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501 lines
11 KiB
501 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* An I2C driver for the Intersil ISL 12026 |
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* |
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* Copyright (c) 2018 Cavium, Inc. |
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*/ |
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#include <linux/bcd.h> |
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#include <linux/delay.h> |
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#include <linux/i2c.h> |
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#include <linux/module.h> |
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#include <linux/mutex.h> |
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#include <linux/nvmem-provider.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/rtc.h> |
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#include <linux/slab.h> |
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/* register offsets */ |
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#define ISL12026_REG_PWR 0x14 |
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# define ISL12026_REG_PWR_BSW BIT(6) |
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# define ISL12026_REG_PWR_SBIB BIT(7) |
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#define ISL12026_REG_SC 0x30 |
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#define ISL12026_REG_HR 0x32 |
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# define ISL12026_REG_HR_MIL BIT(7) /* military or 24 hour time */ |
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#define ISL12026_REG_SR 0x3f |
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# define ISL12026_REG_SR_RTCF BIT(0) |
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# define ISL12026_REG_SR_WEL BIT(1) |
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# define ISL12026_REG_SR_RWEL BIT(2) |
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# define ISL12026_REG_SR_MBZ BIT(3) |
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# define ISL12026_REG_SR_OSCF BIT(4) |
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/* The EEPROM array responds at i2c address 0x57 */ |
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#define ISL12026_EEPROM_ADDR 0x57 |
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#define ISL12026_PAGESIZE 16 |
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#define ISL12026_NVMEM_WRITE_TIME 20 |
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struct isl12026 { |
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struct rtc_device *rtc; |
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struct i2c_client *nvm_client; |
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}; |
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static int isl12026_read_reg(struct i2c_client *client, int reg) |
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{ |
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u8 addr[] = {0, reg}; |
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u8 val; |
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int ret; |
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struct i2c_msg msgs[] = { |
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{ |
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.addr = client->addr, |
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.flags = 0, |
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.len = sizeof(addr), |
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.buf = addr |
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}, { |
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.addr = client->addr, |
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.flags = I2C_M_RD, |
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.len = 1, |
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.buf = &val |
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} |
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}; |
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ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (ret != ARRAY_SIZE(msgs)) { |
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dev_err(&client->dev, "read reg error, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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} else { |
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ret = val; |
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} |
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return ret; |
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} |
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static int isl12026_arm_write(struct i2c_client *client) |
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{ |
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int ret; |
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u8 op[3]; |
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struct i2c_msg msg = { |
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.addr = client->addr, |
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.flags = 0, |
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.len = 1, |
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.buf = op |
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}; |
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/* Set SR.WEL */ |
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op[0] = 0; |
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op[1] = ISL12026_REG_SR; |
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op[2] = ISL12026_REG_SR_WEL; |
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msg.len = 3; |
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ret = i2c_transfer(client->adapter, &msg, 1); |
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if (ret != 1) { |
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dev_err(&client->dev, "write error SR.WEL, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} |
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/* Set SR.WEL and SR.RWEL */ |
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op[2] = ISL12026_REG_SR_WEL | ISL12026_REG_SR_RWEL; |
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msg.len = 3; |
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ret = i2c_transfer(client->adapter, &msg, 1); |
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if (ret != 1) { |
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dev_err(&client->dev, |
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"write error SR.WEL|SR.RWEL, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} else { |
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ret = 0; |
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} |
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out: |
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return ret; |
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} |
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static int isl12026_disarm_write(struct i2c_client *client) |
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{ |
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int ret; |
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u8 op[3] = {0, ISL12026_REG_SR, 0}; |
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struct i2c_msg msg = { |
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.addr = client->addr, |
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.flags = 0, |
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.len = sizeof(op), |
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.buf = op |
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}; |
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ret = i2c_transfer(client->adapter, &msg, 1); |
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if (ret != 1) { |
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dev_err(&client->dev, |
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"write error SR, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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} else { |
