From: Carlos Song <carlos.song@xxxxxxx>
Add target mode support for LPI2C.
Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
---
Change for V2:
- remove unused variable ‘lpi2c_imx’ in lpi2c_suspend_noirq.
---
drivers/i2c/busses/i2c-imx-lpi2c.c | 252 ++++++++++++++++++++++++++++-
1 file changed, 248 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 530ca5d76403..73eb04c04466 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -43,6 +43,20 @@
#define LPI2C_MTDR 0x60 /* i2c master TX data register */
#define LPI2C_MRDR 0x70 /* i2c master RX data register */
+#define LPI2C_SCR 0x110 /* i2c target contrl register */
+#define LPI2C_SSR 0x114 /* i2c target status register */
+#define LPI2C_SIER 0x118 /* i2c target interrupt enable */
+#define LPI2C_SDER 0x11C /* i2c target DMA enable */
+#define LPI2C_SCFGR0 0x120 /* i2c target configuration */
+#define LPI2C_SCFGR1 0x124 /* i2c target configuration */
+#define LPI2C_SCFGR2 0x128 /* i2c target configuration */
+#define LPI2C_SAMR 0x140 /* i2c target address match */
+#define LPI2C_SASR 0x150 /* i2c target address status */
+#define LPI2C_STAR 0x154 /* i2c target transmit ACK */
+#define LPI2C_STDR 0x160 /* i2c target transmit data */
+#define LPI2C_SRDR 0x170 /* i2c target receive data */
+#define LPI2C_SRDROR 0x178 /* i2c target receive data read only */
+
/* i2c command */
#define TRAN_DATA 0X00
#define RECV_DATA 0X01
@@ -76,6 +90,42 @@
#define MDER_TDDE BIT(0)
#define MDER_RDDE BIT(1)
+#define SCR_SEN BIT(0)
+#define SCR_RST BIT(1)
+#define SCR_FILTEN BIT(4)
+#define SCR_RTF BIT(8)
+#define SCR_RRF BIT(9)
+#define SCFGR1_RXSTALL BIT(1)
+#define SCFGR1_TXDSTALL BIT(2)
+#define SCFGR2_FILTSDA_SHIFT 24
+#define SCFGR2_FILTSCL_SHIFT 16
+#define SCFGR2_CLKHOLD(x) (x)
+#define SCFGR2_FILTSDA(x) ((x) << SCFGR2_FILTSDA_SHIFT)
+#define SCFGR2_FILTSCL(x) ((x) << SCFGR2_FILTSCL_SHIFT)
+#define SSR_TDF BIT(0)
+#define SSR_RDF BIT(1)
+#define SSR_AVF BIT(2)
+#define SSR_TAF BIT(3)
+#define SSR_RSF BIT(8)
+#define SSR_SDF BIT(9)
+#define SSR_BEF BIT(10)
+#define SSR_FEF BIT(11)
+#define SSR_SBF BIT(24)
+#define SSR_BBF BIT(25)
+#define SSR_CLEAR_BITS (SSR_RSF | SSR_SDF | SSR_BEF | SSR_FEF)
+#define SIER_TDIE BIT(0)
+#define SIER_RDIE BIT(1)
+#define SIER_AVIE BIT(2)
+#define SIER_TAIE BIT(3)
+#define SIER_RSIE BIT(8)
+#define SIER_SDIE BIT(9)
+#define SIER_BEIE BIT(10)
+#define SIER_FEIE BIT(11)
+#define SIER_AM0F BIT(12)
+#define SASR_READ_REQ 0x1
+#define SLAVE_INT_FLAG (SIER_TDIE | SIER_RDIE | SIER_AVIE | \
+ SIER_SDIE | SIER_BEIE)
+
#define I2C_CLK_RATIO 2
#define CHUNK_DATA 256
@@ -133,6 +183,7 @@ struct lpi2c_imx_struct {
struct i2c_bus_recovery_info rinfo;
bool can_use_dma;
struct lpi2c_imx_dma *dma;
+ struct i2c_client *target;
};
static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
@@ -952,9 +1003,57 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
return (result < 0) ? result : num;
}
-static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
+static irqreturn_t lpi2c_imx_target_isr(struct lpi2c_imx_struct *lpi2c_imx,
+ u32 ssr, u32 sier_filter)
+{
+ u8 value;
+ u32 sasr;
+
+ /* Arbitration lost */
