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Message-Id: <20210530225659.17138-1-chris.packham@alliedtelesis.co.nz>
Date: Mon, 31 May 2021 10:56:59 +1200
From: Chris Packham <chris.packham@...iedtelesis.co.nz>
To: wsa@...nel.org, rjui@...adcom.com, sbranden@...adcom.com,
bcm-kernel-feedback-list@...adcom.com
Cc: linux-i2c@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Richard Laing <richard.laing@...iedtelesis.co.nz>,
Chris Packham <chris.packham@...iedtelesis.co.nz>
Subject: [PATCH] i2c: bcm-iproc: Add i2c recovery support
From: Richard Laing <richard.laing@...iedtelesis.co.nz>
The bcm-iproc controller can put the SDA/SCL lines into bit-bang mode,
make use of this to support i2c bus recovery.
Signed-off-by: Richard Laing <richard.laing@...iedtelesis.co.nz>
Signed-off-by: Chris Packham <chris.packham@...iedtelesis.co.nz>
---
Notes:
Richard did most of the work on this. I'm just cleaning it up to get it
upstream.
drivers/i2c/busses/i2c-bcm-iproc.c | 115 +++++++++++++++++++++++++++++
1 file changed, 115 insertions(+)
diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c
index cceaf69279a9..d63a286c1660 100644
--- a/drivers/i2c/busses/i2c-bcm-iproc.c
+++ b/drivers/i2c/busses/i2c-bcm-iproc.c
@@ -26,6 +26,7 @@
#define CFG_RESET_SHIFT 31
#define CFG_EN_SHIFT 30
#define CFG_SLAVE_ADDR_0_SHIFT 28
+#define CFG_BIT_BANG_SHIFT 29
#define CFG_M_RETRY_CNT_SHIFT 16
#define CFG_M_RETRY_CNT_MASK 0x0f
@@ -66,6 +67,12 @@
#define S_FIFO_RX_THLD_SHIFT 8
#define S_FIFO_RX_THLD_MASK 0x3f
+#define M_BB_CTRL_OFFSET 0x14
+#define M_BB_SMBCLK_IN 31
+#define M_BB_SMBCLK_OUT_EN 30
+#define M_BB_SMBDAT_IN 29
+#define M_BB_SMBDAT_OUT_EN 28
+
#define M_CMD_OFFSET 0x30
#define M_CMD_START_BUSY_SHIFT 31
#define M_CMD_STATUS_SHIFT 25
@@ -713,6 +720,112 @@ static void bcm_iproc_i2c_enable_disable(struct bcm_iproc_i2c_dev *iproc_i2c,
iproc_i2c_wr_reg(iproc_i2c, CFG_OFFSET, val);
}
+static void bcm_iproc_i2c_reset(struct bcm_iproc_i2c_dev *iproc_i2c)
+{
+ u32 tmp;
+
+ tmp = readl(iproc_i2c->base + CFG_OFFSET);
+ tmp |= BIT(CFG_RESET_SHIFT);
+ writel(tmp, iproc_i2c->base + CFG_OFFSET);
+ udelay(100);
+
+}
+
+static void bcm_iproc_i2c_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ dev_dbg(iproc_i2c->device, "Prepare recovery\n");
+
+ /* Disable interrupts */
+ writel(0, iproc_i2c->base + IE_OFFSET);
+ readl(iproc_i2c->base + IE_OFFSET);
+ synchronize_irq(iproc_i2c->irq);
+
+ bcm_iproc_i2c_reset(iproc_i2c);
+
+ /* Switch to bit-bang mode */
+ tmp = readl(iproc_i2c->base + CFG_OFFSET);
+ tmp |= BIT(CFG_BIT_BANG_SHIFT);
+ writel(tmp, iproc_i2c->base + CFG_OFFSET);
+}
+
+static void bcm_iproc_i2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ /* Switch to normal mode */
+ tmp = readl(iproc_i2c->base + CFG_OFFSET);
+ tmp &= ~BIT(CFG_BIT_BANG_SHIFT);
+ writel(tmp, iproc_i2c->base + CFG_OFFSET);
+ udelay(100);
+
+ bcm_iproc_i2c_init(iproc_i2c);
+ bcm_iproc_i2c_enable_disable(iproc_i2c, true);
+
+ dev_dbg(iproc_i2c->device, "Recovery complete\n");
+}
+
+static int bcm_iproc_i2c_get_scl(struct i2c_adapter *adap)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ tmp = readl(iproc_i2c->base + M_BB_CTRL_OFFSET);
+
+ return !!(tmp & BIT(M_BB_SMBCLK_IN));
+}
+
+static void bcm_iproc_i2c_set_scl(struct i2c_adapter *adap, int val)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ tmp = readl(iproc_i2c->base + M_BB_CTRL_OFFSET);
+ if (val)
+ tmp |= BIT(M_BB_SMBCLK_OUT_EN);
+ else
+ tmp &= ~BIT(M_BB_SMBCLK_OUT_EN);
+
+ writel(tmp, iproc_i2c->base + M_BB_CTRL_OFFSET);
+}
+
+static void bcm_iproc_i2c_set_sda(struct i2c_adapter *adap, int val)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ tmp = readl(iproc_i2c->base + M_BB_CTRL_OFFSET);
+ if (val)
+ tmp |= BIT(M_BB_SMBDAT_OUT_EN);
+ else
+ tmp &= ~BIT(M_BB_SMBDAT_OUT_EN);
+
+ writel(tmp, iproc_i2c->base + M_BB_CTRL_OFFSET);
+}
+
+static int bcm_iproc_i2c_get_sda(struct i2c_adapter *adap)
+{
+ struct bcm_iproc_i2c_dev *iproc_i2c = i2c_get_adapdata(adap);
+ u32 tmp;
+
+ tmp = readl(iproc_i2c->base + M_BB_CTRL_OFFSET);
+
+ return !!(tmp & BIT(M_BB_SMBDAT_IN));
+}
+
+static struct i2c_bus_recovery_info bcm_iproc_recovery_info = {
+ .recover_bus = i2c_generic_scl_recovery,
+ .prepare_recovery = bcm_iproc_i2c_prepare_recovery,
+ .unprepare_recovery = bcm_iproc_i2c_unprepare_recovery,
+ .set_scl = bcm_iproc_i2c_set_scl,
+ .get_scl = bcm_iproc_i2c_get_scl,
+ .set_sda = bcm_iproc_i2c_set_sda,
+ .get_sda = bcm_iproc_i2c_get_sda,
+};
+
static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *iproc_i2c,
struct i2c_msg *msg)
{
@@ -839,6 +952,7 @@ static int bcm_iproc_i2c_xfer_internal(struct bcm_iproc_i2c_dev *iproc_i2c,
if (!!(iproc_i2c_rd_reg(iproc_i2c,
M_CMD_OFFSET) & BIT(M_CMD_START_BUSY_SHIFT))) {
dev_warn(iproc_i2c->device, "bus is busy\n");
+ i2c_recover_bus(&iproc_i2c->adapter);
return -EBUSY;
}
@@ -1111,6 +1225,7 @@ static int bcm_iproc_i2c_probe(struct platform_device *pdev)
of_node_full_name(iproc_i2c->device->of_node));
adap->algo = &bcm_iproc_algo;
adap->quirks = &bcm_iproc_i2c_quirks;
+ adap->bus_recovery_info = &bcm_iproc_recovery_info;
adap->dev.parent = &pdev->dev;
adap->dev.of_node = pdev->dev.of_node;
--
2.31.1
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