp_sensor->registers->bgap_threshold);
> +			t_cold = cold;
> +		}
> +
> +		/* write the new t_hot value */
> +		reg_val = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_threshold);
> +		reg_val &= ~temp_sensor->registers->threshold_thot_mask;
> +		reg_val |= (t_hot <<
> +			__ffs(temp_sensor->registers->threshold_thot_mask));
> +		omap_temp_sensor_writel(temp_sensor, reg_val,
> +			temp_sensor->registers->bgap_threshold);
> +	}
> +
> +	if (set_cold) {
> +		/* obtain the T HOT value */
> +		hot = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_threshold);
> +		hot = (hot & temp_sensor->registers->threshold_thot_mask) >>
> +                      __ffs(temp_sensor->registers->threshold_thot_mask);

See the earlier comment about hoisting.

> +		if (t_cold > hot) {
> +			/* change the t_hot to t_cold + 5000 millidegrees */
> +			add_hyst(t_cold, HYST_VAL, &hot);
> +			/* write the new t_hot value */
> +			reg_val = omap_temp_sensor_readl(temp_sensor,
> +				temp_sensor->registers->bgap_threshold);
> +			reg_val &=
> +				~temp_sensor->registers->threshold_thot_mask;
> +			reg_val |= (hot <<
> +			__ffs(temp_sensor->registers->threshold_thot_mask));
> +			omap_temp_sensor_writel(temp_sensor, reg_val,
> +				temp_sensor->registers->bgap_threshold);

This is a duplicate of earlier code.  Please consolidate.

> +			t_hot = hot;
> +		}
> +
> +		/* write the new t_cold value */
> +		reg_val = omap_temp_sensor_readl(temp_sensor,
> +				temp_sensor->registers->bgap_threshold);
> +		reg_val &= ~temp_sensor->registers->threshold_tcold_mask;
> +		reg_val |= t_cold <<
> +			__ffs(temp_sensor->registers->threshold_tcold_mask);
> +		omap_temp_sensor_writel(temp_sensor, reg_val,
> +			temp_sensor->registers->bgap_threshold);
> +	}
> +	 /* obtain the T cold value */
> +	cold = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_threshold);
> +	cold = (cold & temp_sensor->registers->threshold_tcold_mask)
> +		>> __ffs(temp_sensor->registers->threshold_tcold_mask);
> +
> +	/* obtain the T HOT value */
> +	hot = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_threshold);
> +	hot = (hot & temp_sensor->registers->threshold_thot_mask) >>
> +		__ffs(temp_sensor->registers->threshold_thot_mask);
> +
> +	/* Read the current temperature */
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->temp_sensor_ctrl);
> +	temp &= temp_sensor->registers->bgap_dtemp_mask;
> +
> +	/*
> +	 * If current temperature is in-between the hot and cold thresholds
> +	 * Enable both masks or in the init case enable both masks
> +	 */
> +	if ((temp > cold && temp < hot) || (set_cold && set_hot))
> +		omap_temp_sensor_unmask_interrupts(temp_sensor, 1, 1);
> +
> +	/*
> +	 * If user sets the HIGH threshold(t_hot) greater than the current
> +	 * temperature(temp) unmask the HOT interrupts
> +	 */
> +	else if (hot > temp)
> +		omap_temp_sensor_unmask_interrupts(temp_sensor, 1, 0);
> +
> +	/*
> +	 * If user sets the LOW threshold(t_cold) lower than the current
> +	 * temperature(temp) unmask the COLD interrupts
> +	 */
> +	else
> +		omap_temp_sensor_unmask_interrupts(temp_sensor, 0, 1);

This if statement is surely a violation of the spirit of 
Documentation/CodingStyle, if not the text itself.

