/* Temperature on y axis and ADC-code on x-axis */
static inline int code_to_mdegC(u32 adc_code, const struct tsens_sensor *s)
{
int slope, offset;
slope = thermal_zone_get_slope(s->tzd);
offset = CAL_MDEGC - slope * s->offset;
return adc_code * slope + offset;
}
static int bcm2835_thermal_get_temp(void *d, int *temp)
{
struct bcm2835_thermal_data *data = d;
u32 val = readl(data->regs + BCM2835_TS_TSENSSTAT);
if (!(val & BCM2835_TS_TSENSSTAT_VALID))
return -EIO;
val &= BCM2835_TS_TSENSSTAT_DATA_MASK;
*temp = bcm2835_thermal_adc2temp(
val,
thermal_zone_get_offset(data->tz),
thermal_zone_get_slope(data->tz));
return 0;
}
static int bcm2835_thermal_probe(struct platform_device *pdev)
{
const struct of_device_id *match;
struct thermal_zone_device *tz;
struct bcm2835_thermal_data *data;
struct resource *res;
int err = 0;
u32 val;
unsigned long rate;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
match = of_match_device(bcm2835_thermal_of_match_table,
&pdev->dev);
if (!match)
return -EINVAL;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->regs = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(data->regs)) {
err = PTR_ERR(data->regs);
dev_err(&pdev->dev, "Could not get registers: %d\n", err);
return err;
}
data->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(data->clk)) {
err = PTR_ERR(data->clk);
if (err != -EPROBE_DEFER)
dev_err(&pdev->dev, "Could not get clk: %d\n", err);
return err;
}
err = clk_prepare_enable(data->clk);
if (err)
return err;
rate = clk_get_rate(data->clk);
if ((rate < 1920000) || (rate > 5000000))
dev_warn(&pdev->dev,
"Clock %pCn running at %pCr Hz is outside of the recommended range: 1.92 to 5MHz\n",
data->clk, data->clk);
/* register of thermal sensor and get info from DT */
tz = thermal_zone_of_sensor_register(&pdev->dev, 0, data,
&bcm2835_thermal_ops);
if (IS_ERR(tz)) {
err = PTR_ERR(tz);
dev_err(&pdev->dev,
"Failed to register the thermal device: %d\n",
err);
goto err_clk;
}
/*
* right now the FW does set up the HW-block, so we are not
* touching the configuration registers.
* But if the HW is not enabled, then set it up
* using "sane" values used by the firmware right now.
*/
val = readl(data->regs + BCM2835_TS_TSENSCTL);
if (!(val & BCM2835_TS_TSENSCTL_RSTB)) {
int trip_temp, offset, slope;
slope = thermal_zone_get_slope(tz);
offset = thermal_zone_get_offset(tz);
/*
* For now we deal only with critical, otherwise
* would need to iterate
*/
err = tz->ops->get_trip_temp(tz, 0, &trip_temp);
if (err < 0) {
dev_err(&pdev->dev,
"Not able to read trip_temp: %d\n",
err);
goto err_tz;
}
/* set bandgap reference voltage and enable voltage regulator */
val = (BCM2835_TS_TSENSCTL_CTRL_DEFAULT <<
BCM2835_TS_TSENSCTL_CTRL_SHIFT) |
BCM2835_TS_TSENSCTL_REGULEN;
/* use the recommended reset duration */
val |= (0xFE << BCM2835_TS_TSENSCTL_RSTDELAY_SHIFT);
/* trip_adc value from info */
val |= bcm2835_thermal_temp2adc(trip_temp,
offset,
slope)
<< BCM2835_TS_TSENSCTL_THOLD_SHIFT;
/* write the value back to the register as 2 steps */
writel(val, data->regs + BCM2835_TS_TSENSCTL);
val |= BCM2835_TS_TSENSCTL_RSTB;
writel(val, data->regs + BCM2835_TS_TSENSCTL);
}
data->tz = tz;
platform_set_drvdata(pdev, tz);
bcm2835_thermal_debugfs(pdev);
return 0;
err_tz:
thermal_zone_of_sensor_unregister(&pdev->dev, tz);
err_clk:
clk_disable_unprepare(data->clk);
return err;
}