+ if (sier_filter & SSR_BEF) {
+ writel(0, lpi2c_imx->base + LPI2C_SIER);
+ return IRQ_HANDLED;
+ }
+
+ /* Address detected */
+ if (sier_filter & SSR_AVF) {
+ sasr = readl(lpi2c_imx->base + LPI2C_SASR);
+ if (SASR_READ_REQ & sasr) {
+ /* Read request */
+ i2c_slave_event(lpi2c_imx->target, I2C_SLAVE_READ_REQUESTED, &value);
+ writel(value, lpi2c_imx->base + LPI2C_STDR);
+ goto ret;
+ } else {
+ /* Write request */
+ i2c_slave_event(lpi2c_imx->target, I2C_SLAVE_WRITE_REQUESTED, &value);
+ }
+ }
+
+ if (sier_filter & SSR_SDF) {
+ /* STOP */
+ i2c_slave_event(lpi2c_imx->target, I2C_SLAVE_STOP, &value);
+ }
+
+ if (sier_filter & SSR_TDF) {
+ /* Target send data */
+ i2c_slave_event(lpi2c_imx->target, I2C_SLAVE_READ_PROCESSED, &value);
+ writel(value, lpi2c_imx->base + LPI2C_STDR);
+ }
+
+ if (sier_filter & SSR_RDF) {
+ /* Target receive data */
+ value = readl(lpi2c_imx->base + LPI2C_SRDR);
+ i2c_slave_event(lpi2c_imx->target, I2C_SLAVE_WRITE_RECEIVED, &value);
+ }
+
+ret:
+ /* Clear SSR */
+ writel(ssr & SSR_CLEAR_BITS, lpi2c_imx->base + LPI2C_SSR);
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t lpi2c_imx_master_isr(struct lpi2c_imx_struct *lpi2c_imx)
{
- struct lpi2c_imx_struct *lpi2c_imx = dev_id;
unsigned int enabled;
unsigned int temp;
@@ -974,6 +1073,119 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
return IRQ_HANDLED;
}
+static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = dev_id;
+ u32 ssr, sier_filter;
+ unsigned int scr;
+
+ if (lpi2c_imx->target) {
+ scr = readl(lpi2c_imx->base + LPI2C_SCR);
+ ssr = readl(lpi2c_imx->base + LPI2C_SSR);
+ sier_filter = ssr & readl(lpi2c_imx->base + LPI2C_SIER);
+ if ((scr & SCR_SEN) && sier_filter)
+ return lpi2c_imx_target_isr(lpi2c_imx, ssr, sier_filter);
+ else
+ return lpi2c_imx_master_isr(lpi2c_imx);
+ } else {
+ return lpi2c_imx_master_isr(lpi2c_imx);
+ }
+}
+
+static void lpi2c_imx_target_init(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ int temp;
+
+ /* reset target module */
+ writel(SCR_RST, lpi2c_imx->base + LPI2C_SCR);
+ writel(0, lpi2c_imx->base + LPI2C_SCR);
+
+ /* Set target addr */
+ writel((lpi2c_imx->target->addr << 1), lpi2c_imx->base + LPI2C_SAMR);
+
+ writel(SCFGR1_RXSTALL | SCFGR1_TXDSTALL, lpi2c_imx->base + LPI2C_SCFGR1);
+
+ /*
+ * set SCFGR2: FILTSDA, FILTSCL and CLKHOLD
+ *
+ * FILTSCL/FILTSDA can eliminate signal skew. It should generally be
+ * set to the same value and should be set >= 50ns.
+ *
+ * CLKHOLD is only used when clock stretching is enabled, but it will
+ * extend the clock stretching to ensure there is an additional delay
+ * between the target driving SDA and the target releasing the SCL pin.
+ *
+ * CLKHOLD setting is crucial for lpi2c target. When master read data
+ * from target, if there is a delay caused by cpu idle, excessive load,
+ * or other delays between two bytes in one message transmission. so it
+ * will cause a short interval time between the driving SDA signal and
+ * releasing SCL signal. Lpi2c master will mistakenly think it is a stop
+ * signal resulting in an arbitration failure. This issue can be avoided
+ * by setting CLKHOLD.
