* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
@ 2014-09-29 9:32 Anders Berg
2014-09-29 10:07 ` Varka Bhadram
2014-10-03 10:36 ` Wolfram Sang
0 siblings, 2 replies; 9+ messages in thread
From: Anders Berg @ 2014-09-29 9:32 UTC (permalink / raw)
To: linux-arm-kernel
Add I2C bus driver for the controller found in the LSI Axxia family SoCs. The
driver implements 10-bit addressing and SMBus transfer modes via emulation
(including SMBus block data read).
Signed-off-by: Anders Berg <anders.berg@avagotech.com>
---
Changelog
v2:
- Document the len <= 255 limitation
- return IRQ_HANDLED on unexpected IRQs
- fixed a number of style issues
- handle zero-length messages
- use reinit_completion() where appropriate
- enable for COMPILE_TEST
.../devicetree/bindings/i2c/i2c-axxia.txt | 30 ++
drivers/i2c/busses/Kconfig | 11 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-axxia.c | 561 +++++++++++++++++++++
4 files changed, 603 insertions(+)
create mode 100644 Documentation/devicetree/bindings/i2c/i2c-axxia.txt
create mode 100644 drivers/i2c/busses/i2c-axxia.c
diff --git a/Documentation/devicetree/bindings/i2c/i2c-axxia.txt b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt
new file mode 100644
index 0000000..2296d78
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt
@@ -0,0 +1,30 @@
+LSI Axxia I2C
+
+Required properties :
+- compatible : Must be "lsi,api2c"
+- reg : Offset and length of the register set for the device
+- interrupts : the interrupt specifier
+- #address-cells : Must be <1>;
+- #size-cells : Must be <0>;
+- clock-names : Must contain "i2c".
+- clocks: Must contain an entry for each name in clock-names. See the common
+ clock bindings.
+
+Optional properties :
+- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
+ the default 100 kHz frequency will be used. As only Normal and Fast modes
+ are supported, possible values are 100000 and 400000.
+
+Example :
+
+i2c at 02010084000 {
+ compatible = "lsi,api2c";
+ device_type = "i2c";
+ #address-cells = <1>;
+ #size-cells = <0>;
+ reg = <0x20 0x10084000 0x00 0x1000>;
+ interrupts = <0 19 4>;
+ clocks = <&clk_per>;
+ clock-names = "i2c";
+ clock-frequency = <400000>;
+};
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 2ac87fa..8983474 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -77,6 +77,17 @@ config I2C_AMD8111
This driver can also be built as a module. If so, the module
will be called i2c-amd8111.
+config I2C_AXXIA
+ tristate "Axxia I2C controller"
+ depends on ARCH_AXXIA || COMPILE_TEST
+ default ARCH_AXXIA
+ help
+ Say yes if you want to support the I2C bus on Axxia platforms.
+
+ Please note that this controller is limited to transfers of maximum
+ 255 bytes in length. Any attempt to to a larger transfer will return
+ an error.
+
config I2C_I801
tristate "Intel 82801 (ICH/PCH)"
depends on PCI
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 49bf07e..5899edb 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o
obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o
obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o
obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o
+obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
obj-$(CONFIG_I2C_I801) += i2c-i801.o
obj-$(CONFIG_I2C_ISCH) += i2c-isch.o
obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o
diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
new file mode 100644
index 0000000..c6faca1
--- /dev/null
+++ b/drivers/i2c/busses/i2c-axxia.c
@@ -0,0 +1,561 @@
+/*
+ * This driver implements I2C master functionality using the LSI API2C
+ * controller.
+ *
+ * NOTE: The controller has a limitation in that it can only do transfers of
+ * maximum 255 bytes at a time. If a larger transfer is attempted, error code
+ * (-EINVAL) is returned.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#define SCL_WAIT_TIMEOUT_NS 25000000
+#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
+#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
+#define FIFO_SIZE 8
+
+#define GLOBAL_CONTROL 0x00
+#define GLOBAL_MST_EN BIT(0)
+#define GLOBAL_SLV_EN BIT(1)
+#define GLOBAL_IBML_EN BIT(2)
+#define INTERRUPT_STATUS 0x04
+#define INTERRUPT_ENABLE 0x08
+#define INT_SLV BIT(1)
+#define INT_MST BIT(0)
+#define WAIT_TIMER_CONTROL 0x0c
+#define WT_EN BIT(15)
+#define WT_VALUE(_x) ((_x) & 0x7fff)
+#define IBML_TIMEOUT 0x10
+#define IBML_LOW_MEXT 0x14
+#define IBML_LOW_SEXT 0x18
+#define TIMER_CLOCK_DIV 0x1c
+#define I2C_BUS_MONITOR 0x20
+#define SOFT_RESET 0x24
+#define MST_COMMAND 0x28
+#define CMD_BUSY (1<<3)
+#define CMD_MANUAL (0x00 | CMD_BUSY)
+#define CMD_AUTO (0x01 | CMD_BUSY)
+#define MST_RX_XFER 0x2c
+#define MST_TX_XFER 0x30
+#define MST_ADDR_1 0x34
+#define MST_ADDR_2 0x38
+#define MST_DATA 0x3c
+#define MST_TX_FIFO 0x40
+#define MST_RX_FIFO 0x44
+#define MST_INT_ENABLE 0x48
+#define MST_INT_STATUS 0x4c
+#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
+#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
+#define MST_STATUS_SNS (1 << 11) /* Manual mode done */
+#define MST_STATUS_SS (1 << 10) /* Automatic mode done */
+#define MST_STATUS_SCC (1 << 9) /* Stop complete */