If you really need an if statement like this, try something like:

     if ((temp > cold && temp < hot) || (set_cold && set_hot)) {
         /*
          * If current temperature is in-between the hot and cold thresholds
          * Enable both masks or in the init case enable both masks  
          */

             omap_temp_sensor_unmask_interrupts(temp_sensor, 1, 1);
     } else if (hot > temp) {
         /*
          * If user sets the HIGH threshold(t_hot) greater than the current
          * temperature(temp) unmask the HOT interrupts
          */
             omap_temp_sensor_unmask_interrupts(temp_sensor, 1, 0);
     } else {
         /*
          * If user sets the LOW threshold(t_cold) lower than the current
          * temperature(temp) unmask the COLD interrupts
          */
             omap_temp_sensor_unmask_interrupts(temp_sensor, 0, 1);
     }
  

> +}
> +
> +/* Sysfs hook functions */

These should be conditionally compiled out if sysfs isn't compiled in.

> +
> +static ssize_t show_temp_max(struct device *dev,
> +			struct device_attribute *devattr, char *buf)
> +{
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +	int temp;
> +
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_threshold);
> +	temp = (temp & temp_sensor->registers->threshold_thot_mask)
> +			>> __ffs(temp_sensor->registers->threshold_thot_mask);
> +	temp = adc_to_temp_conversion(temp);
> +
> +	return snprintf(buf, 16, "%d\n", temp);
> +}
> +
> +static ssize_t set_temp_max(struct device *dev,
> +			    struct device_attribute *devattr,
> +			    const char *buf, size_t count)
> +{
> +	struct omap_temp_sensor	*temp_sensor = dev_get_drvdata(dev);
> +	long			val;
> +	u32			t_hot;
> +
> +	if (strict_strtol(buf, 10, &val))
> +		return -EINVAL;
> +	if (val < MIN_TEMP - HYST_VAL)
> +		return -EINVAL;
> +
> +	t_hot = temp_to_adc_conversion(val);
> +	if (t_hot < 0)
> +		return t_hot;
> +
> +	mutex_lock(&temp_sensor->sensor_mutex);
> +	omap_temp_sensor_configure_thresholds_mask(temp_sensor, 1, 0,
> +							t_hot, 0);
> +	mutex_unlock(&temp_sensor->sensor_mutex);
> +
> +	return count;
> +}
> +
> +static ssize_t show_temp_max_hyst(struct device *dev,
> +		struct device_attribute *devattr, char *buf)
> +{
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +	u32			temp;
> +
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_threshold);
> +	temp = (temp & temp_sensor->registers->threshold_tcold_mask) >>
> +		__ffs(temp_sensor->registers->threshold_tcold_mask);
> +
> +	if (temp < OMAP_ADC_START_VALUE || temp > OMAP_ADC_END_VALUE) {
> +		dev_err(dev, "invalid value\n");
> +		return -EIO;
> +	}
> +
> +	temp = adc_to_temp_conversion(temp);
> +
> +	return snprintf(buf, 16, "%d\n", temp);
> +}
> +
> +static ssize_t set_temp_max_hyst(struct device *dev,
> +				 struct device_attribute *devattr,
> +				 const char *buf, size_t count)
> +{
> +	struct omap_temp_sensor		*temp_sensor = dev_get_drvdata(dev);
> +	u32				t_cold;
> +	long				val;
> +
> +	if (strict_strtol(buf, 10, &val)) {
> +		count = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (val > MAX_TEMP - HYST_VAL) {
> +		count = -EINVAL;
> +		goto out;
> +	}
> +
> +	t_cold = temp_to_adc_conversion(val);
> +	if (t_cold < 0)
> +		return t_cold;
> +
> +
> +	mutex_lock(&temp_sensor->sensor_mutex);
> +	omap_temp_sensor_configure_thresholds_mask(temp_sensor, 0, 1, 0,
> +							t_cold);
