[PATCH 12/25] i2c: Add lpi2c support
Sascha Hauer
s.hauer at pengutronix.de
Fri Nov 10 04:57:47 PST 2023
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
drivers/i2c/busses/Kconfig | 7 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-imx-lpi2c.c | 518 +++++++++++++++++++++++++++++
3 files changed, 526 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-imx-lpi2c.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 766aa5edfa..a274baf4b6 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -30,6 +30,13 @@ config I2C_IMX
for many i.MX ARM based SoCs, for MPC85xx and MPC5200 PowerPC based
SoCs.
+config I2C_IMX_LPI2C
+ tristate "IMX Low Power I2C interface"
+ depends on ARCH_IMX || COMPILE_TEST
+ help
+ Say Y here if you want to use the Low Power IIC bus controller
+ on the Freescale i.MX processors.
+
config I2C_DESIGNWARE
bool "Synopsys DesignWare I2C Master driver"
help
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index a1ab46fb28..48f9b5be04 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -4,6 +4,7 @@ obj-$(CONFIG_I2C_BCM283X) += i2c-bcm283x.o
obj-$(CONFIG_I2C_GPIO) += i2c-gpio.o
obj-$(CONFIG_I2C_IMX) += i2c-imx.o
lwl-$(CONFIG_I2C_IMX_EARLY) += i2c-imx-early.o
+obj-$(CONFIG_I2C_IMX_LPI2C) += i2c-imx-lpi2c.o
obj-$(CONFIG_I2C_MV64XXX) += i2c-mv64xxx.o
obj-$(CONFIG_I2C_OMAP) += i2c-omap.o
obj-$(CONFIG_I2C_TEGRA) += i2c-tegra.o
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
new file mode 100644
index 0000000000..f28a445601
--- /dev/null
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * This is i.MX low power i2c controller driver.
+ *
+ * Copyright 2016 Freescale Semiconductor, Inc.
+ */
+
+#include <clock.h>
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <of.h>
+#include <gpio.h>
+#include <malloc.h>
+#include <types.h>
+#include <xfuncs.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <pinctrl.h>
+#include <of_gpio.h>
+#include <of_device.h>
+
+#include <io.h>
+#include <i2c/i2c.h>
+
+#define DRIVER_NAME "imx-lpi2c"
+
+#define LPI2C_PARAM 0x04 /* i2c RX/TX FIFO size */
+#define LPI2C_MCR 0x10 /* i2c contrl register */
+#define LPI2C_MSR 0x14 /* i2c status register */
+#define LPI2C_MIER 0x18 /* i2c interrupt enable */
+#define LPI2C_MCFGR0 0x20 /* i2c master configuration */
+#define LPI2C_MCFGR1 0x24 /* i2c master configuration */
+#define LPI2C_MCFGR2 0x28 /* i2c master configuration */
+#define LPI2C_MCFGR3 0x2C /* i2c master configuration */
+#define LPI2C_MCCR0 0x48 /* i2c master clk configuration */
+#define LPI2C_MCCR1 0x50 /* i2c master clk configuration */
+#define LPI2C_MFCR 0x58 /* i2c master FIFO control */
+#define LPI2C_MFSR 0x5C /* i2c master FIFO status */
+#define LPI2C_MTDR 0x60 /* i2c master TX data register */
+#define LPI2C_MRDR 0x70 /* i2c master RX data register */
+
+/* i2c command */
+#define TRAN_DATA 0X00
+#define RECV_DATA 0X01
+#define GEN_STOP 0X02
+#define RECV_DISCARD 0X03
+#define GEN_START 0X04
+#define START_NACK 0X05
+#define START_HIGH 0X06
+#define START_HIGH_NACK 0X07
+
+#define MCR_MEN BIT(0)
+#define MCR_RST BIT(1)
+#define MCR_DOZEN BIT(2)
+#define MCR_DBGEN BIT(3)
+#define MCR_RTF BIT(8)
+#define MCR_RRF BIT(9)
+#define MSR_TDF BIT(0)
+#define MSR_RDF BIT(1)
+#define MSR_SDF BIT(9)
+#define MSR_NDF BIT(10)
+#define MSR_ALF BIT(11)
+#define MSR_MBF BIT(24)
+#define MSR_BBF BIT(25)
+#define MIER_TDIE BIT(0)
+#define MIER_RDIE BIT(1)
+#define MIER_SDIE BIT(9)
+#define MIER_NDIE BIT(10)
+#define MCFGR1_AUTOSTOP BIT(8)