+#define MST_STATUS_IP (1 << 8) /* Invalid parameter */
+#define MST_STATUS_TSS (1 << 7) /* Timeout */
+#define MST_STATUS_AL (1 << 6) /* Arbitration lost */
+#define MST_STATUS_ND (1 << 5) /* NAK on data phase */
+#define MST_STATUS_NA (1 << 4) /* NAK on address phase */
+#define MST_STATUS_NAK (MST_STATUS_NA | \
+ MST_STATUS_ND)
+#define MST_STATUS_ERR (MST_STATUS_NAK | \
+ MST_STATUS_AL | \
+ MST_STATUS_IP | \
+ MST_STATUS_TSS)
+#define MST_TX_BYTES_XFRD 0x50
+#define MST_RX_BYTES_XFRD 0x54
+#define SCL_HIGH_PERIOD 0x80
+#define SCL_LOW_PERIOD 0x84
+#define SPIKE_FLTR_LEN 0x88
+#define SDA_SETUP_TIME 0x8c
+#define SDA_HOLD_TIME 0x90
+
+/**
+ * axxia_i2c_dev - I2C device context
+ * @base: pointer to register struct
+ * @msg: pointer to current message
+ * @msg_xfrd: number of bytes transferred in msg
+ * @msg_err: error code for completed message
+ * @msg_complete: xfer completion object
+ * @dev: device reference
+ * @adapter: core i2c abstraction
+ * @i2c_clk: clock reference for i2c input clock
+ * @bus_clk_rate: current i2c bus clock rate
+ */
+struct axxia_i2c_dev {
+ void __iomem *base;
+ struct i2c_msg *msg;
+ size_t msg_xfrd;
+ int msg_err;
+ struct completion msg_complete;
+ struct device *dev;
+ struct i2c_adapter adapter;
+ struct clk *i2c_clk;
+ u32 bus_clk_rate;
+};
+
+static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
+{
+ u32 int_en;
+
+ int_en = readl(idev->base + MST_INT_ENABLE);
+ writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
+}
+
+static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
+{
+ u32 int_en;
+
+ int_en = readl(idev->base + MST_INT_ENABLE);
+ writel(int_en | mask, idev->base + MST_INT_ENABLE);
+}
+
+/**
+ * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
+ */
+static u32 ns_to_clk(u64 ns, u32 clk_mhz)
+{
+ return div_u64(ns * clk_mhz, 1000);
+}
+
+static int axxia_i2c_init(struct axxia_i2c_dev *idev)
+{
+ u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
+ u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
+ u32 t_setup;
+ u32 t_high, t_low;
+ u32 tmo_clk;
+ u32 prescale;
+ unsigned long timeout;
+
+ dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
+ idev->bus_clk_rate, clk_mhz, divisor);
+
+ /* Reset controller */
+ writel(0x01, idev->base + SOFT_RESET);
+ timeout = jiffies + msecs_to_jiffies(100);
+ while (readl(idev->base + SOFT_RESET) & 1) {
+ if (time_after(jiffies, timeout)) {
+ dev_warn(idev->dev, "Soft reset failed\n");
+ break;
+ }
+ }
+
+ /* Enable Master Mode */
+ writel(0x1, idev->base + GLOBAL_CONTROL);
+
+ if (idev->bus_clk_rate <= 100000) {
+ /* Standard mode SCL 50/50, tSU:DAT = 250 ns */
+ t_high = divisor * 1 / 2;
+ t_low = divisor * 1 / 2;
+ t_setup = ns_to_clk(250, clk_mhz);
+ } else {
+ /* Fast mode SCL 33/66, tSU:DAT = 100 ns */
+ t_high = divisor * 1 / 3;
+ t_low = divisor * 2 / 3;
+ t_setup = ns_to_clk(100, clk_mhz);
+ }
+
+ /* SCL High Time */
+ writel(t_high, idev->base + SCL_HIGH_PERIOD);
+ /* SCL Low Time */
+ writel(t_low, idev->base + SCL_LOW_PERIOD);
+ /* SDA Setup Time */
+ writel(t_setup, idev->base + SDA_SETUP_TIME);
+ /* SDA Hold Time, 300ns */
+ writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
+ /* Filter <50ns spikes */
+ writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
+
+ /* Configure Time-Out Registers */
+ tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
+
+ /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
+ for (prescale = 0; prescale < 15; ++prescale) {
+ if (tmo_clk <= 0x7fff)
+ break;
+ tmo_clk >>= 1;
+ }
+ if (tmo_clk > 0x7fff)
+ tmo_clk = 0x7fff;
+
+ /* Prescale divider (log2) */
+ writel(prescale, idev->base + TIMER_CLOCK_DIV);
+ /* Timeout in divided clocks */
+ writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
+
+ /* Mask all master interrupt bits */
+ i2c_int_disable(idev, ~0);
+
+ /* Interrupt enable */
+ writel(0x01, idev->base + INTERRUPT_ENABLE);
+
+ return 0;
+}
+
+static int i2c_m_rd(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_RD) != 0;
+}
+
+static int i2c_m_ten(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_TEN) != 0;
+}
+
+static int i2c_m_recv_len(const struct i2c_msg *msg)
+{
+ return (msg->flags & I2C_M_RECV_LEN) != 0;
+}
+
+/**
+ * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
+ * transfer length if this is the first byte of such a transfer.
+ */
+static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
+{
+ struct i2c_msg *msg = idev->msg;
+ size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
+ int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
+
+ while (bytes_to_transfer-- > 0) {
+ int c = readl(idev->base + MST_DATA);
+
+ if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
+ /*
+ * Check length byte for SMBus block read
+ */
+ if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
+ idev->msg_err = -EPROTO;
+ i2c_int_disable(idev, ~0);
+ complete(&idev->msg_complete);
+ break;
+ }
+ msg->len = 1 + c;
+ writel(msg->len, idev->base + MST_RX_XFER);
+ }
+ msg->buf[idev->msg_xfrd++] = c;
+ }
+
+ return 0;
+}
+
+/**
+ * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
+ * @return: Number of bytes left to transfer.