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ret = 0; |
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} |
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return ret; |
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} |
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static int isl12026_write_reg(struct i2c_client *client, int reg, u8 val) |
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{ |
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int ret; |
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u8 op[3] = {0, reg, val}; |
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struct i2c_msg msg = { |
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.addr = client->addr, |
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.flags = 0, |
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.len = sizeof(op), |
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.buf = op |
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}; |
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ret = isl12026_arm_write(client); |
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if (ret) |
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return ret; |
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ret = i2c_transfer(client->adapter, &msg, 1); |
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if (ret != 1) { |
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dev_err(&client->dev, "write error CCR, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} |
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msleep(ISL12026_NVMEM_WRITE_TIME); |
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ret = isl12026_disarm_write(client); |
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out: |
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return ret; |
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} |
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static int isl12026_rtc_set_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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int ret; |
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u8 op[10]; |
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struct i2c_msg msg = { |
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.addr = client->addr, |
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.flags = 0, |
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.len = sizeof(op), |
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.buf = op |
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}; |
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ret = isl12026_arm_write(client); |
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if (ret) |
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return ret; |
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/* Set the CCR registers */ |
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op[0] = 0; |
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op[1] = ISL12026_REG_SC; |
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op[2] = bin2bcd(tm->tm_sec); /* SC */ |
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op[3] = bin2bcd(tm->tm_min); /* MN */ |
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op[4] = bin2bcd(tm->tm_hour) | ISL12026_REG_HR_MIL; /* HR */ |
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op[5] = bin2bcd(tm->tm_mday); /* DT */ |
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op[6] = bin2bcd(tm->tm_mon + 1); /* MO */ |
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op[7] = bin2bcd(tm->tm_year % 100); /* YR */ |
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op[8] = bin2bcd(tm->tm_wday & 7); /* DW */ |
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op[9] = bin2bcd(tm->tm_year >= 100 ? 20 : 19); /* Y2K */ |
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ret = i2c_transfer(client->adapter, &msg, 1); |
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if (ret != 1) { |
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dev_err(&client->dev, "write error CCR, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} |
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ret = isl12026_disarm_write(client); |
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out: |
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return ret; |
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} |
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static int isl12026_rtc_read_time(struct device *dev, struct rtc_time *tm) |
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{ |
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struct i2c_client *client = to_i2c_client(dev); |
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u8 ccr[8]; |
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u8 addr[2]; |
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u8 sr; |
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int ret; |
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struct i2c_msg msgs[] = { |
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{ |
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.addr = client->addr, |
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.flags = 0, |
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.len = sizeof(addr), |
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.buf = addr |
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}, { |
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.addr = client->addr, |
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.flags = I2C_M_RD, |
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} |
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}; |
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/* First, read SR */ |
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addr[0] = 0; |
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addr[1] = ISL12026_REG_SR; |
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msgs[1].len = 1; |
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msgs[1].buf = &sr; |
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ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (ret != ARRAY_SIZE(msgs)) { |
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dev_err(&client->dev, "read error, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} |
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if (sr & ISL12026_REG_SR_RTCF) |
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dev_warn(&client->dev, "Real-Time Clock Failure on read\n"); |
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if (sr & ISL12026_REG_SR_OSCF) |
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dev_warn(&client->dev, "Oscillator Failure on read\n"); |
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/* Second, CCR regs */ |
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addr[0] = 0; |
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addr[1] = ISL12026_REG_SC; |
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msgs[1].len = sizeof(ccr); |
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msgs[1].buf = ccr; |
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ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); |
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if (ret != ARRAY_SIZE(msgs)) { |
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dev_err(&client->dev, "read error, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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goto out; |
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} |
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tm->tm_sec = bcd2bin(ccr[0] & 0x7F); |
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tm->tm_min = bcd2bin(ccr[1] & 0x7F); |
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if (ccr[2] & ISL12026_REG_HR_MIL) |
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tm->tm_hour = bcd2bin(ccr[2] & 0x3F); |
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else |
