[mirror_ubuntu-jammy-kernel.git] / drivers / thermal / tango_thermal.c

// SPDX-License-Identifier: GPL-2.0-only
#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");
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
0b58c08b MG	2	#include <linux/io.h>
	3	#include <linux/delay.h>
	4	#include <linux/module.h>
	5	#include <linux/thermal.h>
	6	#include <linux/platform_device.h>
	7
	8	/*
	9	* According to a data sheet draft, "this temperature sensor uses a bandgap
	10	* type of circuit to compare a voltage which has a negative temperature
	11	* coefficient with a voltage that is proportional to absolute temperature.
	12	* A resistor bank allows 41 different temperature thresholds to be selected
	13	* and the logic output will then indicate whether the actual die temperature
	14	* lies above or below the selected threshold."
	15	*/
	16
	17	#define TEMPSI_CMD 0
	18	#define TEMPSI_RES 4
	19	#define TEMPSI_CFG 8
	20
	21	#define CMD_OFF 0
	22	#define CMD_ON 1
	23	#define CMD_READ 2
	24
	25	#define IDX_MIN 15
	26	#define IDX_MAX 40
	27
	28	struct tango_thermal_priv {
	29	void __iomem *base;
	30	int thresh_idx;
	31	};
	32
	33	static bool temp_above_thresh(void __iomem *base, int thresh_idx)
	34	{
	35	writel(CMD_READ \| thresh_idx << 8, base + TEMPSI_CMD);
	36	usleep_range(10, 20);
	37	writel(CMD_READ \| thresh_idx << 8, base + TEMPSI_CMD);
	38
	39	return readl(base + TEMPSI_RES);
	40	}
	41
	42	static int tango_get_temp(void arg, int res)
	43	{
	44	struct tango_thermal_priv *priv = arg;
	45	int idx = priv->thresh_idx;
	46
	47	if (temp_above_thresh(priv->base, idx)) {
	48	/* Search upward by incrementing thresh_idx */
	49	while (idx < IDX_MAX && temp_above_thresh(priv->base, ++idx))
	50	cpu_relax();
	51	idx = idx - 1; /* always return lower bound */
	52	} else {
	53	/* Search downward by decrementing thresh_idx */
	54	while (idx > IDX_MIN && !temp_above_thresh(priv->base, --idx))
	55	cpu_relax();
	56	}
	57
	58	res = (idx 9 / 2 - 38) * 1000; /* millidegrees Celsius */
	59	priv->thresh_idx = idx;
	60
	61	return 0;
	62	}
	63
	64	static const struct thermal_zone_of_device_ops ops = {
	65	.get_temp = tango_get_temp,
66	};
67
9dfe1a2f MG	68	static void tango_thermal_init(struct tango_thermal_priv *priv)
	69	{
	70	writel(0, priv->base + TEMPSI_CFG);
	71	writel(CMD_ON, priv->base + TEMPSI_CMD);
	72	}
	73
0b58c08b MG	74	static int tango_thermal_probe(struct platform_device *pdev)
	75	{
	76	struct resource *res;
	77	struct tango_thermal_priv *priv;
	78	struct thermal_zone_device *tzdev;
	79
	80	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
	81	if (!priv)
	82	return -ENOMEM;
	83
	84	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	85	priv->base = devm_ioremap_resource(&pdev->dev, res);
	86	if (IS_ERR(priv->base))
	87	return PTR_ERR(priv->base);
	88
9dfe1a2f	89	platform_set_drvdata(pdev, priv);
0b58c08b	90	priv->thresh_idx = IDX_MIN;
9dfe1a2f	91	tango_thermal_init(priv);
0b58c08b MG	92
0b58c08b MG	93	tzdev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0, priv, &ops);
bba07c13	94	return PTR_ERR_OR_ZERO(tzdev);
0b58c08b MG	95	}
0b58c08b MG	96
9dfe1a2f MG	97	static int __maybe_unused tango_thermal_resume(struct device *dev)
	98	{
	99	tango_thermal_init(dev_get_drvdata(dev));
	100	return 0;
	101	}
	102
	103	static SIMPLE_DEV_PM_OPS(tango_thermal_pm, NULL, tango_thermal_resume);
	104
0b58c08b MG	105	static const struct of_device_id tango_sensor_ids[] = {
	106	{
	107	.compatible = "sigma,smp8758-thermal",
	108	},
	109	{ /* sentinel */ }
	110	};
26d9339d	111	MODULE_DEVICE_TABLE(of, tango_sensor_ids);
0b58c08b MG	112
	113	static struct platform_driver tango_thermal_driver = {
	114	.probe = tango_thermal_probe,
	115	.driver = {
	116	.name = "tango-thermal",
	117	.of_match_table = tango_sensor_ids,
9dfe1a2f	118	.pm = &tango_thermal_pm,
0b58c08b MG	119	},
	120	};
	121
	122	module_platform_driver(tango_thermal_driver);
	123
	124	MODULE_LICENSE("GPL");
	125	MODULE_AUTHOR("Sigma Designs");
	126	MODULE_DESCRIPTION("Tango temperature sensor");