+ */
+static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
+{
+ struct i2c_msg *msg = idev->msg;
+ size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
+ int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
+ int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
+
+ while (bytes_to_transfer-- > 0)
+ writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
+
+ return ret;
+}
+
+static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
+{
+ struct axxia_i2c_dev *idev = _dev;
+ u32 status;
+
+ if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST))
+ return IRQ_NONE;
+
+ /* Read interrupt status bits */
+ status = readl(idev->base + MST_INT_STATUS);
+
+ if (!idev->msg) {
+ dev_warn(idev->dev, "unexpected interrupt");
+ goto out;
+ }
+
+ /* RX FIFO needs service? */
+ if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
+ axxia_i2c_empty_rx_fifo(idev);
+
+ /* TX FIFO needs service? */
+ if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
+ if (axxia_i2c_fill_tx_fifo(idev) == 0)
+ i2c_int_disable(idev, MST_STATUS_TFL);
+ }
+
+ if (status & MST_STATUS_SCC) {
+ /* Stop completed */
+ i2c_int_disable(idev, ~0);
+ complete(&idev->msg_complete);
+ } else if (status & MST_STATUS_SNS) {
+ /* Transfer done */
+ i2c_int_disable(idev, ~0);
+ if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
+ axxia_i2c_empty_rx_fifo(idev);
+ complete(&idev->msg_complete);
+ } else if (unlikely(status & MST_STATUS_ERR)) {
+ /* Transfer error */
+ i2c_int_disable(idev, ~0);
+ if (status & MST_STATUS_AL)
+ idev->msg_err = -EAGAIN;
+ else if (status & MST_STATUS_NAK)
+ idev->msg_err = -ENXIO;
+ else
+ idev->msg_err = -EIO;
+ dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
+ status,
+ idev->msg->addr,
+ readl(idev->base + MST_RX_BYTES_XFRD),
+ readl(idev->base + MST_RX_XFER),
+ readl(idev->base + MST_TX_BYTES_XFRD),
+ readl(idev->base + MST_TX_XFER));
+ complete(&idev->msg_complete);
+ }
+
+out:
+ /* Clear interrupt */
+ writel(INT_MST, idev->base + INTERRUPT_STATUS);
+
+ return IRQ_HANDLED;
+}
+
+static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
+{
+ u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
+ u32 rx_xfer, tx_xfer;
+ u32 addr_1, addr_2;
+ int ret;
+
+ if (msg->len > 255) {
+ dev_warn(idev->dev, "unsupported length %u\n", msg->len);
+ return -EINVAL;
+ }
+
+ idev->msg = msg;
+ idev->msg_xfrd = 0;
+ idev->msg_err = 0;
+ reinit_completion(&idev->msg_complete);
+
+ if (i2c_m_ten(msg)) {
+ /* 10-bit address
+ * addr_1: 5'b11110 | addr[9:8] | (R/nW)
+ * addr_2: addr[7:0]
+ */
+ addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
+ addr_2 = msg->addr & 0xFF;
+ } else {
+ /* 7-bit address
+ * addr_1: addr[6:0] | (R/nW)
+ * addr_2: dont care
+ */
+ addr_1 = (msg->addr << 1) & 0xFF;
+ addr_2 = 0;
+ }
+
+ if (i2c_m_rd(msg)) {
+ /* I2C read transfer */
+ rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
+ tx_xfer = 0;
+ addr_1 |= 1; /* Set the R/nW bit of the address */
+ } else {
+ /* I2C write transfer */
+ rx_xfer = 0;
+ tx_xfer = msg->len;
+ }
+
+ writel(rx_xfer, idev->base + MST_RX_XFER);
+ writel(tx_xfer, idev->base + MST_TX_XFER);
+ writel(addr_1, idev->base + MST_ADDR_1);
+ writel(addr_2, idev->base + MST_ADDR_2);
+
+ if (i2c_m_rd(msg))
+ int_mask |= MST_STATUS_RFL;
+ else if (axxia_i2c_fill_tx_fifo(idev) != 0)
+ int_mask |= MST_STATUS_TFL;
+
+ /* Start manual mode */
+ writel(CMD_MANUAL, idev->base + MST_COMMAND);
+
+ i2c_int_enable(idev, int_mask);
+
+ ret = wait_for_completion_timeout(&idev->msg_complete,
+ I2C_XFER_TIMEOUT);
+
+ i2c_int_disable(idev, int_mask);
+
+ if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
+ dev_warn(idev->dev, "busy after xfer");
+
+ if (ret == 0)
+ idev->msg_err = -ETIMEDOUT;
+
+ if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
+ axxia_i2c_init(idev);
+
+ return idev->msg_err;
+}
+
+static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
+{
+ u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC;
+ int ret;
+
+ reinit_completion(&idev->msg_complete);
+
+ /* Issue stop */
+ writel(0xb, idev->base + MST_COMMAND);
+ i2c_int_enable(idev, int_mask);
+ ret = wait_for_completion_timeout(&idev->msg_complete,
+ I2C_STOP_TIMEOUT);
+ i2c_int_disable(idev, int_mask);
+ if (ret == 0)
+ return -ETIMEDOUT;
+
+ if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
+ dev_warn(idev->dev, "busy after stop");
+
+ return 0;
+}
+
+static int
+axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+ struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
+ int i;
+ int ret = 0;
+
+ for (i = 0; ret == 0 && i < num; ++i)
+ ret = axxia_i2c_xfer_msg(idev, &msgs[i]);
+
+ axxia_i2c_stop(idev);
+
+ return ret ? : i;
+}
+
+static u32 axxia_i2c_func(struct i2c_adapter *adap)
+{
+ u32 caps = (I2C_FUNC_I2C |
+ I2C_FUNC_10BIT_ADDR |
+ I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
+ return caps;
+}
+
+static const struct i2c_algorithm axxia_i2c_algo = {
+ .master_xfer = axxia_i2c_xfer,
+ .functionality = axxia_i2c_func,
+};
+
+static int axxia_i2c_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct axxia_i2c_dev *idev = NULL;
+ struct resource *res;
+ void __iomem *base;
+ int irq;
+ int ret = 0;
+
+ idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
+ if (!idev)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "missing interrupt resource\n");
+ return irq;
+ }
+
+ idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
+ if (IS_ERR(idev->i2c_clk)) {
+ dev_err(&pdev->dev, "missing clock");
+ return PTR_ERR(idev->i2c_clk);
+ }
+
+ idev->base = base;
+ idev->dev = &pdev->dev;
+ init_completion(&idev->msg_complete);
+
+ of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
+ if (idev->bus_clk_rate == 0)
+ idev->bus_clk_rate = 100000; /* default clock rate */
+
+ ret = axxia_i2c_init(idev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to initialize");
+ return ret;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
+ pdev->name, idev);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
+ return ret;
+ }
+
+ clk_prepare_enable(idev->i2c_clk);
+
+ i2c_set_adapdata(&idev->adapter, idev);
+ strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
+ idev->adapter.owner = THIS_MODULE;
+ idev->adapter.class = I2C_CLASS_HWMON;
+ idev->adapter.algo = &axxia_i2c_algo;
+ idev->adapter.dev.parent = &pdev->dev;
+ idev->adapter.dev.of_node = pdev->dev.of_node;
+
+ platform_set_drvdata(pdev, idev);
+
+ ret = i2c_add_adapter(&idev->adapter);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to add adapter\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int axxia_i2c_remove(struct platform_device *pdev)
+{
+ struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(idev->i2c_clk);
+ i2c_del_adapter(&idev->adapter);
+
+ return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id axxia_i2c_of_match[] = {
+ { .compatible = "lsi,api2c", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
+
+static struct platform_driver axxia_i2c_driver = {
+ .probe = axxia_i2c_probe,
+ .remove = axxia_i2c_remove,
+ .driver = {
+ .name = "axxia-i2c",
+ .of_match_table = axxia_i2c_of_match,
+ },
+};
+
+module_platform_driver(axxia_i2c_driver);
+
+MODULE_DESCRIPTION("Axxia I2C Bus driver");
+MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
+MODULE_LICENSE("GPL v2");
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 9:32 [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx Anders Berg
@ 2014-09-29 10:07 ` Varka Bhadram
2014-09-29 10:13 ` Wolfram Sang
2014-09-29 11:13 ` Anders Berg
2014-10-03 10:36 ` Wolfram Sang
1 sibling, 2 replies; 9+ messages in thread
From: Varka Bhadram @ 2014-09-29 10:07 UTC (permalink / raw)
To: linux-arm-kernel
On 09/29/2014 03:02 PM, Anders Berg wrote:
> Add I2C bus driver for the controller found in the LSI Axxia family SoCs. The
> driver implements 10-bit addressing and SMBus transfer modes via emulation
> (including SMBus block data read).
