Commit 7d4c57ab authored by Théo Lebrun's avatar Théo Lebrun Committed by Andi Shyti
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i2c: nomadik: support Mobileye EyeQ5 I2C controller 



Add compatible for the integration of the same DB8500 IP block into the
Mobileye EyeQ5 platform. Two quirks are present:

 - The memory bus only supports 32-bit accesses. Avoid writeb() and
   readb() by introducing helper functions that fallback to writel()
   and readl().

 - A register must be configured for the I2C speed mode; it is located
   in a shared register region called OLB. We access that memory region
   using a syscon & regmap that gets passed as a phandle (mobileye,olb).

   A two-bit enum per controller is written into the register; that
   requires us to know the global index of the I2C controller (cell arg
   to the mobileye,olb phandle).

We add #include <linux/mfd/syscon.h> and <linux/regmap.h>.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarThéo Lebrun <theo.lebrun@bootlin.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarAndi Shyti <andi.shyti@kernel.org>
parent ec189b9f

drivers/i2c/busses/i2c-nomadik.c

+86 −4
Original line number Diff line number Diff line
@@ -6,6 +6,12 @@ 
 * I2C master mode controller driver, used in Nomadik 8815

 * and Ux500 platforms.

 *

 * The Mobileye EyeQ5 platform is also supported; it uses

 * the same Ux500/DB8500 IP block with two quirks:

 *  - The memory bus only supports 32-bit accesses.

 *  - A register must be configured for the I2C speed mode;

 *    it is located in a shared register region called OLB.

 *

 * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>

 * Author: Sachin Verma <sachin.verma@st.com>

 */
@@ -22,6 +28,8 @@ 
#include <linux/pm_runtime.h>

#include <linux/of.h>

#include <linux/pinctrl/consumer.h>

#include <linux/mfd/syscon.h>

#include <linux/regmap.h>



#define DRIVER_NAME "nmk-i2c"
@@ -110,6 +118,15 @@ enum i2c_freq_mode { 
	I2C_FREQ_MODE_FAST_PLUS,	/* up to 1 Mb/s */

};



/* Mobileye EyeQ5 offset into a shared register region (called OLB) */

#define NMK_I2C_EYEQ5_OLB_IOCR2			0x0B8



enum i2c_eyeq5_speed {

	I2C_EYEQ5_SPEED_FAST,

	I2C_EYEQ5_SPEED_FAST_PLUS,

	I2C_EYEQ5_SPEED_HIGH_SPEED,

};



/**

 * struct i2c_vendor_data - per-vendor variations

 * @has_mtdws: variant has the MTDWS bit
@@ -174,6 +191,7 @@ struct i2c_nmk_client { 
 * @xfer_wq: xfer done wait queue.

 * @xfer_done: xfer done boolean.

 * @result: controller propogated result.

 * @has_32b_bus: controller is on a bus that only supports 32-bit accesses.

 */

struct nmk_i2c_dev {

	struct i2c_vendor_data		*vendor;
@@ -192,6 +210,7 @@ struct nmk_i2c_dev { 
	struct wait_queue_head		xfer_wq;

	bool				xfer_done;

	int				result;

	bool				has_32b_bus;

};



/* controller's abort causes */
@@ -215,6 +234,24 @@ static inline void i2c_clr_bit(void __iomem *reg, u32 mask) 
	writel(readl(reg) & ~mask, reg);

}



static inline u8 nmk_i2c_readb(const struct nmk_i2c_dev *priv,

			       unsigned long reg)

{

	if (priv->has_32b_bus)

		return readl(priv->virtbase + reg);

	else

		return readb(priv->virtbase + reg);

}



static inline void nmk_i2c_writeb(const struct nmk_i2c_dev *priv, u32 val,

				  unsigned long reg)

{

	if (priv->has_32b_bus)

		writel(val, priv->virtbase + reg);

	else

		writeb(val, priv->virtbase + reg);