+#define MCFGR1_IGNACK BIT(9)
+#define MRDR_RXEMPTY BIT(14)
+
+#define I2C_CLK_RATIO 2
+#define CHUNK_DATA 256
+
+#define I2C_PM_TIMEOUT 10 /* ms */
+
+enum lpi2c_imx_mode {
+ STANDARD, /* 100+Kbps */
+ FAST, /* 400+Kbps */
+ FAST_PLUS, /* 1.0+Mbps */
+ HS, /* 3.4+Mbps */
+ ULTRA_FAST, /* 5.0+Mbps */
+};
+
+enum lpi2c_imx_pincfg {
+ TWO_PIN_OD,
+ TWO_PIN_OO,
+ TWO_PIN_PP,
+ FOUR_PIN_PP,
+};
+
+struct lpi2c_imx_struct {
+ struct i2c_adapter adapter;
+ int num_clks;
+ struct clk_bulk_data *clks;
+ void __iomem *base;
+ __u8 *rx_buf;
+ __u8 *tx_buf;
+ unsigned int msglen;
+ unsigned int delivered;
+ unsigned int bitrate;
+ unsigned int txfifosize;
+ unsigned int rxfifosize;
+ enum lpi2c_imx_mode mode;
+};
+
+static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
+ unsigned int enable)
+{
+ writel(enable, lpi2c_imx->base + LPI2C_MIER);
+}
+
+static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int temp;
+ u64 start = get_time_ns();
+
+ while (1) {
+ temp = readl(lpi2c_imx->base + LPI2C_MSR);
+
+ /* check for arbitration lost, clear if set */
+ if (temp & (MSR_ALF | MSR_NDF)) {
+ writel(temp, lpi2c_imx->base + LPI2C_MSR);
+ return -EAGAIN;
+ }
+
+ if (temp & (MSR_BBF | MSR_MBF))
+ break;
+
+ if (is_timeout(start, 500 * MSECOND)) {
+ dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
+ return -ETIMEDOUT;
+ }
+ }
+
+ return 0;
+}
+
+static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int bitrate = lpi2c_imx->bitrate;
+ enum lpi2c_imx_mode mode;
+
+ if (bitrate < I2C_MAX_FAST_MODE_FREQ)
+ mode = STANDARD;
+ else if (bitrate < I2C_MAX_FAST_MODE_PLUS_FREQ)
+ mode = FAST;
+ else if (bitrate < I2C_MAX_HIGH_SPEED_MODE_FREQ)
+ mode = FAST_PLUS;
+ else if (bitrate < I2C_MAX_ULTRA_FAST_MODE_FREQ)
+ mode = HS;
+ else
+ mode = ULTRA_FAST;
+
+ lpi2c_imx->mode = mode;
+}
+
+static int lpi2c_imx_start(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msgs)
+{
+ unsigned int temp;
+
+ temp = readl(lpi2c_imx->base + LPI2C_MCR);
+ temp |= MCR_RRF | MCR_RTF;
+ writel(temp, lpi2c_imx->base + LPI2C_MCR);
+ writel(0x7f00, lpi2c_imx->base + LPI2C_MSR);
+
+ temp = i2c_8bit_addr_from_msg(msgs) | (GEN_START << 8);
+ writel(temp, lpi2c_imx->base + LPI2C_MTDR);
+
+ return lpi2c_imx_bus_busy(lpi2c_imx);
+}
+
+static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int temp;
+ u64 start = get_time_ns();
+
+ writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
+
+ do {
+ temp = readl(lpi2c_imx->base + LPI2C_MSR);
+ if (temp & MSR_SDF)
+ break;
+
+ if (is_timeout(start, 500 * MSECOND)) {
+ dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
+ break;
+ }
+
+ } while (1);
+}
+
+/* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
+static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ u8 prescale, filt, sethold, datavd;
+ unsigned int clk_rate, clk_cycle, clkhi, clklo;
+ enum lpi2c_imx_pincfg pincfg;
+ unsigned int temp;
+
+ lpi2c_imx_set_mode(lpi2c_imx);
+
+ clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk);
+ if (!clk_rate)
+ return -EINVAL;
+
+ if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST)
+ filt = 0;
+ else
+ filt = 2;
+
+ for (prescale = 0; prescale <= 7; prescale++) {
+ clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate)
+ - 3 - (filt >> 1);
+ clkhi = DIV_ROUND_UP(clk_cycle, I2C_CLK_RATIO + 1);
+ clklo = clk_cycle - clkhi;
+ if (clklo < 64)
+ break;
+ }
+
+ if (prescale > 7)
+ return -EINVAL;
+
+ /* set MCFGR1: PINCFG, PRESCALE, IGNACK */
+ if (lpi2c_imx->mode == ULTRA_FAST)