>
> Signed-off-by: Anders Berg <anders.berg@avagotech.com>
> ---
>
> Changelog
>
> v2:
> - Document the len <= 255 limitation
> - return IRQ_HANDLED on unexpected IRQs
> - fixed a number of style issues
> - handle zero-length messages
> - use reinit_completion() where appropriate
> - enable for COMPILE_TEST
>
> .../devicetree/bindings/i2c/i2c-axxia.txt | 30 ++
> drivers/i2c/busses/Kconfig | 11 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-axxia.c | 561 +++++++++++++++++++++
> 4 files changed, 603 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/i2c/i2c-axxia.txt
> create mode 100644 drivers/i2c/busses/i2c-axxia.c
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-axxia.txt b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt
> new file mode 100644
> index 0000000..2296d78
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-axxia.txt
> @@ -0,0 +1,30 @@
> +LSI Axxia I2C
> +
> +Required properties :
> +- compatible : Must be "lsi,api2c"
> +- reg : Offset and length of the register set for the device
> +- interrupts : the interrupt specifier
> +- #address-cells : Must be <1>;
> +- #size-cells : Must be <0>;
> +- clock-names : Must contain "i2c".
> +- clocks: Must contain an entry for each name in clock-names. See the common
> + clock bindings.
> +
> +Optional properties :
> +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
> + the default 100 kHz frequency will be used. As only Normal and Fast modes
> + are supported, possible values are 100000 and 400000.
> +
> +Example :
> +
> +i2c at 02010084000 {
> + compatible = "lsi,api2c";
> + device_type = "i2c";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + reg = <0x20 0x10084000 0x00 0x1000>;
> + interrupts = <0 19 4>;
> + clocks = <&clk_per>;
> + clock-names = "i2c";
> + clock-frequency = <400000>;
> +};
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 2ac87fa..8983474 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -77,6 +77,17 @@ config I2C_AMD8111
> This driver can also be built as a module. If so, the module
> will be called i2c-amd8111.
>
> +config I2C_AXXIA
> + tristate "Axxia I2C controller"
> + depends on ARCH_AXXIA || COMPILE_TEST
> + default ARCH_AXXIA
> + help
> + Say yes if you want to support the I2C bus on Axxia platforms.
> +
> + Please note that this controller is limited to transfers of maximum
> + 255 bytes in length. Any attempt to to a larger transfer will return
> + an error.
> +
> config I2C_I801
> tristate "Intel 82801 (ICH/PCH)"
> depends on PCI
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 49bf07e..5899edb 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o
> obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o
> obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o
> obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o
> +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
> obj-$(CONFIG_I2C_I801) += i2c-i801.o
> obj-$(CONFIG_I2C_ISCH) += i2c-isch.o
> obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o
> diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
> new file mode 100644
> index 0000000..c6faca1
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-axxia.c
> @@ -0,0 +1,561 @@
> +/*
> + * This driver implements I2C master functionality using the LSI API2C
> + * controller.
> + *
> + * NOTE: The controller has a limitation in that it can only do transfers of
> + * maximum 255 bytes at a time. If a larger transfer is attempted, error code
> + * (-EINVAL) is returned.
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + */
> +#include <linux/clk.h>
> +#include <linux/clkdev.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +
> +#define SCL_WAIT_TIMEOUT_NS 25000000
> +#define I2C_XFER_TIMEOUT (msecs_to_jiffies(250))
> +#define I2C_STOP_TIMEOUT (msecs_to_jiffies(100))
> +#define FIFO_SIZE 8
> +
> +#define GLOBAL_CONTROL 0x00
> +#define GLOBAL_MST_EN BIT(0)
> +#define GLOBAL_SLV_EN BIT(1)
> +#define GLOBAL_IBML_EN BIT(2)
> +#define INTERRUPT_STATUS 0x04
> +#define INTERRUPT_ENABLE 0x08
> +#define INT_SLV BIT(1)
> +#define INT_MST BIT(0)
> +#define WAIT_TIMER_CONTROL 0x0c
> +#define WT_EN BIT(15)
> +#define WT_VALUE(_x) ((_x) & 0x7fff)
> +#define IBML_TIMEOUT 0x10
> +#define IBML_LOW_MEXT 0x14
> +#define IBML_LOW_SEXT 0x18
> +#define TIMER_CLOCK_DIV 0x1c
> +#define I2C_BUS_MONITOR 0x20
> +#define SOFT_RESET 0x24
> +#define MST_COMMAND 0x28
> +#define CMD_BUSY (1<<3)
> +#define CMD_MANUAL (0x00 | CMD_BUSY)
> +#define CMD_AUTO (0x01 | CMD_BUSY)
> +#define MST_RX_XFER 0x2c
> +#define MST_TX_XFER 0x30
> +#define MST_ADDR_1 0x34
> +#define MST_ADDR_2 0x38
> +#define MST_DATA 0x3c
> +#define MST_TX_FIFO 0x40
> +#define MST_RX_FIFO 0x44
> +#define MST_INT_ENABLE 0x48
> +#define MST_INT_STATUS 0x4c
> +#define MST_STATUS_RFL (1 << 13) /* RX FIFO serivce */
> +#define MST_STATUS_TFL (1 << 12) /* TX FIFO service */
> +#define MST_STATUS_SNS (1 << 11) /* Manual mode done */
> +#define MST_STATUS_SS (1 << 10) /* Automatic mode done */
> +#define MST_STATUS_SCC (1 << 9) /* Stop complete */
> +#define MST_STATUS_IP (1 << 8) /* Invalid parameter */
> +#define MST_STATUS_TSS (1 << 7) /* Timeout */
> +#define MST_STATUS_AL (1 << 6) /* Arbitration lost */
> +#define MST_STATUS_ND (1 << 5) /* NAK on data phase */
> +#define MST_STATUS_NA (1 << 4) /* NAK on address phase */
> +#define MST_STATUS_NAK (MST_STATUS_NA | \
> + MST_STATUS_ND)
> +#define MST_STATUS_ERR (MST_STATUS_NAK | \
> + MST_STATUS_AL | \
> + MST_STATUS_IP | \
> + MST_STATUS_TSS)
> +#define MST_TX_BYTES_XFRD 0x50
> +#define MST_RX_BYTES_XFRD 0x54
> +#define SCL_HIGH_PERIOD 0x80
> +#define SCL_LOW_PERIOD 0x84
> +#define SPIKE_FLTR_LEN 0x88
> +#define SDA_SETUP_TIME 0x8c
> +#define SDA_HOLD_TIME 0x90
> +
> +/**
> + * axxia_i2c_dev - I2C device context
> + * @base: pointer to register struct
> + * @msg: pointer to current message
> + * @msg_xfrd: number of bytes transferred in msg
> + * @msg_err: error code for completed message
> + * @msg_complete: xfer completion object
> + * @dev: device reference
> + * @adapter: core i2c abstraction
> + * @i2c_clk: clock reference for i2c input clock
> + * @bus_clk_rate: current i2c bus clock rate
> + */
> +struct axxia_i2c_dev {
> + void __iomem *base;
> + struct i2c_msg *msg;
> + size_t msg_xfrd;
> + int msg_err;
> + struct completion msg_complete;
> + struct device *dev;
> + struct i2c_adapter adapter;
> + struct clk *i2c_clk;
> + u32 bus_clk_rate;
