diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-rcar.c')
-rw-r--r-- | drivers/i2c/busses/i2c-rcar.c | 64 |
1 files changed, 47 insertions, 17 deletions
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 254e6219e538..a7578f6da979 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -2,8 +2,8 @@ /* * Driver for the Renesas R-Car I2C unit * - * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com> - * Copyright (C) 2011-2015 Renesas Electronics Corporation + * Copyright (C) 2014-19 Wolfram Sang <wsa@sang-engineering.com> + * Copyright (C) 2011-2019 Renesas Electronics Corporation * * Copyright (C) 2012-14 Renesas Solutions Corp. * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> @@ -39,8 +39,8 @@ #define ICSAR 0x1C /* slave address */ #define ICMAR 0x20 /* master address */ #define ICRXTX 0x24 /* data port */ -#define ICDMAER 0x3c /* DMA enable */ -#define ICFBSCR 0x38 /* first bit setup cycle */ +#define ICFBSCR 0x38 /* first bit setup cycle (Gen3) */ +#define ICDMAER 0x3c /* DMA enable (Gen3) */ /* ICSCR */ #define SDBS (1 << 3) /* slave data buffer select */ @@ -83,7 +83,6 @@ #define TMDMAE (1 << 0) /* DMA Master Transmitted Enable */ /* ICFBSCR */ -#define TCYC06 0x04 /* 6*Tcyc delay 1st bit between SDA and SCL */ #define TCYC17 0x0f /* 17*Tcyc delay 1st bit between SDA and SCL */ @@ -212,6 +211,10 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv) rcar_i2c_write(priv, ICMSR, 0); /* start clock */ rcar_i2c_write(priv, ICCCR, priv->icccr); + + if (priv->devtype == I2C_RCAR_GEN3) + rcar_i2c_write(priv, ICFBSCR, TCYC17); + } static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) @@ -355,20 +358,11 @@ static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv) rcar_i2c_prepare_msg(priv); } -/* - * interrupt functions - */ static void rcar_i2c_dma_unmap(struct rcar_i2c_priv *priv) { struct dma_chan *chan = priv->dma_direction == DMA_FROM_DEVICE ? priv->dma_rx : priv->dma_tx; - /* Disable DMA Master Received/Transmitted */ - rcar_i2c_write(priv, ICDMAER, 0); - - /* Reset default delay */ - rcar_i2c_write(priv, ICFBSCR, TCYC06); - dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg), sg_dma_len(&priv->sg), priv->dma_direction); @@ -378,6 +372,9 @@ static void rcar_i2c_dma_unmap(struct rcar_i2c_priv *priv) priv->flags |= ID_P_NO_RXDMA; priv->dma_direction = DMA_NONE; + + /* Disable DMA Master Received/Transmitted, must be last! */ + rcar_i2c_write(priv, ICDMAER, 0); } static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv) @@ -464,9 +461,6 @@ static void rcar_i2c_dma(struct rcar_i2c_priv *priv) return; } - /* Set delay for DMA operations */ - rcar_i2c_write(priv, ICFBSCR, TCYC17); - /* Enable DMA Master Received/Transmitted */ if (read) rcar_i2c_write(priv, ICDMAER, RMDMAE); @@ -617,6 +611,15 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv) return true; } +/* + * 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 clear RCAR_BUS_MASK_DATA bits 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. + */ static irqreturn_t rcar_i2c_irq(int irq, void *ptr) { struct rcar_i2c_priv *priv = ptr; @@ -1017,10 +1020,37 @@ static int rcar_i2c_remove(struct platform_device *pdev) return 0; } +#ifdef CONFIG_PM_SLEEP +static int rcar_i2c_suspend(struct device *dev) +{ + struct rcar_i2c_priv *priv = dev_get_drvdata(dev); + + i2c_mark_adapter_suspended(&priv->adap); + return 0; +} + +static int rcar_i2c_resume(struct device *dev) +{ + struct rcar_i2c_priv *priv = dev_get_drvdata(dev); + + i2c_mark_adapter_resumed(&priv->adap); + return 0; +} + +static const struct dev_pm_ops rcar_i2c_pm_ops = { + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rcar_i2c_suspend, rcar_i2c_resume) +}; + +#define DEV_PM_OPS (&rcar_i2c_pm_ops) +#else +#define DEV_PM_OPS NULL +#endif /* CONFIG_PM_SLEEP */ + static struct platform_driver rcar_i2c_driver = { .driver = { .name = "i2c-rcar", .of_match_table = rcar_i2c_dt_ids, + .pm = DEV_PM_OPS, }, .probe = rcar_i2c_probe, .remove = rcar_i2c_remove, |