diff options
author | Conor Dooley <conor.dooley@microchip.com> | 2022-07-06 15:13:13 +0100 |
---|---|---|
committer | Wolfram Sang <wsa@kernel.org> | 2022-07-07 22:54:29 +0200 |
commit | 64a6f1c4987e027339818b9d142257e7ede6dfe0 (patch) | |
tree | 840ee39de29445ed95346af08af8ed53b5cc14f2 | |
parent | 24fff66f1f26d618d3b16c36603c10175e3d660f (diff) |
i2c: add support for microchip fpga i2c controllers
Add Microchip CoreI2C i2c controller support. This driver supports the
"hard" i2c controller on the Microchip PolarFire SoC & the basic feature
set for "soft" i2c controller implemtations in the FPGA fabric.
Co-developed-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
-rw-r--r-- | drivers/i2c/busses/Kconfig | 11 | ||||
-rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
-rw-r--r-- | drivers/i2c/busses/i2c-microchip-corei2c.c | 480 |
3 files changed, 492 insertions, 0 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 3f6d03073079..f77f51b273a4 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -782,6 +782,17 @@ config I2C_MESON If you say yes to this option, support will be included for the I2C interface on the Amlogic Meson family of SoCs. +config I2C_MICROCHIP_CORE + tristate "Microchip FPGA I2C controller" + depends on SOC_MICROCHIP_POLARFIRE || COMPILE_TEST + depends on OF + help + If you say yes to this option, support will be included for the + I2C interface on Microchip FPGAs. + + This driver can also be built as a module. If so, the module will be + called i2c-microchip-core. + config I2C_MPC tristate "MPC107/824x/85xx/512x/52xx/83xx/86xx" depends on PPC diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index b0a10e5d9ee9..29d729b6a5b7 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -78,6 +78,7 @@ obj-$(CONFIG_I2C_JZ4780) += i2c-jz4780.o obj-$(CONFIG_I2C_KEMPLD) += i2c-kempld.o obj-$(CONFIG_I2C_LPC2K) += i2c-lpc2k.o obj-$(CONFIG_I2C_MESON) += i2c-meson.o +obj-$(CONFIG_I2C_MICROCHIP_CORE) += i2c-microchip-corei2c.o obj-$(CONFIG_I2C_MPC) += i2c-mpc.o obj-$(CONFIG_I2C_MT65XX) += i2c-mt65xx.o obj-$(CONFIG_I2C_MT7621) += i2c-mt7621.o diff --git a/drivers/i2c/busses/i2c-microchip-corei2c.c b/drivers/i2c/busses/i2c-microchip-corei2c.c new file mode 100644 index 000000000000..6df0f1c33278 --- /dev/null +++ b/drivers/i2c/busses/i2c-microchip-corei2c.c @@ -0,0 +1,480 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Microchip CoreI2C I2C controller driver + * + * Copyright (c) 2018-2022 Microchip Corporation. All rights reserved. + * + * Author: Daire McNamara <daire.mcnamara@microchip.com> + * Author: Conor Dooley <conor.dooley@microchip.com> + */ +#include <linux/clk.h> +#include <linux/clkdev.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +#define CORE_I2C_CTRL (0x00) +#define CTRL_CR0 BIT(0) +#define CTRL_CR1 BIT(1) +#define CTRL_AA BIT(2) +#define CTRL_SI BIT(3) +#define CTRL_STO BIT(4) +#define CTRL_STA BIT(5) +#define CTRL_ENS1 BIT(6) +#define CTRL_CR2 BIT(7) + +#define STATUS_BUS_ERROR (0x00) +#define STATUS_M_START_SENT (0x08) +#define STATUS_M_REPEATED_START_SENT (0x10) +#define STATUS_M_SLAW_ACK (0x18) +#define STATUS_M_SLAW_NACK (0x20) +#define STATUS_M_TX_DATA_ACK (0x28) +#define STATUS_M_TX_DATA_NACK (0x30) +#define STATUS_M_ARB_LOST (0x38) +#define STATUS_M_SLAR_ACK (0x40) +#define STATUS_M_SLAR_NACK (0x48) +#define STATUS_M_RX_DATA_ACKED (0x50) +#define STATUS_M_RX_DATA_NACKED (0x58) +#define STATUS_S_SLAW_ACKED (0x60) +#define STATUS_S_ARB_LOST_SLAW_ACKED (0x68) +#define STATUS_S_GENERAL_CALL_ACKED (0x70) +#define STATUS_S_ARB_LOST_GENERAL_CALL_ACKED (0x78) +#define STATUS_S_RX_DATA_ACKED (0x80) +#define STATUS_S_RX_DATA_NACKED (0x88) +#define STATUS_S_GENERAL_CALL_RX_DATA_ACKED (0x90) +#define STATUS_S_GENERAL_CALL_RX_DATA_NACKED (0x98) +#define STATUS_S_RX_STOP (0xA0) +#define STATUS_S_SLAR_ACKED (0xA8) +#define STATUS_S_ARB_LOST_SLAR_ACKED (0xB0) +#define STATUS_S_TX_DATA_ACK (0xB8) +#define STATUS_S_TX_DATA_NACK (0xC0) +#define STATUS_LAST_DATA_ACK (0xC8) +#define STATUS_M_SMB_MASTER_RESET (0xD0) +#define STATUS_S_SCL_LOW_TIMEOUT (0xD8) /* 25 ms */ +#define STATUS_NO_STATE_INFO (0xF8) + +#define CORE_I2C_STATUS (0x04) +#define CORE_I2C_DATA (0x08) +#define WRITE_BIT (0x0) +#define READ_BIT (0x1) +#define SLAVE_ADDR_SHIFT (1) +#define CORE_I2C_SLAVE0_ADDR (0x0c) +#define GENERAL_CALL_BIT (0x0) +#define CORE_I2C_SMBUS (0x10) +#define SMBALERT_INT_ENB (0x0) +#define SMBSUS_INT_ENB (0x1) +#define SMBUS_ENB (0x2) +#define SMBALERT_NI_STATUS (0x3) +#define SMBALERT_NO_CTRL (0x4) +#define SMBSUS_NI_STATUS (0x5) +#define SMBSUS_NO_CTRL (0x6) +#define SMBUS_RESET (0x7) +#define CORE_I2C_FREQ (0x14) +#define CORE_I2C_GLITCHREG (0x18) +#define CORE_I2C_SLAVE1_ADDR (0x1c) + +#define PCLK_DIV_960 (CTRL_CR2) +#define PCLK_DIV_256 (0) +#define PCLK_DIV_224 (CTRL_CR0) +#define PCLK_DIV_192 (CTRL_CR1) +#define PCLK_DIV_160 (CTRL_CR0 | CTRL_CR1) +#define PCLK_DIV_120 (CTRL_CR0 | CTRL_CR2) +#define PCLK_DIV_60 (CTRL_CR1 | CTRL_CR2) +#define BCLK_DIV_8 (CTRL_CR0 | CTRL_CR1 | CTRL_CR2) +#define CLK_MASK (CTRL_CR0 | CTRL_CR1 | CTRL_CR2) + +/** + * struct mchp_corei2c_dev - Microchip CoreI2C device private data + * + * @base: pointer to register struct + * @dev: device reference + * @i2c_clk: clock reference for i2c input clock + * @buf: pointer to msg buffer for easier use + * @msg_complete: xfer completion object + * @adapter: core i2c abstraction + * @msg_err: error code for completed message + * @bus_clk_rate: current i2c bus clock rate + * @isr_status: cached copy of local ISR status + * @msg_len: number of bytes transferred in msg + * @addr: address of the current slave + */ +struct mchp_corei2c_dev { + void __iomem *base; + struct device *dev; + struct clk *i2c_clk; + u8 *buf; + struct completion msg_complete; + struct i2c_adapter adapter; + int msg_err; + u32 bus_clk_rate; + u32 isr_status; + u16 msg_len; + u8 addr; +}; + +static void mchp_corei2c_core_disable(struct mchp_corei2c_dev *idev) +{ + u8 ctrl = readb(idev->base + CORE_I2C_CTRL); + + ctrl &= ~CTRL_ENS1; + writeb(ctrl, idev->base + CORE_I2C_CTRL); +} + +static void mchp_corei2c_core_enable(struct mchp_corei2c_dev *idev) +{ + u8 ctrl = readb(idev->base + CORE_I2C_CTRL); + + ctrl |= CTRL_ENS1; + writeb(ctrl, idev->base + CORE_I2C_CTRL); +} + +static void mchp_corei2c_reset(struct mchp_corei2c_dev *idev) +{ + mchp_corei2c_core_disable(idev); + mchp_corei2c_core_enable(idev); +} + +static inline void mchp_corei2c_stop(struct mchp_corei2c_dev *idev) +{ + u8 ctrl = readb(idev->base + CORE_I2C_CTRL); + + ctrl |= CTRL_STO; + writeb(ctrl, idev->base + CORE_I2C_CTRL); +} + +static inline int mchp_corei2c_set_divisor(u32 rate, + struct mchp_corei2c_dev *idev) +{ + u8 clkval, ctrl; + + if (rate >= 960) + clkval = PCLK_DIV_960; + else if (rate >= 256) + clkval = PCLK_DIV_256; + else if (rate >= 224) + clkval = PCLK_DIV_224; + else if (rate >= 192) + clkval = PCLK_DIV_192; + else if (rate >= 160) + clkval = PCLK_DIV_160; + else if (rate >= 120) + clkval = PCLK_DIV_120; + else if (rate >= 60) + clkval = PCLK_DIV_60; + else if (rate >= 8) + clkval = BCLK_DIV_8; + else + return -EINVAL; + + ctrl = readb(idev->base + CORE_I2C_CTRL); + ctrl &= ~CLK_MASK; + ctrl |= clkval; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + + ctrl = readb(idev->base + CORE_I2C_CTRL); + if ((ctrl & CLK_MASK) != clkval) + return -EIO; + + return 0; +} + +static int mchp_corei2c_init(struct mchp_corei2c_dev *idev) +{ + u32 clk_rate = clk_get_rate(idev->i2c_clk); + u32 divisor = clk_rate / idev->bus_clk_rate; + int ret; + + ret = mchp_corei2c_set_divisor(divisor, idev); + if (ret) + return ret; + + mchp_corei2c_reset(idev); + + return 0; +} + +static void mchp_corei2c_empty_rx(struct mchp_corei2c_dev *idev) +{ + u8 ctrl; + + if (idev->msg_len > 0) { + *idev->buf++ = readb(idev->base + CORE_I2C_DATA); + idev->msg_len--; + } + + if (idev->msg_len == 0) { + ctrl = readb(idev->base + CORE_I2C_CTRL); + ctrl &= ~CTRL_AA; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + } +} + +static int mchp_corei2c_fill_tx(struct mchp_corei2c_dev *idev) +{ + if (idev->msg_len > 0) + writeb(*idev->buf++, idev->base + CORE_I2C_DATA); + idev->msg_len--; + + return 0; +} + +static irqreturn_t mchp_corei2c_handle_isr(struct mchp_corei2c_dev *idev) +{ + u32 status = idev->isr_status; + u8 ctrl; + bool last_byte = false, finished = false; + + if (!idev->buf) + return IRQ_NONE; + + switch (status) { + case STATUS_M_START_SENT: + case STATUS_M_REPEATED_START_SENT: + ctrl = readb(idev->base + CORE_I2C_CTRL); + ctrl &= ~CTRL_STA; + writeb(idev->addr, idev->base + CORE_I2C_DATA); + writeb(ctrl, idev->base + CORE_I2C_CTRL); + if (idev->msg_len == 0) + finished = true; + break; + case STATUS_M_ARB_LOST: + idev->msg_err = -EAGAIN; + finished = true; + break; + case STATUS_M_SLAW_ACK: + case STATUS_M_TX_DATA_ACK: + if (idev->msg_len > 0) + mchp_corei2c_fill_tx(idev); + else + last_byte = true; + break; + case STATUS_M_TX_DATA_NACK: + case STATUS_M_SLAR_NACK: + case STATUS_M_SLAW_NACK: + idev->msg_err = -ENXIO; + last_byte = true; + break; + case STATUS_M_SLAR_ACK: + ctrl = readb(idev->base + CORE_I2C_CTRL); + if (idev->msg_len == 1u) { + ctrl &= ~CTRL_AA; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + } else { + ctrl |= CTRL_AA; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + } + if (idev->msg_len < 1u) + last_byte = true; + break; + case STATUS_M_RX_DATA_ACKED: + mchp_corei2c_empty_rx(idev); + break; + case STATUS_M_RX_DATA_NACKED: + mchp_corei2c_empty_rx(idev); + if (idev->msg_len == 0) + last_byte = true; + break; + default: + break; + } + + /* On the last byte to be transmitted, send STOP */ + if (last_byte) + mchp_corei2c_stop(idev); + + if (last_byte || finished) + complete(&idev->msg_complete); + + return IRQ_HANDLED; +} + +static irqreturn_t mchp_corei2c_isr(int irq, void *_dev) +{ + struct mchp_corei2c_dev *idev = _dev; + irqreturn_t ret = IRQ_NONE; + u8 ctrl; + + ctrl = readb(idev->base + CORE_I2C_CTRL); + if (ctrl & CTRL_SI) { + idev->isr_status = readb(idev->base + CORE_I2C_STATUS); + ret = mchp_corei2c_handle_isr(idev); + } + + ctrl = readb(idev->base + CORE_I2C_CTRL); + ctrl &= ~CTRL_SI; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + + return ret; +} + +static int mchp_corei2c_xfer_msg(struct mchp_corei2c_dev *idev, + struct i2c_msg *msg) +{ + u8 ctrl; + unsigned long time_left; + + idev->addr = i2c_8bit_addr_from_msg(msg); + idev->msg_len = msg->len; + idev->buf = msg->buf; + idev->msg_err = 0; + + reinit_completion(&idev->msg_complete); + + mchp_corei2c_core_enable(idev); + + ctrl = readb(idev->base + CORE_I2C_CTRL); + ctrl |= CTRL_STA; + writeb(ctrl, idev->base + CORE_I2C_CTRL); + + time_left = wait_for_completion_timeout(&idev->msg_complete, + idev->adapter.timeout); + if (!time_left) + return -ETIMEDOUT; + + return idev->msg_err; +} + +static int mchp_corei2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct mchp_corei2c_dev *idev = i2c_get_adapdata(adap); + int i, ret; + + for (i = 0; i < num; i++) { + ret = mchp_corei2c_xfer_msg(idev, msgs++); + if (ret) + return ret; + } + + return num; +} + +static u32 mchp_corei2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm mchp_corei2c_algo = { + .master_xfer = mchp_corei2c_xfer, + .functionality = mchp_corei2c_func, +}; + +static int mchp_corei2c_probe(struct platform_device *pdev) +{ + struct mchp_corei2c_dev *idev; + struct resource *res; + int irq, ret; + + idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL); + if (!idev) + return -ENOMEM; + + idev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); + if (IS_ERR(idev->base)) + return PTR_ERR(idev->base); + + irq = platform_get_irq(pdev, 0); + if (irq <= 0) + return dev_err_probe(&pdev->dev, -ENXIO, + "invalid IRQ %d for I2C controller\n", irq); + + idev->i2c_clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(idev->i2c_clk)) + return dev_err_probe(&pdev->dev, PTR_ERR(idev->i2c_clk), + "missing clock\n"); + + idev->dev = &pdev->dev; + init_completion(&idev->msg_complete); + + ret = device_property_read_u32(idev->dev, "clock-frequency", + &idev->bus_clk_rate); + if (ret || !idev->bus_clk_rate) { + dev_info(&pdev->dev, "default to 100kHz\n"); + idev->bus_clk_rate = 100000; + } + + if (idev->bus_clk_rate > 400000) + return dev_err_probe(&pdev->dev, -EINVAL, + "clock-frequency too high: %d\n", + idev->bus_clk_rate); + + /* + * This driver supports both the hard peripherals & soft FPGA cores. + * The hard peripherals do not have shared IRQs, but we don't have + * control over what way the interrupts are wired for the soft cores. + */ + ret = devm_request_irq(&pdev->dev, irq, mchp_corei2c_isr, IRQF_SHARED, + pdev->name, idev); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "failed to claim irq %d\n", irq); + + ret = clk_prepare_enable(idev->i2c_clk); + if (ret) + return dev_err_probe(&pdev->dev, ret, + "failed to enable clock\n"); + + ret = mchp_corei2c_init(idev); + if (ret) { + clk_disable_unprepare(idev->i2c_clk); + return dev_err_probe(&pdev->dev, ret, "failed to program clock divider\n"); + } + + i2c_set_adapdata(&idev->adapter, idev); + snprintf(idev->adapter.name, sizeof(idev->adapter.name), + "Microchip I2C hw bus at %08lx", (unsigned long)res->start); + idev->adapter.owner = THIS_MODULE; + idev->adapter.algo = &mchp_corei2c_algo; + idev->adapter.dev.parent = &pdev->dev; + idev->adapter.dev.of_node = pdev->dev.of_node; + idev->adapter.timeout = HZ; + + platform_set_drvdata(pdev, idev); + + ret = i2c_add_adapter(&idev->adapter); + if (ret) { + clk_disable_unprepare(idev->i2c_clk); + return ret; + } + + dev_info(&pdev->dev, "registered CoreI2C bus driver\n"); + + return 0; +} + +static int mchp_corei2c_remove(struct platform_device *pdev) +{ + struct mchp_corei2c_dev *idev = platform_get_drvdata(pdev); + + clk_disable_unprepare(idev->i2c_clk); + i2c_del_adapter(&idev->adapter); + + return 0; +} + +static const struct of_device_id mchp_corei2c_of_match[] = { + { .compatible = "microchip,mpfs-i2c" }, + { .compatible = "microchip,corei2c-rtl-v7" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mchp_corei2c_of_match); + +static struct platform_driver mchp_corei2c_driver = { + .probe = mchp_corei2c_probe, + .remove = mchp_corei2c_remove, + .driver = { + .name = "microchip-corei2c", + .of_match_table = mchp_corei2c_of_match, + }, +}; + +module_platform_driver(mchp_corei2c_driver); + +MODULE_DESCRIPTION("Microchip CoreI2C bus driver"); +MODULE_AUTHOR("Daire McNamara <daire.mcnamara@microchip.com>"); +MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>"); +MODULE_LICENSE("GPL"); |