/*
* R-Car Gen3 THS thermal sensor driver
* Based on rcar_thermal.c and work from Hien Dang and Khiem Nguyen.
*
* Copyright (C) 2016 Renesas Electronics Corporation.
* Copyright (C) 2016 Sang Engineering
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/thermal.h>
/* Register offsets */
#define REG_GEN3_IRQSTR 0x04
#define REG_GEN3_IRQMSK 0x08
#define REG_GEN3_IRQCTL 0x0C
#define REG_GEN3_IRQEN 0x10
#define REG_GEN3_IRQTEMP1 0x14
#define REG_GEN3_IRQTEMP2 0x18
#define REG_GEN3_IRQTEMP3 0x1C
#define REG_GEN3_CTSR 0x20
#define REG_GEN3_THCTR 0x20
#define REG_GEN3_TEMP 0x28
#define REG_GEN3_THCODE1 0x50
#define REG_GEN3_THCODE2 0x54
#define REG_GEN3_THCODE3 0x58
/* CTSR bits */
#define CTSR_PONM BIT(8)
#define CTSR_AOUT BIT(7)
#define CTSR_THBGR BIT(5)
#define CTSR_VMEN BIT(4)
#define CTSR_VMST BIT(1)
#define CTSR_THSST BIT(0)
/* THCTR bits */
#define THCTR_PONM BIT(6)
#define THCTR_THSST BIT(0)
#define CTEMP_MASK 0xFFF
#define MCELSIUS(temp) ((temp) * 1000)
#define GEN3_FUSE_MASK 0xFFF
#define TSC_MAX_NUM 3
/* Structure for thermal temperature calculation */
struct equation_coefs {
int a1;
int b1;
int a2;
int b2;
};
struct rcar_gen3_thermal_tsc {
void __iomem *base;
struct thermal_zone_device *zone;
struct equation_coefs coef;
};
struct rcar_gen3_thermal_priv {
struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
unsigned int num_tscs;
};
struct rcar_gen3_thermal_data {
void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc);
};
static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
u32 reg)
{
return ioread32(tsc->base + reg);
}
static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
u32 reg, u32 data)
{
iowrite32(data, tsc->base + reg);
}
/*
* Linear approximation for temperature
*
* [reg] = [temp] * a + b => [temp] = ([reg] - b) / a
*
* The constants a and b are calculated using two triplets of int values PTAT
* and THCODE. PTAT and THCODE can either be read from hardware or use hard
* coded values from driver. The formula to calculate a and b are taken from
* BSP and sparsely documented and understood.
*
* Examining the linear formula and the formula used to calculate constants a
* and b while knowing that the span for PTAT and THCODE values are between
* 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001.
* Integer also needs to be signed so that leaves 7 bits for binary
* fixed point scaling.
*/
#define FIXPT_SHIFT 7
#define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT)
#define FIXPT_DIV(_a, _b) DIV_ROUND_CLOSEST(((_a) << FIXPT_SHIFT), (_b))
#define FIXPT_TO_MCELSIUS(_x) ((_x) * 1000 >> FIXPT_SHIFT)
#define RCAR3_THERMAL_GRAN 500 /* mili Celsius */
/* no idea where these constants come from */
#define TJ_1 96
#define TJ_3 -41
static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef,
int *ptat, int *thcode)
{
int tj_2;
/* TODO: Find documentation and document constant calculation formula */
/*
* Division is not scaled in BSP and if scaled it might overflow
* the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled
*/
tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 137)
/ (ptat[0] - ptat[2])) - FIXPT_INT(41);
coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]),
tj_2 - FIXPT_INT(TJ_3));
coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3;
coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]),
tj_2 - FIXPT_INT(TJ_1));
coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1;
}
static int rcar_gen3_thermal_round(int temp)
{
int result, round_offs;
round_offs = temp >= 0 ? RCAR3_THERMAL_GRAN / 2 :
-RCAR3_THERMAL_GRAN / 2;
result = (temp + round_offs) / RCAR3_THERMAL_GRAN;
return result * RCAR3_THERMAL_GRAN;
}
static int rcar_gen3_thermal_get_temp(void *devdata, int *temp)
{
struct rcar_gen3_thermal_tsc *tsc = devdata;
int mcelsius, val1, val2;
u32 reg;
/* Read register and convert to mili Celsius */
reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;
val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1);