> +};
> +
> +static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
> +{
> + u32 int_en;
> +
> + int_en = readl(idev->base + MST_INT_ENABLE);
> + writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
> +}
> +
> +static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
> +{
> + u32 int_en;
> +
> + int_en = readl(idev->base + MST_INT_ENABLE);
> + writel(int_en | mask, idev->base + MST_INT_ENABLE);
> +}
> +
> +/**
> + * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
> + */
> +static u32 ns_to_clk(u64 ns, u32 clk_mhz)
> +{
> + return div_u64(ns * clk_mhz, 1000);
> +}
> +
> +static int axxia_i2c_init(struct axxia_i2c_dev *idev)
> +{
> + u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
> + u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
> + u32 t_setup;
> + u32 t_high, t_low;
> + u32 tmo_clk;
> + u32 prescale;
> + unsigned long timeout;
> +
> + dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
> + idev->bus_clk_rate, clk_mhz, divisor);
> +
> + /* Reset controller */
> + writel(0x01, idev->base + SOFT_RESET);
> + timeout = jiffies + msecs_to_jiffies(100);
> + while (readl(idev->base + SOFT_RESET) & 1) {
> + if (time_after(jiffies, timeout)) {
> + dev_warn(idev->dev, "Soft reset failed\n");
> + break;
> + }
> + }
> +
> + /* Enable Master Mode */
> + writel(0x1, idev->base + GLOBAL_CONTROL);
> +
> + if (idev->bus_clk_rate <= 100000) {
> + /* Standard mode SCL 50/50, tSU:DAT = 250 ns */
> + t_high = divisor * 1 / 2;
> + t_low = divisor * 1 / 2;
> + t_setup = ns_to_clk(250, clk_mhz);
> + } else {
> + /* Fast mode SCL 33/66, tSU:DAT = 100 ns */
> + t_high = divisor * 1 / 3;
> + t_low = divisor * 2 / 3;
> + t_setup = ns_to_clk(100, clk_mhz);
> + }
> +
> + /* SCL High Time */
> + writel(t_high, idev->base + SCL_HIGH_PERIOD);
> + /* SCL Low Time */
> + writel(t_low, idev->base + SCL_LOW_PERIOD);
> + /* SDA Setup Time */
> + writel(t_setup, idev->base + SDA_SETUP_TIME);
> + /* SDA Hold Time, 300ns */
> + writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
> + /* Filter <50ns spikes */
> + writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
> +
> + /* Configure Time-Out Registers */
> + tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
> +
> + /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
> + for (prescale = 0; prescale < 15; ++prescale) {
> + if (tmo_clk <= 0x7fff)
> + break;
> + tmo_clk >>= 1;
> + }
> + if (tmo_clk > 0x7fff)
> + tmo_clk = 0x7fff;
> +
> + /* Prescale divider (log2) */
> + writel(prescale, idev->base + TIMER_CLOCK_DIV);
> + /* Timeout in divided clocks */
> + writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
> +
> + /* Mask all master interrupt bits */
> + i2c_int_disable(idev, ~0);
> +
> + /* Interrupt enable */
> + writel(0x01, idev->base + INTERRUPT_ENABLE);
> +
> + return 0;
> +}
> +
> +static int i2c_m_rd(const struct i2c_msg *msg)
> +{
> + return (msg->flags & I2C_M_RD) != 0;
> +}
> +
> +static int i2c_m_ten(const struct i2c_msg *msg)
> +{
> + return (msg->flags & I2C_M_TEN) != 0;
> +}
> +
> +static int i2c_m_recv_len(const struct i2c_msg *msg)
> +{
> + return (msg->flags & I2C_M_RECV_LEN) != 0;
> +}
> +
> +/**
> + * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
> + * transfer length if this is the first byte of such a transfer.
> + */
> +static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
> +{
> + struct i2c_msg *msg = idev->msg;
> + size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
> + int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd);
> +
> + while (bytes_to_transfer-- > 0) {
> + int c = readl(idev->base + MST_DATA);
> +
> + if (idev->msg_xfrd == 0 && i2c_m_recv_len(msg)) {
> + /*
> + * Check length byte for SMBus block read
> + */
> + if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
> + idev->msg_err = -EPROTO;
> + i2c_int_disable(idev, ~0);
> + complete(&idev->msg_complete);
> + break;
> + }
> + msg->len = 1 + c;
> + writel(msg->len, idev->base + MST_RX_XFER);
> + }
> + msg->buf[idev->msg_xfrd++] = c;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
> + * @return: Number of bytes left to transfer.
> + */
> +static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
> +{
> + struct i2c_msg *msg = idev->msg;
> + size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
> + int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
> + int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
> +
> + while (bytes_to_transfer-- > 0)
> + writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
> +
> + return ret;
> +}
> +
> +static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
> +{
> + struct axxia_i2c_dev *idev = _dev;
> + u32 status;
> +
> + if (!(readl(idev->base + INTERRUPT_STATUS) & INT_MST))
> + return IRQ_NONE;
> +
> + /* Read interrupt status bits */
> + status = readl(idev->base + MST_INT_STATUS);
> +
> + if (!idev->msg) {
> + dev_warn(idev->dev, "unexpected interrupt");
Missed terminating new line '\n'
> + goto out;
> + }
> +
> + /* RX FIFO needs service? */
> + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
> + axxia_i2c_empty_rx_fifo(idev);
> +
> + /* TX FIFO needs service? */
> + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
> + if (axxia_i2c_fill_tx_fifo(idev) == 0)
> + i2c_int_disable(idev, MST_STATUS_TFL);
> + }
> +
> + if (status & MST_STATUS_SCC) {
> + /* Stop completed */
> + i2c_int_disable(idev, ~0);
> + complete(&idev->msg_complete);
> + } else if (status & MST_STATUS_SNS) {
> + /* Transfer done */
> + i2c_int_disable(idev, ~0);
> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
> + axxia_i2c_empty_rx_fifo(idev);
> + complete(&idev->msg_complete);
> + } else if (unlikely(status & MST_STATUS_ERR)) {
> + /* Transfer error */
> + i2c_int_disable(idev, ~0);
> + if (status & MST_STATUS_AL)
> + idev->msg_err = -EAGAIN;
> + else if (status & MST_STATUS_NAK)
> + idev->msg_err = -ENXIO;
> + else
> + idev->msg_err = -EIO;
> + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
> + status,
> + idev->msg->addr,
> + readl(idev->base + MST_RX_BYTES_XFRD),
> + readl(idev->base + MST_RX_XFER),
> + readl(idev->base + MST_TX_BYTES_XFRD),
> + readl(idev->base + MST_TX_XFER));
> + complete(&idev->msg_complete);
> + }
> +
> +out:
> + /* Clear interrupt */
> + writel(INT_MST, idev->base + INTERRUPT_STATUS);
> +
> + return IRQ_HANDLED;
> +}
> +
Its looks good if we move the entire ISR above probe/remove functionalities...