> +	mutex_unlock(&temp_sensor->sensor_mutex);
> +
> +out:
> +	return count;
> +}
> +
> +static ssize_t show_update_interval(struct device *dev,
> +			struct device_attribute *devattr, char *buf)
> +{
> +	struct omap_temp_sensor	*temp_sensor = dev_get_drvdata(dev);
> +	u32			temp;
> +
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_counter);
> +	temp = (temp & temp_sensor->registers->counter_mask) >>
> +			__ffs(temp_sensor->registers->counter_mask);
> +	temp = temp * 1000 / temp_sensor->clk_rate;
> +
> +	return sprintf(buf, "%d\n", temp);
> +}
> +
> +static ssize_t set_update_interval(struct device *dev,
> +			       struct device_attribute *devattr,
> +			       const char *buf, size_t count)
> +{
> +	struct omap_temp_sensor	*temp_sensor = dev_get_drvdata(dev);
> +	long			val;
> +
> +	if (strict_strtol(buf, 10, &val)) {
> +		count = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (val < 0)
> +		return -EINVAL;
> +	val *= temp_sensor->clk_rate / 1000;
> +	mutex_lock(&temp_sensor->sensor_mutex);
> +	omap_configure_temp_sensor_counter(temp_sensor, val);
> +	mutex_unlock(&temp_sensor->sensor_mutex);
> +out:
> +	return count;
> +}
> +
> +static int omap_temp_sensor_read_temp(struct device *dev,
> +				      struct device_attribute *devattr,
> +				      char *buf)
> +{
> +	struct omap_temp_sensor	*temp_sensor = dev_get_drvdata(dev);
> +	int			temp;
> +
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->temp_sensor_ctrl);
> +	temp &= temp_sensor->registers->bgap_dtemp_mask;
> +
> +	/* look up for temperature in the table and return the temperature */
> +	if (temp < OMAP_ADC_START_VALUE || temp > OMAP_ADC_END_VALUE)
> +		return -EIO;
> +
> +	temp = adc_to_temp[temp - OMAP_ADC_START_VALUE];
> +
> +	return sprintf(buf, "%d\n", temp);
> +}
> +
> +static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, omap_temp_sensor_read_temp,
> +			NULL, 0);
> +static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp_max,
> +			set_temp_max, 0);
> +static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, show_temp_max_hyst,
> +			set_temp_max_hyst, 0);
> +static SENSOR_DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO,
> +			show_update_interval, set_update_interval, 0);
> +
> +static struct attribute *omap_temp_sensor_attributes[] = {
> +	&sensor_dev_attr_temp1_input.dev_attr.attr,
> +	&sensor_dev_attr_temp1_max.dev_attr.attr,
> +	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
> +	&sensor_dev_attr_update_interval.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group omap_temp_sensor_group = {
> +	.attrs = omap_temp_sensor_attributes,
> +};
> +
> +static int omap_temp_sensor_clk_enable(struct omap_temp_sensor *temp_sensor)
> +{
> +	u32 ret = 0;
> +
> +	if (temp_sensor->clk_on) {
> +		dev_err(temp_sensor->pdev_dev, "clock already on\n");
> +		goto out;
> +	}
> +
> +	ret = pm_runtime_get_sync(temp_sensor->pdev_dev);
> +	if (ret < 0) {
> +		dev_err(temp_sensor->pdev_dev, "get sync failed\n");
> +		goto out;
> +	}
> +
> +	temp_sensor->clk_on = 1;
> +
> +out:
> +	return ret;
> +}
> +
> +static void omap_temp_sensor_clk_disable(struct omap_temp_sensor *temp_sensor)
> +{
> +	/* Gate the clock */
> +	pm_runtime_put_sync(temp_sensor->hwmon_dev);
> +	temp_sensor->clk_on = 0;
> +}
> +
> +static irqreturn_t omap_talert_irq_handler(int irq, void *data)
> +{
> +	struct omap_temp_sensor		*temp_sensor;
