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