> +static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
> +{
> + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SNS;
> + u32 rx_xfer, tx_xfer;
> + u32 addr_1, addr_2;
> + int ret;
> +
> + if (msg->len > 255) {
> + dev_warn(idev->dev, "unsupported length %u\n", msg->len);
> + return -EINVAL;
> + }
> +
> + idev->msg = msg;
> + idev->msg_xfrd = 0;
> + idev->msg_err = 0;
> + reinit_completion(&idev->msg_complete);
> +
> + if (i2c_m_ten(msg)) {
> + /* 10-bit address
> + * addr_1: 5'b11110 | addr[9:8] | (R/nW)
> + * addr_2: addr[7:0]
> + */
> + addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
> + addr_2 = msg->addr & 0xFF;
> + } else {
> + /* 7-bit address
> + * addr_1: addr[6:0] | (R/nW)
> + * addr_2: dont care
> + */
> + addr_1 = (msg->addr << 1) & 0xFF;
> + addr_2 = 0;
> + }
> +
> + if (i2c_m_rd(msg)) {
> + /* I2C read transfer */
> + rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
> + tx_xfer = 0;
> + addr_1 |= 1; /* Set the R/nW bit of the address */
> + } else {
> + /* I2C write transfer */
> + rx_xfer = 0;
> + tx_xfer = msg->len;
> + }
> +
> + writel(rx_xfer, idev->base + MST_RX_XFER);
> + writel(tx_xfer, idev->base + MST_TX_XFER);
> + writel(addr_1, idev->base + MST_ADDR_1);
> + writel(addr_2, idev->base + MST_ADDR_2);
> +
> + if (i2c_m_rd(msg))
> + int_mask |= MST_STATUS_RFL;
> + else if (axxia_i2c_fill_tx_fifo(idev) != 0)
> + int_mask |= MST_STATUS_TFL;
> +
> + /* Start manual mode */
> + writel(CMD_MANUAL, idev->base + MST_COMMAND);
> +
> + i2c_int_enable(idev, int_mask);
> +
> + ret = wait_for_completion_timeout(&idev->msg_complete,
> + I2C_XFER_TIMEOUT);
> +
> + i2c_int_disable(idev, int_mask);
> +
> + if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
> + dev_warn(idev->dev, "busy after xfer");
'\n'
> +
> + if (ret == 0)
> + idev->msg_err = -ETIMEDOUT;
> +
> + if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
> + axxia_i2c_init(idev);
> +
> + return idev->msg_err;
> +}
> +
> +static int axxia_i2c_stop(struct axxia_i2c_dev *idev)
> +{
> + u32 int_mask = MST_STATUS_ERR | MST_STATUS_SCC;
> + int ret;
> +
> + reinit_completion(&idev->msg_complete);
> +
> + /* Issue stop */
> + writel(0xb, idev->base + MST_COMMAND);
> + i2c_int_enable(idev, int_mask);
> + ret = wait_for_completion_timeout(&idev->msg_complete,
> + I2C_STOP_TIMEOUT);
> + i2c_int_disable(idev, int_mask);
> + if (ret == 0)
> + return -ETIMEDOUT;
> +
> + if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
> + dev_warn(idev->dev, "busy after stop");
'\n'
> +
> + return 0;
> +}
> +
> +static int
> +axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> +{
> + struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
> + int i;
> + int ret = 0;
> +
> + for (i = 0; ret == 0 && i < num; ++i)
> + ret = axxia_i2c_xfer_msg(idev, &msgs[i]);
> +
> + axxia_i2c_stop(idev);
> +
> + return ret ? : i;
> +}
> +
> +static u32 axxia_i2c_func(struct i2c_adapter *adap)
> +{
> + u32 caps = (I2C_FUNC_I2C |
> + I2C_FUNC_10BIT_ADDR |
> + I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
> + return caps;
return (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
> +}
> +
> +static const struct i2c_algorithm axxia_i2c_algo = {
> + .master_xfer = axxia_i2c_xfer,
> + .functionality = axxia_i2c_func,
> +};
> +
> +static int axxia_i2c_probe(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct axxia_i2c_dev *idev = NULL;
> + struct resource *res;
> + void __iomem *base;
> + int irq;
> + int ret = 0;
> +
> + idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
> + if (!idev)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
Error checking on *res*...?
We should *return* on platform_get_resource() failure..
> + base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "missing interrupt resource\n");
> + return irq;
> + }
> +
> + idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
> + if (IS_ERR(idev->i2c_clk)) {
> + dev_err(&pdev->dev, "missing clock");
Missed terminating new line '\n'
> + return PTR_ERR(idev->i2c_clk);
> + }
> +
> + idev->base = base;
> + idev->dev = &pdev->dev;
> + init_completion(&idev->msg_complete);
> +
> + of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
> + if (idev->bus_clk_rate == 0)
> + idev->bus_clk_rate = 100000; /* default clock rate */
> +
> + ret = axxia_i2c_init(idev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to initialize");
Missed terminating new line '\n'
> + return ret;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
> + pdev->name, idev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
> + return ret;
> + }
> +
> + clk_prepare_enable(idev->i2c_clk);
> +
> + i2c_set_adapdata(&idev->adapter, idev);
> + strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
> + idev->adapter.owner = THIS_MODULE;
> + idev->adapter.class = I2C_CLASS_HWMON;
> + idev->adapter.algo = &axxia_i2c_algo;
> + idev->adapter.dev.parent = &pdev->dev;
> + idev->adapter.dev.of_node = pdev->dev.of_node;
> +
> + platform_set_drvdata(pdev, idev);
> +
> + ret = i2c_add_adapter(&idev->adapter);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to add adapter\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int axxia_i2c_remove(struct platform_device *pdev)
> +{
> + struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
> +
> + clk_disable_unprepare(idev->i2c_clk);
> + i2c_del_adapter(&idev->adapter);
> +
> + return 0;
> +}
> +
> +/* Match table for of_platform binding */
> +static const struct of_device_id axxia_i2c_of_match[] = {
> + { .compatible = "lsi,api2c", },
> + {},
> +};
> +
> +MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
> +
> +static struct platform_driver axxia_i2c_driver = {
> + .probe = axxia_i2c_probe,
> + .remove = axxia_i2c_remove,
> + .driver = {
> + .name = "axxia-i2c",
> + .of_match_table = axxia_i2c_of_match,
> + },
> +};
> +
> +module_platform_driver(axxia_i2c_driver);
> +
> +MODULE_DESCRIPTION("Axxia I2C Bus driver");
> +MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
> +MODULE_LICENSE("GPL v2");
--
Regards,
Varka Bhadram.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 10:13 ` Wolfram Sang
@ 2014-09-29 10:13 ` Varka Bhadram
0 siblings, 0 replies; 9+ messages in thread
From: Varka Bhadram @ 2014-09-29 10:13 UTC (permalink / raw)
To: linux-arm-kernel
On 09/29/2014 03:43 PM, Wolfram Sang wrote:
>>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> Error checking on *res*...?