+ pincfg = TWO_PIN_OO;
+ else
+ pincfg = TWO_PIN_OD;
+ temp = prescale | pincfg << 24;
+
+ if (lpi2c_imx->mode == ULTRA_FAST)
+ temp |= MCFGR1_IGNACK;
+
+ writel(temp, lpi2c_imx->base + LPI2C_MCFGR1);
+
+ /* set MCFGR2: FILTSDA, FILTSCL */
+ temp = (filt << 16) | (filt << 24);
+ writel(temp, lpi2c_imx->base + LPI2C_MCFGR2);
+
+ /* set MCCR: DATAVD, SETHOLD, CLKHI, CLKLO */
+ sethold = clkhi;
+ datavd = clkhi >> 1;
+ temp = datavd << 24 | sethold << 16 | clkhi << 8 | clklo;
+
+ if (lpi2c_imx->mode == HS)
+ writel(temp, lpi2c_imx->base + LPI2C_MCCR1);
+ else
+ writel(temp, lpi2c_imx->base + LPI2C_MCCR0);
+
+ return 0;
+}
+
+static int lpi2c_imx_master_enable(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int temp;
+ int ret;
+
+ temp = MCR_RST;
+ writel(temp, lpi2c_imx->base + LPI2C_MCR);
+ writel(0, lpi2c_imx->base + LPI2C_MCR);
+
+ ret = lpi2c_imx_config(lpi2c_imx);
+ if (ret)
+ return ret;
+
+ temp = readl(lpi2c_imx->base + LPI2C_MCR);
+ temp |= MCR_MEN;
+ writel(temp, lpi2c_imx->base + LPI2C_MCR);
+
+ return 0;
+}
+
+static int lpi2c_imx_master_disable(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ u32 temp;
+
+ temp = readl(lpi2c_imx->base + LPI2C_MCR);
+ temp &= ~MCR_MEN;
+ writel(temp, lpi2c_imx->base + LPI2C_MCR);
+
+ return 0;
+}
+
+static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ u32 txcnt;
+ u64 start = get_time_ns();
+
+ do {
+ txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
+
+ if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) {
+ dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n");
+ return -EIO;
+ }
+
+ if (is_timeout(start, 500 * MSECOND)) {
+ dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ } while (txcnt);
+
+ return 0;
+}
+
+static void lpi2c_imx_set_tx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ writel(lpi2c_imx->txfifosize >> 1, lpi2c_imx->base + LPI2C_MFCR);
+}
+
+static void lpi2c_imx_set_rx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int temp, remaining;
+
+ remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;
+
+ if (remaining > (lpi2c_imx->rxfifosize >> 1))
+ temp = lpi2c_imx->rxfifosize >> 1;
+ else
+ temp = 0;
+
+ writel(temp << 16, lpi2c_imx->base + LPI2C_MFCR);
+}
+
+static int lpi2c_imx_write_txfifo(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int data, remaining;
+ uint64_t start = get_time_ns();
+
+ do {
+ u32 cnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
+ if (cnt == lpi2c_imx->txfifosize) {
+ if (is_timeout(start, 100 * MSECOND))
+ return -EIO;
+ continue;
+ }
+
+ data = lpi2c_imx->tx_buf[lpi2c_imx->delivered++];
+
+ writel(data, lpi2c_imx->base + LPI2C_MTDR);
+ remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;
+ } while (remaining);
+
+ return 0;
+}
+
+static int lpi2c_imx_read_rxfifo(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ unsigned int remaining;
+ unsigned int data;
+ uint64_t start = get_time_ns();
+
+ do {
+ data = readl(lpi2c_imx->base + LPI2C_MRDR);
+ if (data & MRDR_RXEMPTY) {
+ if (is_timeout(start, 100 * MSECOND))
+ return -EIO;
+ continue;
+ }
+
+ lpi2c_imx->rx_buf[lpi2c_imx->delivered++] = data & 0xff;
+
+ remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;
+ } while (remaining);
+
+ return 0;
+}
+
+static int lpi2c_imx_write(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msgs)
+{
+ lpi2c_imx->tx_buf = msgs->buf;
+ lpi2c_imx_set_tx_watermark(lpi2c_imx);
+
+ return lpi2c_imx_write_txfifo(lpi2c_imx);
+}
+
+static int lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msgs)
