#include #include #include #include #include /* * 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"); 84970ff3b32'>usb/atm/cxacru.c

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