>>
>> We should *return* on platform_get_resource() failure..
>>
>>> + base = devm_ioremap_resource(&pdev->dev, res);
> Nope. devm_ioremap_resource does that.
>
Yes it will [1]. Thanks for the clarification.
[1]:http://lxr.free-electrons.com/source/lib/devres.c#L117
--
Regards,
Varka Bhadram.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 10:07 ` Varka Bhadram
@ 2014-09-29 10:13 ` Wolfram Sang
2014-09-29 10:13 ` Varka Bhadram
2014-09-29 11:13 ` Anders Berg
1 sibling, 1 reply; 9+ messages in thread
From: Wolfram Sang @ 2014-09-29 10:13 UTC (permalink / raw)
To: linux-arm-kernel
> >+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>
> Error checking on *res*...?
>
> We should *return* on platform_get_resource() failure..
>
> >+ base = devm_ioremap_resource(&pdev->dev, res);
Nope. devm_ioremap_resource does that.
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^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 10:07 ` Varka Bhadram
2014-09-29 10:13 ` Wolfram Sang
@ 2014-09-29 11:13 ` Anders Berg
2014-09-29 11:14 ` Varka Bhadram
1 sibling, 1 reply; 9+ messages in thread
From: Anders Berg @ 2014-09-29 11:13 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Sep 29, 2014 at 12:07 PM, Varka Bhadram <varkabhadram@gmail.com> wrote:
> On 09/29/2014 03:02 PM, Anders Berg wrote:
>>
>> Add I2C bus driver for the controller found in the LSI Axxia family SoCs.
>> The
>> driver implements 10-bit addressing and SMBus transfer modes via emulation
>> (including SMBus block data read).
>>
>> Signed-off-by: Anders Berg <anders.berg@avagotech.com>
>> ---
>>
(...)
>> +
>> + if (!idev->msg) {
>> + dev_warn(idev->dev, "unexpected interrupt");
>
>
> Missed terminating new line '\n'
>
Right, I'll fix that (all occurrences)
>
>> + goto out;
>> + }
>> +
>> + /* RX FIFO needs service? */
>> + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
>> + axxia_i2c_empty_rx_fifo(idev);
>> +
>> + /* TX FIFO needs service? */
>> + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
>> + if (axxia_i2c_fill_tx_fifo(idev) == 0)
>> + i2c_int_disable(idev, MST_STATUS_TFL);
>> + }
>> +
>> + if (status & MST_STATUS_SCC) {
>> + /* Stop completed */
>> + i2c_int_disable(idev, ~0);
>> + complete(&idev->msg_complete);
>> + } else if (status & MST_STATUS_SNS) {
>> + /* Transfer done */
>> + i2c_int_disable(idev, ~0);
>> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd <
>> idev->msg->len)
>> + axxia_i2c_empty_rx_fifo(idev);
>> + complete(&idev->msg_complete);
>> + } else if (unlikely(status & MST_STATUS_ERR)) {
>> + /* Transfer error */
>> + i2c_int_disable(idev, ~0);
>> + if (status & MST_STATUS_AL)
>> + idev->msg_err = -EAGAIN;
>> + else if (status & MST_STATUS_NAK)
>> + idev->msg_err = -ENXIO;
>> + else
>> + idev->msg_err = -EIO;
>> + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u
>> tx=%u/%u\n",
>> + status,
>> + idev->msg->addr,
>> + readl(idev->base + MST_RX_BYTES_XFRD),
>> + readl(idev->base + MST_RX_XFER),
>> + readl(idev->base + MST_TX_BYTES_XFRD),
>> + readl(idev->base + MST_TX_XFER));
>> + complete(&idev->msg_complete);
>> + }
>> +
>> +out:
>> + /* Clear interrupt */
>> + writel(INT_MST, idev->base + INTERRUPT_STATUS);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>
>
> Its looks good if we move the entire ISR above probe/remove
> functionalities...
>
Not sure what you mean here... The ISR _is_ above probe/remove.
/Anders
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 11:13 ` Anders Berg
@ 2014-09-29 11:14 ` Varka Bhadram
2014-09-29 12:51 ` Wolfram Sang
0 siblings, 1 reply; 9+ messages in thread
From: Varka Bhadram @ 2014-09-29 11:14 UTC (permalink / raw)
To: linux-arm-kernel
On 09/29/2014 04:43 PM, Anders Berg wrote:
> On Mon, Sep 29, 2014 at 12:07 PM, Varka Bhadram <varkabhadram@gmail.com> wrote:
>> On 09/29/2014 03:02 PM, Anders Berg wrote:
>>> Add I2C bus driver for the controller found in the LSI Axxia family SoCs.
>>> The
>>> driver implements 10-bit addressing and SMBus transfer modes via emulation
>>> (including SMBus block data read).
>>>
>>> Signed-off-by: Anders Berg <anders.berg@avagotech.com>
>>> ---
>>>
> (...)
