511 lines
10 KiB
C
511 lines
10 KiB
C
/*
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* CS2000 -- CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
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*
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* Copyright (C) 2015 Renesas Electronics Corporation
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* Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
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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 version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/clk-provider.h>
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#include <linux/delay.h>
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#include <linux/clk.h>
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#include <linux/i2c.h>
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#include <linux/of_device.h>
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#include <linux/module.h>
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#define CH_MAX 4
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#define RATIO_REG_SIZE 4
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#define DEVICE_ID 0x1
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#define DEVICE_CTRL 0x2
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#define DEVICE_CFG1 0x3
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#define DEVICE_CFG2 0x4
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#define GLOBAL_CFG 0x5
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#define Ratio_Add(x, nth) (6 + (x * 4) + (nth))
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#define Ratio_Val(x, nth) ((x >> (24 - (8 * nth))) & 0xFF)
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#define Val_Ratio(x, nth) ((x & 0xFF) << (24 - (8 * nth)))
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#define FUNC_CFG1 0x16
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#define FUNC_CFG2 0x17
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/* DEVICE_ID */
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#define REVISION_MASK (0x7)
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#define REVISION_B2_B3 (0x4)
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#define REVISION_C1 (0x6)
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/* DEVICE_CTRL */
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#define PLL_UNLOCK (1 << 7)
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/* DEVICE_CFG1 */
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#define RSEL(x) (((x) & 0x3) << 3)
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#define RSEL_MASK RSEL(0x3)
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#define ENDEV1 (0x1)
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/* GLOBAL_CFG */
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#define ENDEV2 (0x1)
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#define CH_SIZE_ERR(ch) ((ch < 0) || (ch >= CH_MAX))
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#define hw_to_priv(_hw) container_of(_hw, struct cs2000_priv, hw)
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#define priv_to_client(priv) (priv->client)
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#define priv_to_dev(priv) (&(priv_to_client(priv)->dev))
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#define CLK_IN 0
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#define REF_CLK 1
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#define CLK_MAX 2
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struct cs2000_priv {
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struct clk_hw hw;
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struct i2c_client *client;
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struct clk *clk_in;
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struct clk *ref_clk;
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struct clk *clk_out;
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};
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static const struct of_device_id cs2000_of_match[] = {
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{ .compatible = "cirrus,cs2000-cp", },
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{},
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};
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MODULE_DEVICE_TABLE(of, cs2000_of_match);
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static const struct i2c_device_id cs2000_id[] = {
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{ "cs2000-cp", },
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{}
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};
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MODULE_DEVICE_TABLE(i2c, cs2000_id);
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#define cs2000_read(priv, addr) \
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i2c_smbus_read_byte_data(priv_to_client(priv), addr)
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#define cs2000_write(priv, addr, val) \
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i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
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static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
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{
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s32 data;
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data = cs2000_read(priv, addr);
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if (data < 0)
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return data;
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data &= ~mask;
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data |= (val & mask);
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return cs2000_write(priv, addr, data);
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}
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static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
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{
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int ret;
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ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
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enable ? ENDEV1 : 0);
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if (ret < 0)
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return ret;
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ret = cs2000_bset(priv, GLOBAL_CFG, ENDEV2,
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enable ? ENDEV2 : 0);
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if (ret < 0)
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return ret;
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return 0;
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}
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static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
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u32 rate_in)
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{
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u32 val;
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if (rate_in >= 32000000 && rate_in < 56000000)
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val = 0x0;
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else if (rate_in >= 16000000 && rate_in < 28000000)
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val = 0x1;
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else if (rate_in >= 8000000 && rate_in < 14000000)
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val = 0x2;
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else
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return -EINVAL;
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return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
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}
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static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
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{
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struct device *dev = priv_to_dev(priv);
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s32 val;
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unsigned int i;
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for (i = 0; i < 256; i++) {
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val = cs2000_read(priv, DEVICE_CTRL);
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if (val < 0)
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return val;
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if (!(val & PLL_UNLOCK))
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return 0;
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udelay(1);
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}
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dev_err(dev, "pll lock failed\n");
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return -ETIMEDOUT;
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}
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static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
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{
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/* enable both AUX_OUT, CLK_OUT */
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return cs2000_write(priv, DEVICE_CTRL, enable ? 0 : 0x3);
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}
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static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
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{
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u64 ratio;
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/*
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* ratio = rate_out / rate_in * 2^20
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*
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* To avoid over flow, rate_out is u64.
