From 5afa9d35782890e8fbd972f12ee5183ba5feb81d Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Mon, 6 Jun 2011 11:25:19 -0600 Subject: i2c: tegra: Assign unused slave address On Tegra, we should always use the "new" I2C slave controller, to avoid issues with the old controller. This was implemented in commit 65a1a0a "i2c: tegra: Enable new slave mode." There is currently no driver for the Tegra I2C slave controller upstream. Additionally, the controller cannot be completely disabled. Instead, we need to: a) Set I2C_SL_CNFG_NACK to make the controller automatically NACK any incoming transactions. b) The controller's definition of NACK isn't identical to the I2C protocol's definition. Specifically, it will perform a standard NACK, but *also* continue to hold the clock line low in expectation of receiving more data. This can hang the bus, or at least cause transaction timeouts, if something starts a transaction that matches the controller's slave address. Since the default address is 0x00, the general call address, this does occur in practice. To avoid this, we explicitly program a slave address that is reserved for future expansion. For current boards, this guarantees the address will never be used. If a future board ever needs to use this address, we can add platform data to determine a board-specific safe address. 0xfc is picked by this patch. This patch is based on a change previously posted by: Wei Ni http://www.spinics.net/lists/linux-i2c/msg05437.html In turned based on internal changes by: Bharat Nihalani A semantically equivalent change has been contained in the various ChromeOS kernels for a while. I tested this change on top of 3.0-rc2 on Harmony, and interacted with the WM8903 I2C-based audio codec. Signed-off-by: Stephen Warren Signed-off-by: Ben Dooks diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 4d93196..fb3b4f8 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -40,8 +40,10 @@ #define I2C_CNFG_NEW_MASTER_FSM (1<<11) #define I2C_STATUS 0x01C #define I2C_SL_CNFG 0x020 +#define I2C_SL_CNFG_NACK (1<<1) #define I2C_SL_CNFG_NEWSL (1<<2) #define I2C_SL_ADDR1 0x02c +#define I2C_SL_ADDR2 0x030 #define I2C_TX_FIFO 0x050 #define I2C_RX_FIFO 0x054 #define I2C_PACKET_TRANSFER_STATUS 0x058 @@ -337,7 +339,11 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) if (!i2c_dev->is_dvc) { u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG); - i2c_writel(i2c_dev, sl_cfg | I2C_SL_CNFG_NEWSL, I2C_SL_CNFG); + sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL; + i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG); + i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1); + i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2); + } val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT | -- cgit v0.10.2 From 19820510c504d5ba572959c67a72d913afc187a6 Mon Sep 17 00:00:00 2001 From: Huisung Kang Date: Thu, 23 Jun 2011 21:37:33 +0900 Subject: i2c-s3c2410: Fix typo 'i2s' -> 'i2c' Signed-off-by: Huisung Kang Signed-off-by: Kukjin Kim Signed-off-by: Ben Dooks diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 6c00c10..9ad1850 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -248,12 +248,12 @@ static inline int is_msgend(struct s3c24xx_i2c *i2c) return i2c->msg_ptr >= i2c->msg->len; } -/* i2s_s3c_irq_nextbyte +/* i2c_s3c_irq_nextbyte * * process an interrupt and work out what to do */ -static int i2s_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) +static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) { unsigned long tmp; unsigned char byte; @@ -444,7 +444,7 @@ static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id) /* pretty much this leaves us with the fact that we've * transmitted or received whatever byte we last sent */ - i2s_s3c_irq_nextbyte(i2c, status); + i2c_s3c_irq_nextbyte(i2c, status); out: return IRQ_HANDLED; -- cgit v0.10.2 From b90ea76542c53300d39e76f72cf583cd0e0b1f68 Mon Sep 17 00:00:00 2001 From: Jonghwan Choi Date: Thu, 23 Jun 2011 21:37:20 +0900 Subject: i2c-s3c2410: Remove useless break code Signed-off-by: Jonghwan Choi Signed-off-by: Kukjin Kim Signed-off-by: Ben Dooks diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 9ad1850..f84a63c 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -264,7 +264,6 @@ static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat) case STATE_IDLE: dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__); goto out; - break; case STATE_STOP: dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__); -- cgit v0.10.2