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tm->tm_hour = bcd2bin(ccr[2] & 0x1F) + |
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((ccr[2] & 0x20) ? 12 : 0); |
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tm->tm_mday = bcd2bin(ccr[3] & 0x3F); |
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tm->tm_mon = bcd2bin(ccr[4] & 0x1F) - 1; |
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tm->tm_year = bcd2bin(ccr[5]); |
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if (bcd2bin(ccr[7]) == 20) |
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tm->tm_year += 100; |
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tm->tm_wday = ccr[6] & 0x07; |
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ret = 0; |
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out: |
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return ret; |
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} |
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static const struct rtc_class_ops isl12026_rtc_ops = { |
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.read_time = isl12026_rtc_read_time, |
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.set_time = isl12026_rtc_set_time, |
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}; |
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static int isl12026_nvm_read(void *p, unsigned int offset, |
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void *val, size_t bytes) |
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{ |
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struct isl12026 *priv = p; |
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int ret; |
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u8 addr[2]; |
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struct i2c_msg msgs[] = { |
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{ |
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.addr = priv->nvm_client->addr, |
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.flags = 0, |
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.len = sizeof(addr), |
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.buf = addr |
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}, { |
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.addr = priv->nvm_client->addr, |
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.flags = I2C_M_RD, |
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.buf = val |
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} |
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}; |
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/* |
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* offset and bytes checked and limited by nvmem core, so |
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* proceed without further checks. |
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*/ |
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ret = mutex_lock_interruptible(&priv->rtc->ops_lock); |
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if (ret) |
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return ret; |
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/* 2 bytes of address, most significant first */ |
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addr[0] = offset >> 8; |
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addr[1] = offset; |
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msgs[1].len = bytes; |
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ret = i2c_transfer(priv->nvm_client->adapter, msgs, ARRAY_SIZE(msgs)); |
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mutex_unlock(&priv->rtc->ops_lock); |
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if (ret != ARRAY_SIZE(msgs)) { |
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dev_err(&priv->nvm_client->dev, |
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"nvmem read error, ret=%d\n", ret); |
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return ret < 0 ? ret : -EIO; |
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} |
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return 0; |
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} |
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static int isl12026_nvm_write(void *p, unsigned int offset, |
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void *val, size_t bytes) |
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{ |
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struct isl12026 *priv = p; |
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int ret; |
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u8 *v = val; |
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size_t chunk_size, num_written; |
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u8 payload[ISL12026_PAGESIZE + 2]; /* page + 2 address bytes */ |
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struct i2c_msg msgs[] = { |
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{ |
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.addr = priv->nvm_client->addr, |
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.flags = 0, |
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.buf = payload |
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} |
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}; |
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/* |
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* offset and bytes checked and limited by nvmem core, so |
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* proceed without further checks. |
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*/ |
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ret = mutex_lock_interruptible(&priv->rtc->ops_lock); |
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if (ret) |
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return ret; |
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num_written = 0; |
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while (bytes) { |
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chunk_size = round_down(offset, ISL12026_PAGESIZE) + |
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ISL12026_PAGESIZE - offset; |
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chunk_size = min(bytes, chunk_size); |
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/* |
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* 2 bytes of address, most significant first, followed |
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* by page data bytes |
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*/ |
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memcpy(payload + 2, v + num_written, chunk_size); |
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payload[0] = offset >> 8; |
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payload[1] = offset; |
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msgs[0].len = chunk_size + 2; |
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ret = i2c_transfer(priv->nvm_client->adapter, |
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msgs, ARRAY_SIZE(msgs)); |
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if (ret != ARRAY_SIZE(msgs)) { |
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dev_err(&priv->nvm_client->dev, |
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"nvmem write error, ret=%d\n", ret); |
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ret = ret < 0 ? ret : -EIO; |
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break; |
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} |
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ret = 0; |
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bytes -= chunk_size; |
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offset += chunk_size; |
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num_written += chunk_size; |
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msleep(ISL12026_NVMEM_WRITE_TIME); |
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} |
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mutex_unlock(&priv->rtc->ops_lock); |