+ *
+ * In order to ensure lpi2c function normally when the lpi2c speed is as
+ * low as 100kHz, CLKHOLD should be set 3 and it is also compatible with
+ * higher clock frequency like 400kHz and 1MHz.
+ */
+ temp = SCFGR2_FILTSDA(2) | SCFGR2_FILTSCL(2) | SCFGR2_CLKHOLD(3);
+ writel(temp, lpi2c_imx->base + LPI2C_SCFGR2);
+
+ /*
+ * Enable module:
+ * SCR_FILTEN can enable digital filter and output delay counter for LPI2C
+ * target mode. So SCR_FILTEN need be asserted when enable SDA/SCL FILTER
+ * and CLKHOLD.
+ */
+ writel(SCR_SEN | SCR_FILTEN, lpi2c_imx->base + LPI2C_SCR);
+
+ /* Enable interrupt from i2c module */
+ writel(SLAVE_INT_FLAG, lpi2c_imx->base + LPI2C_SIER);
+}
+
+static int lpi2c_imx_reg_target(struct i2c_client *client)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = i2c_get_adapdata(client->adapter);
+ int ret;
+
+ if (lpi2c_imx->target)
+ return -EBUSY;
+
+ lpi2c_imx->target = client;
+
+ ret = pm_runtime_resume_and_get(lpi2c_imx->adapter.dev.parent);
+ if (ret < 0) {
+ dev_err(&lpi2c_imx->adapter.dev, "failed to resume i2c controller");
+ return ret;
+ }
+
+ lpi2c_imx_target_init(lpi2c_imx);
+
+ return 0;
+}
+
+static int lpi2c_imx_unreg_target(struct i2c_client *client)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = i2c_get_adapdata(client->adapter);
+ int ret;
+
+ if (!lpi2c_imx->target)
+ return -EINVAL;
+
+ /* Reset target address. */
+ writel(0, lpi2c_imx->base + LPI2C_SAMR);
+
+ writel(SCR_RST, lpi2c_imx->base + LPI2C_SCR);
+ writel(0, lpi2c_imx->base + LPI2C_SCR);
+
+ lpi2c_imx->target = NULL;
+
+ ret = pm_runtime_put_sync(lpi2c_imx->adapter.dev.parent);
+ if (ret < 0)
+ dev_err(&lpi2c_imx->adapter.dev, "failed to suspend i2c controller");
+
+ return ret;
+}
+
static int lpi2c_imx_init_recovery_info(struct lpi2c_imx_struct *lpi2c_imx,
struct platform_device *pdev)
{
@@ -1049,6 +1261,8 @@ static u32 lpi2c_imx_func(struct i2c_adapter *adapter)
static const struct i2c_algorithm lpi2c_imx_algo = {
.master_xfer = lpi2c_imx_xfer,
.functionality = lpi2c_imx_func,
+ .reg_slave = lpi2c_imx_reg_target,
+ .unreg_slave = lpi2c_imx_unreg_target,
};
static const struct of_device_id lpi2c_imx_of_match[] = {
@@ -1199,9 +1413,39 @@ static int __maybe_unused lpi2c_runtime_resume(struct device *dev)
return 0;
}
+static int lpi2c_suspend_noirq(struct device *dev)
+{
+ int ret;
+
+ ret = pm_runtime_force_suspend(dev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int lpi2c_resume_noirq(struct device *dev)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = dev_get_drvdata(dev);
+ int ret;
+
+ ret = pm_runtime_force_resume(dev);
+ if (ret)
+ return ret;
+
+ /*
+ * If i2c module powered down in system suspend, register
+ * value will lose. So reinit target when system resume.
+ */
+ if (lpi2c_imx->target)
+ lpi2c_imx_target_init(lpi2c_imx);
+
+ return 0;
+}
+
static const struct dev_pm_ops lpi2c_pm_ops = {
- SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
- pm_runtime_force_resume)
+ SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(lpi2c_suspend_noirq,
+ lpi2c_resume_noirq)
SET_RUNTIME_PM_OPS(lpi2c_runtime_suspend,
lpi2c_runtime_resume, NULL)
};
--
2.34.1
