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Message-Id: <20240306-mbly-i2c-v3-8-605f866aa4ec@bootlin.com>
Date: Wed, 06 Mar 2024 18:59:28 +0100
From: Théo Lebrun <theo.lebrun@...tlin.com>
To: Linus Walleij <linus.walleij@...aro.org>,
Andi Shyti <andi.shyti@...nel.org>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc: linux-arm-kernel@...ts.infradead.org, linux-i2c@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mips@...r.kernel.org, Gregory Clement <gregory.clement@...tlin.com>,
Vladimir Kondratiev <vladimir.kondratiev@...ileye.com>,
Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
Tawfik Bayouk <tawfik.bayouk@...ileye.com>,
Théo Lebrun <theo.lebrun@...tlin.com>
Subject: [PATCH v3 08/11] 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: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Théo Lebrun <theo.lebrun@...tlin.com>
---
drivers/i2c/busses/i2c-nomadik.c | 90 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 86 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index 2e738b18677e..7d039bd36aa6 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -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@...ricsson.com>
* Author: Sachin Verma <sachin.verma@...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);
--
2.44.0
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