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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/thermal/tango_thermal.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/thermal/tango_thermal.c')
-rw-r--r-- | drivers/thermal/tango_thermal.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/drivers/thermal/tango_thermal.c b/drivers/thermal/tango_thermal.c new file mode 100644 index 000000000..4e67795cb --- /dev/null +++ b/drivers/thermal/tango_thermal.c @@ -0,0 +1,125 @@ +#include <linux/io.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/thermal.h> +#include <linux/platform_device.h> + +/* + * According to a data sheet draft, "this temperature sensor uses a bandgap + * type of circuit to compare a voltage which has a negative temperature + * coefficient with a voltage that is proportional to absolute temperature. + * A resistor bank allows 41 different temperature thresholds to be selected + * and the logic output will then indicate whether the actual die temperature + * lies above or below the selected threshold." + */ + +#define TEMPSI_CMD 0 +#define TEMPSI_RES 4 +#define TEMPSI_CFG 8 + +#define CMD_OFF 0 +#define CMD_ON 1 +#define CMD_READ 2 + +#define IDX_MIN 15 +#define IDX_MAX 40 + +struct tango_thermal_priv { + void __iomem *base; + int thresh_idx; +}; + +static bool temp_above_thresh(void __iomem *base, int thresh_idx) +{ + writel(CMD_READ | thresh_idx << 8, base + TEMPSI_CMD); + usleep_range(10, 20); + writel(CMD_READ | thresh_idx << 8, base + TEMPSI_CMD); + + return readl(base + TEMPSI_RES); +} + +static int tango_get_temp(void *arg, int *res) +{ + struct tango_thermal_priv *priv = arg; + int idx = priv->thresh_idx; + + if (temp_above_thresh(priv->base, idx)) { + /* Search upward by incrementing thresh_idx */ + while (idx < IDX_MAX && temp_above_thresh(priv->base, ++idx)) + cpu_relax(); + idx = idx - 1; /* always return lower bound */ + } else { + /* Search downward by decrementing thresh_idx */ + while (idx > IDX_MIN && !temp_above_thresh(priv->base, --idx)) + cpu_relax(); + } + + *res = (idx * 9 / 2 - 38) * 1000; /* millidegrees Celsius */ + priv->thresh_idx = idx; + + return 0; +} + +static const struct thermal_zone_of_device_ops ops = { + .get_temp = tango_get_temp, +}; + +static void tango_thermal_init(struct tango_thermal_priv *priv) +{ + writel(0, priv->base + TEMPSI_CFG); + writel(CMD_ON, priv->base + TEMPSI_CMD); +} + +static int tango_thermal_probe(struct platform_device *pdev) +{ + struct resource *res; + struct tango_thermal_priv *priv; + struct thermal_zone_device *tzdev; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + platform_set_drvdata(pdev, priv); + priv->thresh_idx = IDX_MIN; + tango_thermal_init(priv); + + tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &ops); + return PTR_ERR_OR_ZERO(tzdev); +} + +static int __maybe_unused tango_thermal_resume(struct device *dev) +{ + tango_thermal_init(dev_get_drvdata(dev)); + return 0; +} + +static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume); + +static const struct of_device_id tango_sensor_ids[] = { + { + .compatible = "sigma,smp8758-thermal", + }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, tango_sensor_ids); + +static struct platform_driver tango_thermal_driver = { + .probe = tango_thermal_probe, + .driver = { + .name = "tango-thermal", + .of_match_table = tango_sensor_ids, + .pm = &tango_thermal_pm, + }, +}; + +module_platform_driver(tango_thermal_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Sigma Designs"); +MODULE_DESCRIPTION("Tango temperature sensor"); |