+{
+ unsigned int temp;
+
+ lpi2c_imx->rx_buf = msgs->buf;
+
+ lpi2c_imx_set_rx_watermark(lpi2c_imx);
+ temp = msgs->len > CHUNK_DATA ? CHUNK_DATA - 1 : msgs->len - 1;
+ temp |= (RECV_DATA << 8);
+ writel(temp, lpi2c_imx->base + LPI2C_MTDR);
+
+ lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE);
+
+ return lpi2c_imx_read_rxfifo(lpi2c_imx);
+}
+
+static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
+ struct i2c_msg *msgs, int num)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = container_of(adapter, struct lpi2c_imx_struct, adapter);
+ unsigned int temp;
+ int i, result;
+
+ result = lpi2c_imx_master_enable(lpi2c_imx);
+ if (result)
+ return result;
+
+ for (i = 0; i < num; i++) {
+ result = lpi2c_imx_start(lpi2c_imx, &msgs[i]);
+ if (result)
+ goto disable;
+
+ /* quick smbus */
+ if (num == 1 && msgs[0].len == 0)
+ goto stop;
+
+ lpi2c_imx->rx_buf = NULL;
+ lpi2c_imx->tx_buf = NULL;
+ lpi2c_imx->delivered = 0;
+ lpi2c_imx->msglen = msgs[i].len;
+
+ if (msgs[i].flags & I2C_M_RD)
+ result = lpi2c_imx_read(lpi2c_imx, &msgs[i]);
+ else
+ result = lpi2c_imx_write(lpi2c_imx, &msgs[i]);
+
+ if (result)
+ goto stop;
+
+ if (!(msgs[i].flags & I2C_M_RD)) {
+ result = lpi2c_imx_txfifo_empty(lpi2c_imx);
+ if (result)
+ goto stop;
+ }
+ }
+
+stop:
+ lpi2c_imx_stop(lpi2c_imx);
+
+ temp = readl(lpi2c_imx->base + LPI2C_MSR);
+ if ((temp & MSR_NDF) && !result)
+ result = -EIO;
+
+disable:
+ lpi2c_imx_master_disable(lpi2c_imx);
+
+ dev_dbg(&lpi2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
+ (result < 0) ? "error" : "success msg",
+ (result < 0) ? result : num);
+
+ return (result < 0) ? result : num;
+}
+
+static const struct of_device_id lpi2c_imx_of_match[] = {
+ { .compatible = "fsl,imx7ulp-lpi2c" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, lpi2c_imx_of_match);
+
+static int lpi2c_imx_probe(struct device *dev)
+{
+ struct lpi2c_imx_struct *lpi2c_imx;
+ struct resource *iores;
+ unsigned int temp;
+ int ret;
+
+ lpi2c_imx = xzalloc(sizeof(*lpi2c_imx));
+
+ iores = dev_request_mem_resource(dev, 0);
+ if (IS_ERR(iores))
+ return PTR_ERR(iores);
+
+ lpi2c_imx->base = IOMEM(iores->start);
+
+ lpi2c_imx->adapter.nr = -1;
+ lpi2c_imx->adapter.master_xfer = lpi2c_imx_xfer;
+ lpi2c_imx->adapter.dev.parent = dev;
+ lpi2c_imx->adapter.dev.of_node = dev->of_node;
+
+ ret = clk_bulk_get_all(dev, &lpi2c_imx->clks);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "can't get I2C peripheral clock\n");
+ lpi2c_imx->num_clks = ret;
+
+ ret = of_property_read_u32(dev->of_node,
+ "clock-frequency", &lpi2c_imx->bitrate);
+ if (ret)
+ lpi2c_imx->bitrate = I2C_MAX_STANDARD_MODE_FREQ;
+
+ ret = clk_bulk_enable(lpi2c_imx->num_clks, lpi2c_imx->clks);
+ if (ret)
+ return ret;
+
+ temp = readl(lpi2c_imx->base + LPI2C_PARAM);
+ lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
+ lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);
+
+ ret = i2c_add_numbered_adapter(&lpi2c_imx->adapter);
+ if (ret)
+ return ret;
+
+ dev_dbg(&lpi2c_imx->adapter.dev, "LPI2C adapter registered\n");
+
+ return 0;
+}
+
+static struct driver lpi2c_imx_driver = {
+ .probe = lpi2c_imx_probe,
+ .name = "i2c-fsl",
+ .of_compatible = DRV_OF_COMPAT(lpi2c_imx_of_match),
+};
+coredevice_platform_driver(lpi2c_imx_driver);
+
+MODULE_AUTHOR("Gao Pan <pandy.gao at nxp.com>");
+MODULE_DESCRIPTION("I2C adapter driver for LPI2C bus");
+MODULE_LICENSE("GPL");
--
2.39.2
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