>>> +
>>> + if (!idev->msg) {
>>> + dev_warn(idev->dev, "unexpected interrupt");
>>
>> Missed terminating new line '\n'
>>
> Right, I'll fix that (all occurrences)
>
>>> + goto out;
>>> + }
>>> +
>>> + /* RX FIFO needs service? */
>>> + if (i2c_m_rd(idev->msg) && (status & MST_STATUS_RFL))
>>> + axxia_i2c_empty_rx_fifo(idev);
>>> +
>>> + /* TX FIFO needs service? */
>>> + if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
>>> + if (axxia_i2c_fill_tx_fifo(idev) == 0)
>>> + i2c_int_disable(idev, MST_STATUS_TFL);
>>> + }
>>> +
>>> + if (status & MST_STATUS_SCC) {
>>> + /* Stop completed */
>>> + i2c_int_disable(idev, ~0);
>>> + complete(&idev->msg_complete);
>>> + } else if (status & MST_STATUS_SNS) {
>>> + /* Transfer done */
>>> + i2c_int_disable(idev, ~0);
>>> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd <
>>> idev->msg->len)
>>> + axxia_i2c_empty_rx_fifo(idev);
>>> + complete(&idev->msg_complete);
>>> + } else if (unlikely(status & MST_STATUS_ERR)) {
>>> + /* Transfer error */
>>> + i2c_int_disable(idev, ~0);
>>> + if (status & MST_STATUS_AL)
>>> + idev->msg_err = -EAGAIN;
>>> + else if (status & MST_STATUS_NAK)
>>> + idev->msg_err = -ENXIO;
>>> + else
>>> + idev->msg_err = -EIO;
>>> + dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u
>>> tx=%u/%u\n",
>>> + status,
>>> + idev->msg->addr,
>>> + readl(idev->base + MST_RX_BYTES_XFRD),
>>> + readl(idev->base + MST_RX_XFER),
>>> + readl(idev->base + MST_TX_BYTES_XFRD),
>>> + readl(idev->base + MST_TX_XFER));
>>> + complete(&idev->msg_complete);
>>> + }
>>> +
>>> +out:
>>> + /* Clear interrupt */
>>> + writel(INT_MST, idev->base + INTERRUPT_STATUS);
>>> +
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>
>> Its looks good if we move the entire ISR above probe/remove
>> functionalities...
>>
> Not sure what you mean here... The ISR _is_ above probe/remove.
I mean ISR should immediately above probe functionality. So that we can see
devm_request_irq(..,isr_name,..) ISR directly with isr name..
--
Regards,
Varka Bhadram.
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 11:14 ` Varka Bhadram
@ 2014-09-29 12:51 ` Wolfram Sang
0 siblings, 0 replies; 9+ messages in thread
From: Wolfram Sang @ 2014-09-29 12:51 UTC (permalink / raw)
To: linux-arm-kernel
> >>Its looks good if we move the entire ISR above probe/remove
> >>functionalities...
> >>
> >Not sure what you mean here... The ISR _is_ above probe/remove.
>
> I mean ISR should immediately above probe functionality. So that we can see
> devm_request_irq(..,isr_name,..) ISR directly with isr name..
Not so important to me, '*' in vim does that whereever the function is.
Still, thanks for the review!
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^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-09-29 9:32 [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx Anders Berg
2014-09-29 10:07 ` Varka Bhadram
@ 2014-10-03 10:36 ` Wolfram Sang
2014-10-03 11:04 ` Anders Berg
1 sibling, 1 reply; 9+ messages in thread
From: Wolfram Sang @ 2014-10-03 10:36 UTC (permalink / raw)
To: linux-arm-kernel
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 2ac87fa..8983474 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -77,6 +77,17 @@ config I2C_AMD8111
> This driver can also be built as a module. If so, the module
> will be called i2c-amd8111.
>
> +config I2C_AXXIA
> + tristate "Axxia I2C controller"
> + depends on ARCH_AXXIA || COMPILE_TEST
> + default ARCH_AXXIA
> + help
> + Say yes if you want to support the I2C bus on Axxia platforms.
> +
> + Please note that this controller is limited to transfers of maximum
> + 255 bytes in length. Any attempt to to a larger transfer will return
> + an error.
> +
> config I2C_I801
> tristate "Intel 82801 (ICH/PCH)"
> depends on PCI
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 49bf07e..5899edb 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o
> obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o
> obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o
> obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o
> +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
> obj-$(CONFIG_I2C_I801) += i2c-i801.o
> obj-$(CONFIG_I2C_ISCH) += i2c-isch.o
> obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o
Please put it to the embedded section.
...
> + idev->adapter.class = I2C_CLASS_HWMON;
Being a DT driver, you most probably don't need this.
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^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx
2014-10-03 10:36 ` Wolfram Sang
@ 2014-10-03 11:04 ` Anders Berg
0 siblings, 0 replies; 9+ messages in thread
From: Anders Berg @ 2014-10-03 11:04 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Oct 3, 2014 at 12:36 PM, Wolfram Sang <wsa@the-dreams.de> wrote:
>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>> index 2ac87fa..8983474 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -77,6 +77,17 @@ config I2C_AMD8111
>> This driver can also be built as a module. If so, the module
>> will be called i2c-amd8111.
>>
>> +config I2C_AXXIA
>> + tristate "Axxia I2C controller"
>> + depends on ARCH_AXXIA || COMPILE_TEST
>> + default ARCH_AXXIA
>> + help
>> + Say yes if you want to support the I2C bus on Axxia platforms.
>> +
>> + Please note that this controller is limited to transfers of maximum
>> + 255 bytes in length. Any attempt to to a larger transfer will return
>> + an error.
>> +
>> config I2C_I801
>> tristate "Intel 82801 (ICH/PCH)"
>> depends on PCI
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index 49bf07e..5899edb 100644
>> --- a/drivers/i2c/busses/Makefile
>> +++ b/drivers/i2c/busses/Makefile
>> @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3) += i2c-ali15x3.o
>> obj-$(CONFIG_I2C_AMD756) += i2c-amd756.o
>> obj-$(CONFIG_I2C_AMD756_S4882) += i2c-amd756-s4882.o
>> obj-$(CONFIG_I2C_AMD8111) += i2c-amd8111.o
>> +obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o
>> obj-$(CONFIG_I2C_I801) += i2c-i801.o
>> obj-$(CONFIG_I2C_ISCH) += i2c-isch.o
>> obj-$(CONFIG_I2C_ISMT) += i2c-ismt.o
>
> Please put it to the embedded section.
>
OK.
> ...
>
>> + idev->adapter.class = I2C_CLASS_HWMON;
>
> Being a DT driver, you most probably don't need this.
>
Right, thanks. I'll fix up these and submit a v3.
/Anders
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-10-03 11:04 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-09-29 9:32 [PATCH v2] i2c: axxia: Add I2C driver for AXM55xx Anders Berg
2014-09-29 10:07 ` Varka Bhadram
2014-09-29 10:13 ` Wolfram Sang
2014-09-29 10:13 ` Varka Bhadram
2014-09-29 11:13 ` Anders Berg
2014-09-29 11:14 ` Varka Bhadram
2014-09-29 12:51 ` Wolfram Sang
2014-10-03 10:36 ` Wolfram Sang
2014-10-03 11:04 ` Anders Berg
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