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256 lines
5.8 KiB
256 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Copyright (C) 2012 Sven Schnelle <[email protected]> |
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#include <linux/platform_device.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/rtc.h> |
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#include <linux/types.h> |
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#include <linux/bcd.h> |
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#include <linux/platform_data/rtc-ds2404.h> |
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#include <linux/delay.h> |
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#include <linux/gpio.h> |
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#include <linux/slab.h> |
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#include <linux/io.h> |
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#define DS2404_STATUS_REG 0x200 |
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#define DS2404_CONTROL_REG 0x201 |
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#define DS2404_RTC_REG 0x202 |
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#define DS2404_WRITE_SCRATCHPAD_CMD 0x0f |
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#define DS2404_READ_SCRATCHPAD_CMD 0xaa |
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#define DS2404_COPY_SCRATCHPAD_CMD 0x55 |
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#define DS2404_READ_MEMORY_CMD 0xf0 |
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#define DS2404_RST 0 |
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#define DS2404_CLK 1 |
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#define DS2404_DQ 2 |
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struct ds2404_gpio { |
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const char *name; |
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unsigned int gpio; |
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}; |
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struct ds2404 { |
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struct ds2404_gpio *gpio; |
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struct rtc_device *rtc; |
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}; |
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static struct ds2404_gpio ds2404_gpio[] = { |
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{ "RTC RST", 0 }, |
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{ "RTC CLK", 0 }, |
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{ "RTC DQ", 0 }, |
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}; |
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static int ds2404_gpio_map(struct ds2404 *chip, struct platform_device *pdev, |
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struct ds2404_platform_data *pdata) |
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{ |
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int i, err; |
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ds2404_gpio[DS2404_RST].gpio = pdata->gpio_rst; |
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ds2404_gpio[DS2404_CLK].gpio = pdata->gpio_clk; |
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ds2404_gpio[DS2404_DQ].gpio = pdata->gpio_dq; |
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for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) { |
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err = gpio_request(ds2404_gpio[i].gpio, ds2404_gpio[i].name); |
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if (err) { |
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dev_err(&pdev->dev, "error mapping gpio %s: %d\n", |
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ds2404_gpio[i].name, err); |
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goto err_request; |
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} |
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if (i != DS2404_DQ) |
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gpio_direction_output(ds2404_gpio[i].gpio, 1); |
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} |
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chip->gpio = ds2404_gpio; |
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return 0; |
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err_request: |
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while (--i >= 0) |
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gpio_free(ds2404_gpio[i].gpio); |
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return err; |
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} |
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static void ds2404_gpio_unmap(void *data) |
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{ |
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int i; |
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for (i = 0; i < ARRAY_SIZE(ds2404_gpio); i++) |
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gpio_free(ds2404_gpio[i].gpio); |
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} |
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static void ds2404_reset(struct device *dev) |
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{ |
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gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 0); |
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udelay(1000); |
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gpio_set_value(ds2404_gpio[DS2404_RST].gpio, 1); |
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gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); |
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gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 0); |
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udelay(10); |
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} |
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static void ds2404_write_byte(struct device *dev, u8 byte) |
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{ |
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int i; |
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gpio_direction_output(ds2404_gpio[DS2404_DQ].gpio, 1); |
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for (i = 0; i < 8; i++) { |
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gpio_set_value(ds2404_gpio[DS2404_DQ].gpio, byte & (1 << i)); |
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udelay(10); |
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gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); |
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udelay(10); |
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gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); |
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udelay(10); |
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} |
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} |
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static u8 ds2404_read_byte(struct device *dev) |
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{ |
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int i; |
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u8 ret = 0; |
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gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); |
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for (i = 0; i < 8; i++) { |
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gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 0); |
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udelay(10); |
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if (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) |
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ret |= 1 << i; |
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gpio_set_value(ds2404_gpio[DS2404_CLK].gpio, 1); |
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udelay(10); |
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} |
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return ret; |
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} |
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static void ds2404_read_memory(struct device *dev, u16 offset, |
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int length, u8 *out) |
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{ |
