diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-cht-wc.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-cht-wc.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-cht-wc.c b/drivers/i2c/busses/i2c-cht-wc.c new file mode 100644 index 000000000000..190bbbc7bfee --- /dev/null +++ b/drivers/i2c/busses/i2c-cht-wc.c @@ -0,0 +1,363 @@ +/* + * Intel CHT Whiskey Cove PMIC I2C Master driver + * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com> + * + * Based on various non upstream patches to support the CHT Whiskey Cove PMIC: + * Copyright (C) 2011 - 2014 Intel Corporation. All rights reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/irqdomain.h> +#include <linux/mfd/intel_soc_pmic.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#define CHT_WC_I2C_CTRL 0x5e24 +#define CHT_WC_I2C_CTRL_WR BIT(0) +#define CHT_WC_I2C_CTRL_RD BIT(1) +#define CHT_WC_I2C_CLIENT_ADDR 0x5e25 +#define CHT_WC_I2C_REG_OFFSET 0x5e26 +#define CHT_WC_I2C_WRDATA 0x5e27 +#define CHT_WC_I2C_RDDATA 0x5e28 + +#define CHT_WC_EXTCHGRIRQ 0x6e0a +#define CHT_WC_EXTCHGRIRQ_CLIENT_IRQ BIT(0) +#define CHT_WC_EXTCHGRIRQ_WRITE_IRQ BIT(1) +#define CHT_WC_EXTCHGRIRQ_READ_IRQ BIT(2) +#define CHT_WC_EXTCHGRIRQ_NACK_IRQ BIT(3) +#define CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK ((u8)GENMASK(3, 1)) +#define CHT_WC_EXTCHGRIRQ_MSK 0x6e17 + +struct cht_wc_i2c_adap { + struct i2c_adapter adapter; + wait_queue_head_t wait; + struct irq_chip irqchip; + struct mutex adap_lock; + struct mutex irqchip_lock; + struct regmap *regmap; + struct irq_domain *irq_domain; + struct i2c_client *client; + int client_irq; + u8 irq_mask; + u8 old_irq_mask; + int read_data; + bool io_error; + bool done; +}; + +static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data) +{ + struct cht_wc_i2c_adap *adap = data; + int ret, reg; + + mutex_lock(&adap->adap_lock); + + /* Read IRQs */ + ret = regmap_read(adap->regmap, CHT_WC_EXTCHGRIRQ, ®); + if (ret) { + dev_err(&adap->adapter.dev, "Error reading extchgrirq reg\n"); + mutex_unlock(&adap->adap_lock); + return IRQ_NONE; + } + + reg &= ~adap->irq_mask; + + /* Reads must be acked after reading the received data. */ + ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &adap->read_data); + if (ret) + adap->io_error = true; + + /* + * Immediately ack IRQs, so that if new IRQs arrives while we're + * handling the previous ones our irq will re-trigger when we're done. + */ + ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, reg); + if (ret) + dev_err(&adap->adapter.dev, "Error writing extchgrirq reg\n"); + + if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) { + adap->io_error |= !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ); + adap->done = true; + } + + mutex_unlock(&adap->adap_lock); + + if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) + wake_up(&adap->wait); + + /* + * Do NOT use handle_nested_irq here, the client irq handler will + * likely want to do i2c transfers and the i2c controller uses this + * interrupt handler as well, so running the client irq handler from + * this thread will cause things to lock up. + */ + if (reg & CHT_WC_EXTCHGRIRQ_CLIENT_IRQ) { + /* + * generic_handle_irq expects local IRQs to be disabled + * as normally it is called from interrupt context. + */ + local_irq_disable(); + generic_handle_irq(adap->client_irq); + local_irq_enable(); + } + + return IRQ_HANDLED; +} + +static u32 cht_wc_i2c_adap_master_func(struct i2c_adapter *adap) +{ + /* This i2c adapter only supports SMBUS byte transfers */ + return I2C_FUNC_SMBUS_BYTE_DATA; +} + +static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16 addr, + unsigned short flags, char read_write, + u8 command, int size, + union i2c_smbus_data *data) +{ + struct cht_wc_i2c_adap *adap = i2c_get_adapdata(_adap); + int ret; + + mutex_lock(&adap->adap_lock); + adap->io_error = false; + adap->done = false; + mutex_unlock(&adap->adap_lock); + + ret = regmap_write(adap->regmap, CHT_WC_I2C_CLIENT_ADDR, addr); + if (ret) + return ret; + + if (read_write == I2C_SMBUS_WRITE) { + ret = regmap_write(adap->regmap, CHT_WC_I2C_WRDATA, data->byte); + if (ret) + return ret; + } + + ret = regmap_write(adap->regmap, CHT_WC_I2C_REG_OFFSET, command); + if (ret) + return ret; + + ret = regmap_write(adap->regmap, CHT_WC_I2C_CTRL, + (read_write == I2C_SMBUS_WRITE) ? + CHT_WC_I2C_CTRL_WR : CHT_WC_I2C_CTRL_RD); + if (ret) + return ret; + + ret = wait_event_timeout(adap->wait, adap->done, msecs_to_jiffies(30)); + if (ret == 0) { + /* + * The CHT GPIO controller serializes all IRQs, sometimes + * causing significant delays, check status manually. + */ + cht_wc_i2c_adap_thread_handler(0, adap); + if (!adap->done) + return -ETIMEDOUT; + } + + ret = 0; + mutex_lock(&adap->adap_lock); + if (adap->io_error) + ret = -EIO; + else if (read_write == I2C_SMBUS_READ) + data->byte = adap->read_data; + mutex_unlock(&adap->adap_lock); + + return ret; +} + +static const struct i2c_algorithm cht_wc_i2c_adap_algo = { + .functionality = cht_wc_i2c_adap_master_func, + .smbus_xfer = cht_wc_i2c_adap_smbus_xfer, +}; + +/**** irqchip for the client connected to the extchgr i2c adapter ****/ +static void cht_wc_i2c_irq_lock(struct irq_data *data) +{ + struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data); + + mutex_lock(&adap->irqchip_lock); +} + +static void cht_wc_i2c_irq_sync_unlock(struct irq_data *data) +{ + struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data); + int ret; + + if (adap->irq_mask != adap->old_irq_mask) { + ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK, + adap->irq_mask); + if (ret == 0) + adap->old_irq_mask = adap->irq_mask; + else + dev_err(&adap->adapter.dev, "Error writing EXTCHGRIRQ_MSK\n"); + } + + mutex_unlock(&adap->irqchip_lock); +} + +static void cht_wc_i2c_irq_enable(struct irq_data *data) +{ + struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data); + + adap->irq_mask &= ~CHT_WC_EXTCHGRIRQ_CLIENT_IRQ; +} + +static void cht_wc_i2c_irq_disable(struct irq_data *data) +{ + struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data); + + adap->irq_mask |= CHT_WC_EXTCHGRIRQ_CLIENT_IRQ; +} + +static const struct irq_chip cht_wc_i2c_irq_chip = { + .irq_bus_lock = cht_wc_i2c_irq_lock, + .irq_bus_sync_unlock = cht_wc_i2c_irq_sync_unlock, + .irq_disable = cht_wc_i2c_irq_disable, + .irq_enable = cht_wc_i2c_irq_enable, + .name = "cht_wc_ext_chrg_irq_chip", +}; + +static const struct property_entry bq24190_props[] = { + PROPERTY_ENTRY_STRING("extcon-name", "cht_wcove_pwrsrc"), + PROPERTY_ENTRY_BOOL("omit-battery-class"), + PROPERTY_ENTRY_BOOL("disable-reset"), + { } +}; + +static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev) +{ + struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent); + struct cht_wc_i2c_adap *adap; + struct i2c_board_info board_info = { + .type = "bq24190", + .addr = 0x6b, + .properties = bq24190_props, + }; + int ret, reg, irq; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "Error missing irq resource\n"); + return -EINVAL; + } + + adap = devm_kzalloc(&pdev->dev, sizeof(*adap), GFP_KERNEL); + if (!adap) + return -ENOMEM; + + init_waitqueue_head(&adap->wait); + mutex_init(&adap->adap_lock); + mutex_init(&adap->irqchip_lock); + adap->irqchip = cht_wc_i2c_irq_chip; + adap->regmap = pmic->regmap; + adap->adapter.owner = THIS_MODULE; + adap->adapter.class = I2C_CLASS_HWMON; + adap->adapter.algo = &cht_wc_i2c_adap_algo; + strlcpy(adap->adapter.name, "PMIC I2C Adapter", + sizeof(adap->adapter.name)); + adap->adapter.dev.parent = &pdev->dev; + + /* Clear and activate i2c-adapter interrupts, disable client IRQ */ + adap->old_irq_mask = adap->irq_mask = ~CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK; + + ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, ®); + if (ret) + return ret; + + ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, ~adap->irq_mask); + if (ret) + return ret; + + ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK, adap->irq_mask); + if (ret) + return ret; + + /* Alloc and register client IRQ */ + adap->irq_domain = irq_domain_add_linear(pdev->dev.of_node, 1, + &irq_domain_simple_ops, NULL); + if (!adap->irq_domain) + return -ENOMEM; + + adap->client_irq = irq_create_mapping(adap->irq_domain, 0); + if (!adap->client_irq) { + ret = -ENOMEM; + goto remove_irq_domain; + } + + irq_set_chip_data(adap->client_irq, adap); + irq_set_chip_and_handler(adap->client_irq, &adap->irqchip, + handle_simple_irq); + + ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, + cht_wc_i2c_adap_thread_handler, + IRQF_ONESHOT, "PMIC I2C Adapter", adap); + if (ret) + goto remove_irq_domain; + + i2c_set_adapdata(&adap->adapter, adap); + ret = i2c_add_adapter(&adap->adapter); + if (ret) + goto remove_irq_domain; + + board_info.irq = adap->client_irq; + adap->client = i2c_new_device(&adap->adapter, &board_info); + if (!adap->client) { + ret = -ENOMEM; + goto del_adapter; + } + + platform_set_drvdata(pdev, adap); + return 0; + +del_adapter: + i2c_del_adapter(&adap->adapter); +remove_irq_domain: + irq_domain_remove(adap->irq_domain); + return ret; +} + +static int cht_wc_i2c_adap_i2c_remove(struct platform_device *pdev) +{ + struct cht_wc_i2c_adap *adap = platform_get_drvdata(pdev); + + i2c_unregister_device(adap->client); + i2c_del_adapter(&adap->adapter); + irq_domain_remove(adap->irq_domain); + + return 0; +} + +static struct platform_device_id cht_wc_i2c_adap_id_table[] = { + { .name = "cht_wcove_ext_chgr" }, + {}, +}; +MODULE_DEVICE_TABLE(platform, cht_wc_i2c_adap_id_table); + +static struct platform_driver cht_wc_i2c_adap_driver = { + .probe = cht_wc_i2c_adap_i2c_probe, + .remove = cht_wc_i2c_adap_i2c_remove, + .driver = { + .name = "cht_wcove_ext_chgr", + }, + .id_table = cht_wc_i2c_adap_id_table, +}; +module_platform_driver(cht_wc_i2c_adap_driver); + +MODULE_DESCRIPTION("Intel CHT Whiskey Cove PMIC I2C Master driver"); +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>"); +MODULE_LICENSE("GPL"); |