> +	int				t_hot, t_cold, temp;
> +
> +	temp_sensor = data;
> +	mutex_lock(&temp_sensor->sensor_mutex);
> +	/* Read the status of t_hot */
> +	t_hot = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_status)
> +			& temp_sensor->registers->status_hot_mask;
> +
> +	/* Read the status of t_cold */
> +	t_cold = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_status)
> +			& temp_sensor->registers->status_cold_mask;
> +
> +	temp = omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_mask_ctrl);
> +	/*
> +	 * One TALERT interrupt: Two sources
> +	 * If the interrupt is due to t_hot then mask t_hot and
> +	 * and unmask t_cold else mask t_cold and unmask t_hot
> +	 */
> +	if (t_hot) {
> +		temp &= ~temp_sensor->registers->mask_hot_mask;
> +		temp |= temp_sensor->registers->mask_cold_mask;
> +	} else if (t_cold) {
> +		temp &= ~temp_sensor->registers->mask_cold_mask;
> +		temp |= temp_sensor->registers->mask_hot_mask;
> +	}
> +
> +	omap_temp_sensor_writel(temp_sensor, temp,
> +		temp_sensor->registers->bgap_mask_ctrl);
> +
> +	if (temp_sensor->hwmon_dev)
> +		/* kobject_uvent to user space telling threshold crossed */
> +		kobject_uevent(&temp_sensor->hwmon_dev->kobj, KOBJ_CHANGE);
> +
> +	mutex_unlock(&temp_sensor->sensor_mutex);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int __devinit omap_temp_sensor_probe(struct platform_device *pdev)
> +{
> +	struct omap_temp_sensor_pdata	*pdata	= pdev->dev.platform_data;
> +	struct omap_temp_sensor		*temp_sensor;
> +	struct resource			*mem;
> +	int				ret = 0;
> +	int				clk_rate;
> +	u32				max_freq, min_freq;
> +
> +	if (!pdata) {
> +		dev_err(&pdev->dev, "platform data missing\n");
> +		return -EINVAL;
> +	}
> +
> +	temp_sensor = kzalloc(sizeof(*temp_sensor), GFP_KERNEL);
> +	if (!temp_sensor) {
> +		dev_err(&pdev->dev, "Memory allocation failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	mutex_init(&temp_sensor->sensor_mutex);
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!mem) {
> +		dev_err(&pdev->dev, "no mem resource\n");
> +		ret = -ENOMEM;
> +		goto plat_res_err;
> +	}
> +
> +	temp_sensor->irq = platform_get_irq_byname(pdev, "thermal_alert");
> +	if (temp_sensor->irq < 0) {
> +		dev_err(&pdev->dev, "get_irq_byname failed\n");
> +		ret = temp_sensor->irq;
> +		goto plat_res_err;
> +	}
> +
> +	temp_sensor->phy_base = ioremap(mem->start, resource_size(mem));
> +	if (!temp_sensor->phy_base) {
> +		dev_err(&pdev->dev, "ioremap failed\n");
> +		ret = -ENOMEM;
> +		goto plat_res_err;
> +	}
> +
> +	temp_sensor->clock = NULL;
> +	temp_sensor->registers = pdata->registers;
> +	temp_sensor->pdev_dev = &pdev->dev;
> +
> +	if (pdata->max_freq && pdata->min_freq) {
> +		max_freq = pdata->max_freq;
> +		min_freq = pdata->min_freq;
> +	} else {
> +		max_freq = MAX_FREQ;
> +		min_freq = MIN_FREQ;
> +	}
> +
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_irq_safe(&pdev->dev);
> +
> +	/*
> +	 * check if the efuse has a non-zero value if not
> +	 * it is an untrimmed sample and the temperatures
> +	 * may not be accurate
> +	 */
> +
> +	if (omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->bgap_efuse))
> +		dev_info(&pdev->dev,
> +			"Invalid EFUSE, Non-trimmed BGAP, Temp not accurate\n");
> +
> +	dev_set_drvdata(&pdev->dev, temp_sensor);
> +	temp_sensor->clock = clk_get(&pdev->dev, "fck");
> +	if (IS_ERR(temp_sensor->clock)) {
> +		ret = PTR_ERR(temp_sensor->clock);