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ds2404_reset(dev); |
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ds2404_write_byte(dev, DS2404_READ_MEMORY_CMD); |
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ds2404_write_byte(dev, offset & 0xff); |
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ds2404_write_byte(dev, (offset >> 8) & 0xff); |
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while (length--) |
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*out++ = ds2404_read_byte(dev); |
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} |
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static void ds2404_write_memory(struct device *dev, u16 offset, |
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int length, u8 *out) |
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{ |
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int i; |
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u8 ta01, ta02, es; |
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ds2404_reset(dev); |
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ds2404_write_byte(dev, DS2404_WRITE_SCRATCHPAD_CMD); |
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ds2404_write_byte(dev, offset & 0xff); |
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ds2404_write_byte(dev, (offset >> 8) & 0xff); |
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for (i = 0; i < length; i++) |
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ds2404_write_byte(dev, out[i]); |
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ds2404_reset(dev); |
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ds2404_write_byte(dev, DS2404_READ_SCRATCHPAD_CMD); |
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ta01 = ds2404_read_byte(dev); |
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ta02 = ds2404_read_byte(dev); |
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es = ds2404_read_byte(dev); |
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for (i = 0; i < length; i++) { |
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if (out[i] != ds2404_read_byte(dev)) { |
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dev_err(dev, "read invalid data\n"); |
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return; |
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} |
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} |
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ds2404_reset(dev); |
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ds2404_write_byte(dev, DS2404_COPY_SCRATCHPAD_CMD); |
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ds2404_write_byte(dev, ta01); |
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ds2404_write_byte(dev, ta02); |
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ds2404_write_byte(dev, es); |
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gpio_direction_input(ds2404_gpio[DS2404_DQ].gpio); |
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while (gpio_get_value(ds2404_gpio[DS2404_DQ].gpio)) |
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; |
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} |
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static void ds2404_enable_osc(struct device *dev) |
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{ |
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u8 in[1] = { 0x10 }; /* enable oscillator */ |
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ds2404_write_memory(dev, 0x201, 1, in); |
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} |
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static int ds2404_read_time(struct device *dev, struct rtc_time *dt) |
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{ |
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unsigned long time = 0; |
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__le32 hw_time = 0; |
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ds2404_read_memory(dev, 0x203, 4, (u8 *)&hw_time); |
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time = le32_to_cpu(hw_time); |
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rtc_time64_to_tm(time, dt); |
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return 0; |
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} |
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static int ds2404_set_time(struct device *dev, struct rtc_time *dt) |
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{ |
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u32 time = cpu_to_le32(rtc_tm_to_time64(dt)); |
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ds2404_write_memory(dev, 0x203, 4, (u8 *)&time); |
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return 0; |
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} |
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static const struct rtc_class_ops ds2404_rtc_ops = { |
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.read_time = ds2404_read_time, |
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.set_time = ds2404_set_time, |
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}; |
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static int rtc_probe(struct platform_device *pdev) |
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{ |
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struct ds2404_platform_data *pdata = dev_get_platdata(&pdev->dev); |
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struct ds2404 *chip; |
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int retval = -EBUSY; |
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chip = devm_kzalloc(&pdev->dev, sizeof(struct ds2404), GFP_KERNEL); |
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if (!chip) |
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return -ENOMEM; |
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chip->rtc = devm_rtc_allocate_device(&pdev->dev); |
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if (IS_ERR(chip->rtc)) |
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return PTR_ERR(chip->rtc); |
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retval = ds2404_gpio_map(chip, pdev, pdata); |
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if (retval) |
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return retval; |
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retval = devm_add_action_or_reset(&pdev->dev, ds2404_gpio_unmap, chip); |
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if (retval) |
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return retval; |
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dev_info(&pdev->dev, "using GPIOs RST:%d, CLK:%d, DQ:%d\n", |
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chip->gpio[DS2404_RST].gpio, chip->gpio[DS2404_CLK].gpio, |
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chip->gpio[DS2404_DQ].gpio); |
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platform_set_drvdata(pdev, chip); |
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chip->rtc->ops = &ds2404_rtc_ops; |
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chip->rtc->range_max = U32_MAX; |
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retval = devm_rtc_register_device(chip->rtc); |
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if (retval) |
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return retval; |
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ds2404_enable_osc(&pdev->dev); |
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return 0; |
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} |
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static struct platform_driver rtc_device_driver = { |
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.probe = rtc_probe, |
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.driver = { |
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.name = "ds2404", |
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}, |
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}; |
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module_platform_driver(rtc_device_driver); |
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MODULE_DESCRIPTION("DS2404 RTC"); |
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MODULE_AUTHOR("Sven Schnelle"); |
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MODULE_LICENSE("GPL"); |
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MODULE_ALIAS("platform:ds2404");
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