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* The result should be u32.
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*/
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ratio = (u64)rate_out << 20;
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do_div(ratio, rate_in);
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return ratio;
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}
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static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
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{
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u64 rate_out;
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/*
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* ratio = rate_out / rate_in * 2^20
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*
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* To avoid over flow, rate_out is u64.
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* The result should be u32 or unsigned long.
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*/
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rate_out = (u64)ratio * rate_in;
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return rate_out >> 20;
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}
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static int cs2000_ratio_set(struct cs2000_priv *priv,
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int ch, u32 rate_in, u32 rate_out)
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{
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u32 val;
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unsigned int i;
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int ret;
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if (CH_SIZE_ERR(ch))
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return -EINVAL;
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val = cs2000_rate_to_ratio(rate_in, rate_out);
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for (i = 0; i < RATIO_REG_SIZE; i++) {
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ret = cs2000_write(priv,
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Ratio_Add(ch, i),
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Ratio_Val(val, i));
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if (ret < 0)
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return ret;
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}
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return 0;
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}
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static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
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{
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s32 tmp;
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u32 val;
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unsigned int i;
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val = 0;
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for (i = 0; i < RATIO_REG_SIZE; i++) {
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tmp = cs2000_read(priv, Ratio_Add(ch, i));
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if (tmp < 0)
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return 0;
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val |= Val_Ratio(tmp, i);
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}
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return val;
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}
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static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
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{
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int ret;
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if (CH_SIZE_ERR(ch))
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return -EINVAL;
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/*
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* FIXME
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*
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* this driver supports static ratio mode only at this point.
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*/
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ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
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if (ret < 0)
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return ret;
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ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
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if (ret < 0)
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return ret;
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return 0;
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}
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static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
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unsigned long parent_rate)
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{
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struct cs2000_priv *priv = hw_to_priv(hw);
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int ch = 0; /* it uses ch0 only at this point */
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u32 ratio;
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ratio = cs2000_ratio_get(priv, ch);
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return cs2000_ratio_to_rate(ratio, parent_rate);
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}
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static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
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unsigned long *parent_rate)
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{
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u32 ratio;
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ratio = cs2000_rate_to_ratio(*parent_rate, rate);
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return cs2000_ratio_to_rate(ratio, *parent_rate);
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}
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static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
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unsigned long rate, unsigned long parent_rate)
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{
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int ret;
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ret = cs2000_clk_in_bound_rate(priv, parent_rate);
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if (ret < 0)
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return ret;
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ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
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if (ret < 0)
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return ret;
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ret = cs2000_ratio_select(priv, ch);
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if (ret < 0)
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return ret;
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return 0;
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}
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static int cs2000_set_rate(struct clk_hw *hw,
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unsigned long rate, unsigned long parent_rate)
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{
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struct cs2000_priv *priv = hw_to_priv(hw);
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int ch = 0; /* it uses ch0 only at this point */
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return __cs2000_set_rate(priv, ch, rate, parent_rate);
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}
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static int cs2000_enable(struct clk_hw *hw)
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{
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struct cs2000_priv *priv = hw_to_priv(hw);
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int ret;
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ret = cs2000_enable_dev_config(priv, true);
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if (ret < 0)
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return ret;
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ret = cs2000_clk_out_enable(priv, true);
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if (ret < 0)
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return ret;
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ret = cs2000_wait_pll_lock(priv);
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if (ret < 0)
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return ret;
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return ret;
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}
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static void cs2000_disable(struct clk_hw *hw)
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{
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struct cs2000_priv *priv = hw_to_priv(hw);
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cs2000_enable_dev_config(priv, false);
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cs2000_clk_out_enable(priv, false);
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}
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static u8 cs2000_get_parent(struct clk_hw *hw)
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{
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/* always return REF_CLK */
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return REF_CLK;
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}
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static const struct clk_ops cs2000_ops = {
