// SPDX-License-Identifier: GPL-2.0 /* * Driver for the Renesas R-Car I2C unit * * Copyright (C) 2014-19 Wolfram Sang <[email protected]> * Copyright (C) 2011-2019 Renesas Electronics Corporation * * Copyright (C) 2012-14 Renesas Solutions Corp. * Kuninori Morimoto <[email protected]> * * This file is based on the drivers/i2c/busses/i2c-sh7760.c * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <[email protected]> */ #include <linux/bitops.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/dmaengine.h> #include <linux/dma-mapping.h> #include <linux/err.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/iopoll.h> #include <linux/i2c.h> #include <linux/i2c-smbus.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/pm_runtime.h> #include <linux/reset.h> #include <linux/slab.h> /* register offsets */ #define ICSCR … #define ICMCR … #define ICSSR … #define ICMSR … #define ICSIER … #define ICMIER … #define ICCCR … #define ICSAR … #define ICMAR … #define ICRXTX … #define ICCCR2 … #define ICMPR … #define ICHPR … #define ICLPR … #define ICFBSCR … #define ICDMAER … /* ICSCR */ #define SDBS … #define SIE … #define GCAE … #define FNA … /* ICMCR */ #define MDBS … #define FSCL … #define FSDA … #define OBPC … #define MIE … #define TSBE … #define FSB … #define ESG … /* ICSSR (also for ICSIER) */ #define GCAR … #define STM … #define SSR … #define SDE … #define SDT … #define SDR … #define SAR … /* ICMSR (also for ICMIE) */ #define MNR … #define MAL … #define MST … #define MDE … #define MDT … #define MDR … #define MAT … /* ICDMAER */ #define RSDMAE … #define TSDMAE … #define RMDMAE … #define TMDMAE … /* ICCCR2 */ #define FMPE … #define CDFD … #define HLSE … #define SME … /* ICFBSCR */ #define TCYC17 … #define RCAR_MIN_DMA_LEN … /* SCL low/high ratio 5:4 to meet all I2C timing specs (incl safety margin) */ #define RCAR_SCLD_RATIO … #define RCAR_SCHD_RATIO … /* * SMD should be smaller than SCLD/SCHD and is always around 20 in the docs. * Thus, we simply use 20 which works for low and high speeds. */ #define RCAR_DEFAULT_SMD … #define RCAR_BUS_PHASE_START … #define RCAR_BUS_PHASE_DATA … #define RCAR_BUS_PHASE_STOP … #define RCAR_IRQ_SEND … #define RCAR_IRQ_RECV … #define RCAR_IRQ_STOP … #define ID_LAST_MSG … #define ID_REP_AFTER_RD … #define ID_DONE … #define ID_ARBLOST … #define ID_NACK … #define ID_EPROTO … /* persistent flags */ #define ID_P_FMPLUS … #define ID_P_NOT_ATOMIC … #define ID_P_HOST_NOTIFY … #define ID_P_NO_RXDMA … #define ID_P_PM_BLOCKED … #define ID_P_MASK … enum rcar_i2c_type { … }; struct rcar_i2c_priv { … }; #define rcar_i2c_priv_to_dev(p) … #define rcar_i2c_is_recv(p) … static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val) { … } static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg) { … } static void rcar_i2c_clear_irq(struct rcar_i2c_priv *priv, u32 val) { … } static int rcar_i2c_get_scl(struct i2c_adapter *adap) { … } static void rcar_i2c_set_scl(struct i2c_adapter *adap, int val) { … } static void rcar_i2c_set_sda(struct i2c_adapter *adap, int val) { … } static int rcar_i2c_get_bus_free(struct i2c_adapter *adap) { … } static struct i2c_bus_recovery_info rcar_i2c_bri = …; static void rcar_i2c_init(struct rcar_i2c_priv *priv) { … } static void rcar_i2c_reset_slave(struct rcar_i2c_priv *priv) { … } static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) { … } static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv) { … } /* * We don't have a test case but the HW engineers say that the write order of * ICMSR and ICMCR depends on whether we issue START or REP_START. So, ICMSR * handling is outside of this function. First messages clear ICMSR before this * function, interrupt handlers clear the relevant bits after this function. */ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) { … } static void rcar_i2c_first_msg(struct rcar_i2c_priv *priv, struct i2c_msg *msgs, int num) { … } static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv) { … } static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv, bool terminate) { … } static void rcar_i2c_dma_callback(void *data) { … } static bool rcar_i2c_dma(struct rcar_i2c_priv *priv) { … } static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr) { … } static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr) { … } static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) { … } /* * This driver has a lock-free design because there are IP cores (at least * R-Car Gen2) which have an inherent race condition in their hardware design. * There, we need to switch to RCAR_BUS_PHASE_DATA as soon as possible after * the interrupt was generated, otherwise an unwanted repeated message gets * generated. It turned out that taking a spinlock at the beginning of the ISR * was already causing repeated messages. Thus, this driver was converted to * the now lockless behaviour. Please keep this in mind when hacking the driver. * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are * likely affected. Therefore, we have different interrupt handler entries. */ static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr) { … } static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr) { … } static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr) { … } static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev, enum dma_transfer_direction dir, dma_addr_t port_addr) { … } static void rcar_i2c_request_dma(struct rcar_i2c_priv *priv, struct i2c_msg *msg) { … } static void rcar_i2c_release_dma(struct rcar_i2c_priv *priv) { … } /* I2C is a special case, we need to poll the status of a reset */ static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv) { … } static int rcar_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { … } static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { … } static int rcar_reg_slave(struct i2c_client *slave) { … } static int rcar_unreg_slave(struct i2c_client *slave) { … } static u32 rcar_i2c_func(struct i2c_adapter *adap) { … } static const struct i2c_algorithm rcar_i2c_algo = …; static const struct i2c_adapter_quirks rcar_i2c_quirks = …; static const struct of_device_id rcar_i2c_dt_ids[] = …; MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids); static int rcar_i2c_probe(struct platform_device *pdev) { … } static void rcar_i2c_remove(struct platform_device *pdev) { … } static int rcar_i2c_suspend(struct device *dev) { … } static int rcar_i2c_resume(struct device *dev) { … } static const struct dev_pm_ops rcar_i2c_pm_ops = …; static struct platform_driver rcar_i2c_driver = …; module_platform_driver(…) …; MODULE_LICENSE(…) …; MODULE_DESCRIPTION(…) …; MODULE_AUTHOR(…) …;
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