> +		dev_err(&pdev->dev,
> +			"unable to get fclk: %d\n", ret);
> +		goto plat_res_err;
> +	}
> +
> +	ret = omap_temp_sensor_clk_enable(temp_sensor);
> +	if (ret)
> +		goto clken_err;
> +
> +	clk_rate = clk_round_rate(temp_sensor->clock, max_freq);
> +	if (clk_rate < min_freq || clk_rate == 0xffffffff) {
> +		ret = -ENODEV;
> +		goto clken_err;
> +	}
> +
> +	ret = clk_set_rate(temp_sensor->clock, clk_rate);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Cannot set clock rate\n");
> +		goto clken_err;
> +	}
> +
> +	temp_sensor->clk_rate = clk_rate;
> +	omap_enable_continuous_mode(temp_sensor);
> +	/* 1 clk cycle */
> +	omap_configure_temp_sensor_counter(temp_sensor, 1);
> +
> +	/* Wait till the first conversion is done wait for at least 1ms */
> +	usleep_range(1000, 2000);
> +
> +	/* Read the temperature once due to hw issue*/
> +	omap_temp_sensor_readl(temp_sensor,
> +			temp_sensor->registers->temp_sensor_ctrl);
> +
> +	/* Set 2 seconds time as default counter */
> +	omap_configure_temp_sensor_counter(temp_sensor,
> +						temp_sensor->clk_rate * 2);
> +
> +	ret = request_threaded_irq(temp_sensor->irq, NULL,
> +		omap_talert_irq_handler, IRQF_TRIGGER_RISING | IRQF_ONESHOT,
> +			"temp_sensor", temp_sensor);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Request threaded irq failed.\n");
> +		goto req_irq_err;
> +	}
> +
> +	ret = sysfs_create_group(&pdev->dev.kobj, &omap_temp_sensor_group);
> +	if (ret) {
> +		dev_err(&pdev->dev, "could not create sysfs files\n");
> +		goto sysfs_create_err;
> +	}
> +
> +	temp_sensor->hwmon_dev = hwmon_device_register(&pdev->dev);
> +	if (IS_ERR(temp_sensor->hwmon_dev)) {
> +		dev_err(&pdev->dev, "hwmon_device_register failed.\n");
> +		ret = PTR_ERR(temp_sensor->hwmon_dev);
> +		goto hwmon_reg_err;
> +	}
> +
> +	mutex_lock(&temp_sensor->sensor_mutex);
> +	omap_temp_sensor_configure_thresholds_mask(temp_sensor, 1, 1,
> +						T_HOT, T_COLD);
> +	mutex_unlock(&temp_sensor->sensor_mutex);
> +
> +	return 0;
> +
> +hwmon_reg_err:
> +	sysfs_remove_group(&temp_sensor->hwmon_dev->kobj,
> +				&omap_temp_sensor_group);
> +sysfs_create_err:
> +	free_irq(temp_sensor->irq, temp_sensor);
> +req_irq_err:
> +	omap_temp_sensor_clk_disable(temp_sensor);
> +clken_err:
> +	clk_put(temp_sensor->clock);
> +	iounmap(temp_sensor->phy_base);
> +plat_res_err:
> +	dev_set_drvdata(&pdev->dev, NULL);
> +	mutex_destroy(&temp_sensor->sensor_mutex);
> +	kfree(temp_sensor);
> +	return ret;
> +}
> +
> +static int __devexit omap_temp_sensor_remove(struct platform_device *pdev)
> +{
> +	struct omap_temp_sensor *temp_sensor = platform_get_drvdata(pdev);
> +
> +	hwmon_device_unregister(&pdev->dev);
> +	sysfs_remove_group(&temp_sensor->hwmon_dev->kobj,
> +			&omap_temp_sensor_group);
> +	free_irq(temp_sensor->irq, temp_sensor);
> +	omap_temp_sensor_clk_disable(temp_sensor);
> +	clk_put(temp_sensor->clock);
> +	iounmap(temp_sensor->phy_base);
> +	dev_set_drvdata(&pdev->dev, NULL);
> +	mutex_destroy(&temp_sensor->sensor_mutex);
> +	kfree(temp_sensor);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static void omap_temp_sensor_save_ctxt(struct omap_temp_sensor *temp_sensor)
> +{
> +	temp_sensor->temp_sensor_ctrl = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->temp_sensor_ctrl);
> +	temp_sensor->bg_ctrl = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_mask_ctrl);