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.get_parent = cs2000_get_parent,
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.recalc_rate = cs2000_recalc_rate,
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.round_rate = cs2000_round_rate,
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.set_rate = cs2000_set_rate,
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.prepare = cs2000_enable,
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.unprepare = cs2000_disable,
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};
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static int cs2000_clk_get(struct cs2000_priv *priv)
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{
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struct i2c_client *client = priv_to_client(priv);
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struct device *dev = &client->dev;
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struct clk *clk_in, *ref_clk;
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clk_in = devm_clk_get(dev, "clk_in");
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/* not yet provided */
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if (IS_ERR(clk_in))
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return -EPROBE_DEFER;
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ref_clk = devm_clk_get(dev, "ref_clk");
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/* not yet provided */
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if (IS_ERR(ref_clk))
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return -EPROBE_DEFER;
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priv->clk_in = clk_in;
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priv->ref_clk = ref_clk;
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return 0;
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}
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static int cs2000_clk_register(struct cs2000_priv *priv)
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{
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struct device *dev = priv_to_dev(priv);
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struct device_node *np = dev->of_node;
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struct clk_init_data init;
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const char *name = np->name;
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struct clk *clk;
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static const char *parent_names[CLK_MAX];
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int ch = 0; /* it uses ch0 only at this point */
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int rate;
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int ret;
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of_property_read_string(np, "clock-output-names", &name);
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/*
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* set default rate as 1/1.
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* otherwise .set_rate which setup ratio
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* is never called if user requests 1/1 rate
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*/
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rate = clk_get_rate(priv->ref_clk);
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ret = __cs2000_set_rate(priv, ch, rate, rate);
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if (ret < 0)
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return ret;
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parent_names[CLK_IN] = __clk_get_name(priv->clk_in);
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parent_names[REF_CLK] = __clk_get_name(priv->ref_clk);
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init.name = name;
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init.ops = &cs2000_ops;
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init.flags = CLK_SET_RATE_GATE;
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init.parent_names = parent_names;
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init.num_parents = ARRAY_SIZE(parent_names);
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priv->hw.init = &init;
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clk = clk_register(dev, &priv->hw);
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
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if (ret < 0) {
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clk_unregister(clk);
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return ret;
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}
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priv->clk_out = clk;
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return 0;
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}
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static int cs2000_version_print(struct cs2000_priv *priv)
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{
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struct i2c_client *client = priv_to_client(priv);
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struct device *dev = &client->dev;
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s32 val;
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const char *revision;
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val = cs2000_read(priv, DEVICE_ID);
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if (val < 0)
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return val;
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/* CS2000 should be 0x0 */
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if (val >> 3)
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return -EIO;
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switch (val & REVISION_MASK) {
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case REVISION_B2_B3:
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revision = "B2 / B3";
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break;
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case REVISION_C1:
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revision = "C1";
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break;
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default:
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return -EIO;
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}
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dev_info(dev, "revision - %s\n", revision);
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return 0;
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}
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static int cs2000_remove(struct i2c_client *client)
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{
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struct cs2000_priv *priv = i2c_get_clientdata(client);
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struct device *dev = &client->dev;
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struct device_node *np = dev->of_node;
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of_clk_del_provider(np);
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clk_unregister(priv->clk_out);
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return 0;
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}
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static int cs2000_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct cs2000_priv *priv;
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struct device *dev = &client->dev;
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int ret;
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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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priv->client = client;
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i2c_set_clientdata(client, priv);
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ret = cs2000_clk_get(priv);
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if (ret < 0)
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return ret;
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ret = cs2000_clk_register(priv);
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if (ret < 0)
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return ret;
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ret = cs2000_version_print(priv);
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if (ret < 0)
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goto probe_err;
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return 0;
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probe_err:
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cs2000_remove(client);
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return ret;
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}
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static struct i2c_driver cs2000_driver = {
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.driver = {
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.name = "cs2000-cp",
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.of_match_table = cs2000_of_match,
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},
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.probe = cs2000_probe,
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.remove = cs2000_remove,
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.id_table = cs2000_id,
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};
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module_i2c_driver(cs2000_driver);
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MODULE_DESCRIPTION("CS2000-CP driver");
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MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
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MODULE_LICENSE("GPL v2");
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