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return ret; |
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} |
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static void isl12026_force_power_modes(struct i2c_client *client) |
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{ |
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int ret; |
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int pwr, requested_pwr; |
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u32 bsw_val, sbib_val; |
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bool set_bsw, set_sbib; |
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/* |
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* If we can read the of_property, set the specified value. |
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* If there is an error reading the of_property (likely |
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* because it does not exist), keep the current value. |
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*/ |
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ret = of_property_read_u32(client->dev.of_node, |
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"isil,pwr-bsw", &bsw_val); |
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set_bsw = (ret == 0); |
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ret = of_property_read_u32(client->dev.of_node, |
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"isil,pwr-sbib", &sbib_val); |
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set_sbib = (ret == 0); |
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/* Check if PWR.BSW and/or PWR.SBIB need specified values */ |
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if (!set_bsw && !set_sbib) |
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return; |
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pwr = isl12026_read_reg(client, ISL12026_REG_PWR); |
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if (pwr < 0) { |
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dev_warn(&client->dev, "Error: Failed to read PWR %d\n", pwr); |
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return; |
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} |
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requested_pwr = pwr; |
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if (set_bsw) { |
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if (bsw_val) |
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requested_pwr |= ISL12026_REG_PWR_BSW; |
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else |
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requested_pwr &= ~ISL12026_REG_PWR_BSW; |
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} /* else keep current BSW */ |
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if (set_sbib) { |
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if (sbib_val) |
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requested_pwr |= ISL12026_REG_PWR_SBIB; |
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else |
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requested_pwr &= ~ISL12026_REG_PWR_SBIB; |
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} /* else keep current SBIB */ |
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if (pwr >= 0 && pwr != requested_pwr) { |
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dev_dbg(&client->dev, "PWR: %02x\n", pwr); |
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dev_dbg(&client->dev, "Updating PWR to: %02x\n", requested_pwr); |
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isl12026_write_reg(client, ISL12026_REG_PWR, requested_pwr); |
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} |
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} |
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static int isl12026_probe_new(struct i2c_client *client) |
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{ |
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struct isl12026 *priv; |
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int ret; |
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struct nvmem_config nvm_cfg = { |
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.name = "isl12026-", |
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.base_dev = &client->dev, |
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.stride = 1, |
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.word_size = 1, |
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.size = 512, |
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.reg_read = isl12026_nvm_read, |
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.reg_write = isl12026_nvm_write, |
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}; |
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if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) |
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return -ENODEV; |
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priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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i2c_set_clientdata(client, priv); |
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isl12026_force_power_modes(client); |
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priv->nvm_client = i2c_new_dummy_device(client->adapter, ISL12026_EEPROM_ADDR); |
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if (IS_ERR(priv->nvm_client)) |
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return PTR_ERR(priv->nvm_client); |
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priv->rtc = devm_rtc_allocate_device(&client->dev); |
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ret = PTR_ERR_OR_ZERO(priv->rtc); |
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if (ret) |
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return ret; |
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priv->rtc->ops = &isl12026_rtc_ops; |
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nvm_cfg.priv = priv; |
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ret = devm_rtc_nvmem_register(priv->rtc, &nvm_cfg); |
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if (ret) |
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return ret; |
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return devm_rtc_register_device(priv->rtc); |
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} |
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static int isl12026_remove(struct i2c_client *client) |
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{ |
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struct isl12026 *priv = i2c_get_clientdata(client); |
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i2c_unregister_device(priv->nvm_client); |
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return 0; |
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} |
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static const struct of_device_id isl12026_dt_match[] = { |
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{ .compatible = "isil,isl12026" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, isl12026_dt_match); |
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static struct i2c_driver isl12026_driver = { |
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.driver = { |
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.name = "rtc-isl12026", |
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.of_match_table = isl12026_dt_match, |
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}, |
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.probe_new = isl12026_probe_new, |
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.remove = isl12026_remove, |
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}; |
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module_i2c_driver(isl12026_driver); |
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MODULE_DESCRIPTION("ISL 12026 RTC driver"); |
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MODULE_LICENSE("GPL");
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