val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2);
mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2);
/* Make sure we are inside specifications */
if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125)))
return -EIO;
/* Round value to device granularity setting */
*temp = rcar_gen3_thermal_round(mcelsius);
return 0;
}
static struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = {
.get_temp = rcar_gen3_thermal_get_temp,
};
static void r8a7795_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
{
rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_THBGR);
rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, 0x0);
usleep_range(1000, 2000);
rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM);
rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN);
usleep_range(100, 200);
rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR,
CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN |
CTSR_VMST | CTSR_THSST);
usleep_range(1000, 2000);
}
static void r8a7796_thermal_init(struct rcar_gen3_thermal_tsc *tsc)
{
u32 reg_val;
reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
reg_val &= ~THCTR_PONM;
rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
usleep_range(1000, 2000);
rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F);
reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
reg_val |= THCTR_THSST;
rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);
usleep_range(1000, 2000);
}
static const struct rcar_gen3_thermal_data r8a7795_data = {
.thermal_init = r8a7795_thermal_init,
};
static const struct rcar_gen3_thermal_data r8a7796_data = {
.thermal_init = r8a7796_thermal_init,
};
static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
{ .compatible = "renesas,r8a7795-thermal", .data = &r8a7795_data},
{ .compatible = "renesas,r8a7796-thermal", .data = &r8a7796_data},
{},
};
MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);
static int rcar_gen3_thermal_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
pm_runtime_put(dev);
pm_runtime_disable(dev);
return 0;
}
static int rcar_gen3_thermal_probe(struct platform_device *pdev)
{
struct rcar_gen3_thermal_priv *priv;
struct device *dev = &pdev->dev;
struct resource *res;
struct thermal_zone_device *zone;
int ret, i;
const struct rcar_gen3_thermal_data *match_data =
of_device_get_match_data(dev);
/* default values if FUSEs are missing */
/* TODO: Read values from hardware on supported platforms */
int ptat[3] = { 2351, 1509, 435 };
int thcode[TSC_MAX_NUM][3] = {
{ 3248, 2800, 2221 },
{ 3245, 2795, 2216 },
{ 3250, 2805, 2237 },
};
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
pm_runtime_enable(dev);
pm_runtime_get_sync(dev);
for (i = 0; i < TSC_MAX_NUM; i++) {
struct rcar_gen3_thermal_tsc *tsc;
res = platform_get_resource(pdev, IORESOURCE_MEM, i);
if (!res)
break;
tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL);
if (!tsc) {
ret = -ENOMEM;
goto error_unregister;
}
tsc->base = devm_ioremap_resource(dev, res);
if (IS_ERR(tsc->base)) {
ret = PTR_ERR(tsc->base);
goto error_unregister;
}
priv->tscs[i] = tsc;
match_data->thermal_init(tsc);
rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]);
zone = devm_thermal_zone_of_sensor_register(dev, i, tsc,
&rcar_gen3_tz_of_ops);
if (IS_ERR(zone)) {
dev_err(dev, "Can't register thermal zone\n");
ret = PTR_ERR(zone);
goto error_unregister;
}
tsc->zone = zone;
}
priv->num_tscs = i;
if (!priv->num_tscs) {
ret = -ENODEV;
goto error_unregister;
}
return 0;
error_unregister:
rcar_gen3_thermal_remove(pdev);
return ret;
}
static struct platform_driver rcar_gen3_thermal_driver = {
.driver = {
.name = "rcar_gen3_thermal",
.of_match_table = rcar_gen3_thermal_dt_ids,
},
.probe = rcar_gen3_thermal_probe,
.remove = rcar_gen3_thermal_remove,
};
module_platform_driver(rcar_gen3_thermal_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver");
MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>");