}



/**

 * flush_i2c_fifo() - This function flushes the I2C FIFO

 * @priv: private data of I2C Driver
@@ -523,7 +560,7 @@ static void fill_tx_fifo(struct nmk_i2c_dev *priv, int no_bytes) 
			(priv->cli.count != 0);

			count--) {

		/* write to the Tx FIFO */

		writeb(*priv->cli.buffer, priv->virtbase + I2C_TFR);

		nmk_i2c_writeb(priv, *priv->cli.buffer, I2C_TFR);

		priv->cli.buffer++;

		priv->cli.count--;

		priv->cli.xfer_bytes++;
@@ -792,7 +829,7 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg) 
	case I2C_IT_RXFNF:

		for (count = rft; count > 0; count--) {

			/* Read the Rx FIFO */

			*priv->cli.buffer = readb(priv->virtbase + I2C_RFR);

			*priv->cli.buffer = nmk_i2c_readb(priv, I2C_RFR);

			priv->cli.buffer++;

		}

		priv->cli.count -= rft;
@@ -802,7 +839,7 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg) 
	/* Rx FIFO full */

	case I2C_IT_RXFF:

		for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) {

			*priv->cli.buffer = readb(priv->virtbase + I2C_RFR);

			*priv->cli.buffer = nmk_i2c_readb(priv, I2C_RFR);

			priv->cli.buffer++;

		}

		priv->cli.count -= MAX_I2C_FIFO_THRESHOLD;
@@ -818,7 +855,7 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg) 
				if (priv->cli.count == 0)

					break;

				*priv->cli.buffer =

					readb(priv->virtbase + I2C_RFR);

					nmk_i2c_readb(priv, I2C_RFR);

				priv->cli.buffer++;

				priv->cli.count--;

				priv->cli.xfer_bytes++;
@@ -996,6 +1033,44 @@ static void nmk_i2c_of_probe(struct device_node *np, 
		priv->timeout_usecs = 200 * USEC_PER_MSEC;

}



static const unsigned int nmk_i2c_eyeq5_masks[] = {

	GENMASK(5, 4),

	GENMASK(7, 6),

	GENMASK(9, 8),

	GENMASK(11, 10),

	GENMASK(13, 12),

};



static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)

{

	struct device *dev = &priv->adev->dev;

	struct device_node *np = dev->of_node;

	unsigned int mask, speed_mode;

	struct regmap *olb;

	unsigned int id;



	priv->has_32b_bus = true;



	olb = syscon_regmap_lookup_by_phandle_args(np, "mobileye,olb", 1, &id);

	if (IS_ERR(olb))

		return PTR_ERR(olb);

	if (id >= ARRAY_SIZE(nmk_i2c_eyeq5_masks))

		return -ENOENT;



	if (priv->clk_freq <= 400000)

		speed_mode = I2C_EYEQ5_SPEED_FAST;

	else if (priv->clk_freq <= 1000000)

		speed_mode = I2C_EYEQ5_SPEED_FAST_PLUS;

	else

		speed_mode = I2C_EYEQ5_SPEED_HIGH_SPEED;



	mask = nmk_i2c_eyeq5_masks[id];

	regmap_update_bits(olb, NMK_I2C_EYEQ5_OLB_IOCR2,

			   mask, speed_mode << __fls(mask));



	return 0;

}



static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)

{

	int ret = 0;
@@ -1012,8 +1087,15 @@ static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id) 


	priv->vendor = vendor;

	priv->adev = adev;

	priv->has_32b_bus = false;

	nmk_i2c_of_probe(np, priv);



	if (of_device_is_compatible(np, "mobileye,eyeq5-i2c")) {

		ret = nmk_i2c_eyeq5_probe(priv);

		if (ret)

			return dev_err_probe(dev, ret, "failed OLB lookup\n");

	}



	if (priv->tft > max_fifo_threshold) {

		dev_warn(dev, "requested TX FIFO threshold %u, adjusted down to %u\n",

			 priv->tft, max_fifo_threshold);