> +	temp_sensor->bg_counter = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_counter);
> +	temp_sensor->bg_threshold = omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->bgap_threshold);
> +	temp_sensor->temp_sensor_tshut_threshold =
> +		omap_temp_sensor_readl(temp_sensor,
> +		temp_sensor->registers->thsut_threshold);
> +}
> +
> +static void omap_temp_sensor_restore_ctxt(struct omap_temp_sensor *temp_sensor)
> +{
> +	omap_temp_sensor_writel(temp_sensor,
> +				temp_sensor->temp_sensor_ctrl,
> +				temp_sensor->registers->temp_sensor_ctrl);
> +	omap_temp_sensor_writel(temp_sensor,
> +				temp_sensor->bg_ctrl,
> +				temp_sensor->registers->bgap_mask_ctrl);
> +	omap_temp_sensor_writel(temp_sensor,
> +				temp_sensor->bg_counter,
> +				temp_sensor->registers->bgap_counter);
> +	omap_temp_sensor_writel(temp_sensor,
> +				temp_sensor->bg_threshold,
> +				temp_sensor->registers->bgap_threshold);
> +	omap_temp_sensor_writel(temp_sensor,
> +				temp_sensor->temp_sensor_tshut_threshold,
> +				temp_sensor->registers->thsut_threshold);
> +}
> +
> +static int omap_temp_sensor_suspend(struct device *dev)
> +{
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +
> +	omap_temp_sensor_save_ctxt(temp_sensor);
> +
> +	return 0;
> +}
> +
> +static int omap_temp_sensor_resume(struct device *dev)
> +{
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +
> +	omap_temp_sensor_restore_ctxt(temp_sensor);
> +
> +	return 0;
> +}
> +
> +static int omap_temp_sensor_runtime_suspend(struct device *dev)
> +{
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +
> +	omap_temp_sensor_save_ctxt(temp_sensor);
> +
> +	return 0;
> +}
> +
> +static int omap_temp_sensor_runtime_resume(struct device *dev)
> +{
> +	static int context_loss_count;
> +	int temp;
> +	struct omap_temp_sensor *temp_sensor = dev_get_drvdata(dev);
> +
> +	temp = omap_device_get_context_loss_count(to_platform_device(dev));
> +
> +	if (temp != context_loss_count && context_loss_count != 0)
> +		omap_temp_sensor_restore_ctxt(temp_sensor);
> +
> +	context_loss_count = temp;
> +
> +	return 0;
> +}
> +
> +static int omap_temp_sensor_idle(struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops omap_temp_sensor_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(omap_temp_sensor_suspend,
> +			omap_temp_sensor_resume)
> +	SET_RUNTIME_PM_OPS(omap_temp_sensor_runtime_suspend,
> +			omap_temp_sensor_runtime_resume, omap_temp_sensor_idle)
> +};
> +
> +#define DEV_PM_OPS	(&omap_temp_sensor_dev_pm_ops)
> +#else
> +#define DEV_PM_OPS	NULL
> +#endif
> +
> +static struct platform_driver omap_temp_sensor_driver = {
> +	.probe = omap_temp_sensor_probe,
> +	.remove = omap_temp_sensor_remove,
> +	.driver = {
> +			.name = "omap_temp_sensor",
> +			.pm = DEV_PM_OPS,
> +		  },
> +};
> +
> +int __init omap_temp_sensor_init(void)
> +{
> +	return platform_driver_register(&omap_temp_sensor_driver);
> +}
> +module_init(omap_temp_sensor_init);
> +
> +static void __exit omap_temp_sensor_exit(void)
> +{
> +	platform_driver_unregister(&omap_temp_sensor_driver);
> +}
> +module_exit(omap_temp_sensor_exit);
> +
> +MODULE_DESCRIPTION("OMAP446X temperature sensor Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> +MODULE_AUTHOR("J Keerthy <j-keerthy@xxxxxx>");
> -- 
> 1.7.0.4
> 
> --
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> 


- Paul

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