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Mon, 09 Feb 2026 02:44:28 -0800 (PST) From: Svyatoslav Ryhel To: Lee Jones , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Dmitry Torokhov , Pavel Machek , Arnd Bergmann , Greg Kroah-Hartman , Sebastian Reichel , Svyatoslav Ryhel , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Ion Agorria Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, linux-leds@vger.kernel.org, linux-pm@vger.kernel.org Subject: [PATCH v2 2/9] misc: Support Asus Transformer's EC access device Date: Mon, 9 Feb 2026 12:44:00 +0200 Message-ID: <20260209104407.116426-3-clamor95@gmail.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260209104407.116426-1-clamor95@gmail.com> References: <20260209104407.116426-1-clamor95@gmail.com> Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Michał Mirosław Add support for accessing Embedded Controller of Asus Transformer devices. This will be used by the EC MFD drivers. Co-developed-by: Svyatoslav Ryhel Signed-off-by: Svyatoslav Ryhel Signed-off-by: Michał Mirosław --- drivers/misc/Kconfig | 9 + drivers/misc/Makefile | 1 + drivers/misc/asus-dockram.c | 370 ++++++++++++++++++++++++++++++++++++ include/linux/mfd/asus-ec.h | 24 +++ 4 files changed, 404 insertions(+) create mode 100644 drivers/misc/asus-dockram.c create mode 100644 include/linux/mfd/asus-ec.h diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index dd1ab7e445ac..e7faa7ab4199 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -50,6 +50,15 @@ config AD525X_DPOT_SPI To compile this driver as a module, choose M here: the module will be called ad525x_dpot-spi. +config ASUS_DOCKRAM + tristate "Asus Transformer's EC DockRAM" + depends on I2C + help + Select this if you are building for Asus Transformer's. + + To compile this driver as a module, choose M here: the + module will be called asus-dockram. + config DUMMY_IRQ tristate "Dummy IRQ handler" help diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index bfad6982591c..d2287e912d59 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_IBMVMC) += ibmvmc.o obj-$(CONFIG_AD525X_DPOT) += ad525x_dpot.o obj-$(CONFIG_AD525X_DPOT_I2C) += ad525x_dpot-i2c.o obj-$(CONFIG_AD525X_DPOT_SPI) += ad525x_dpot-spi.o +obj-$(CONFIG_ASUS_DOCKRAM) += asus-dockram.o obj-$(CONFIG_ATMEL_SSC) += atmel-ssc.o obj-$(CONFIG_DUMMY_IRQ) += dummy-irq.o obj-$(CONFIG_ICS932S401) += ics932s401.o diff --git a/drivers/misc/asus-dockram.c b/drivers/misc/asus-dockram.c new file mode 100644 index 000000000000..ecda7b0c6d63 --- /dev/null +++ b/drivers/misc/asus-dockram.c @@ -0,0 +1,370 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * ASUS EC: DockRAM + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct dockram_ec_data { + struct mutex ctl_lock; /* prevent simultaneous access */ + char ctl_data[DOCKRAM_ENTRY_BUFSIZE]; +}; + +/** + * asus_dockram_read - Read a register from the DockRAM device. + * @client: Handle to the DockRAM device. + * @reg: Register to read. + * @buf: Byte array into which data will be read; must be large enough to + * hold the data returned by the DockRAM. + * + * This executes the DockRAM read based on the SMBus "block read" protocol + * or its emulation. It extracts DOCKRAM_ENTRY_SIZE bytes from the set + * register address. + * + * Returns a negative errno code else zero on success. + */ +int asus_dockram_read(struct i2c_client *client, int reg, char *buf) +{ + struct device *dev = &client->dev; + int ret; + + memset(buf, 0, DOCKRAM_ENTRY_BUFSIZE); + ret = i2c_smbus_read_i2c_block_data(client, reg, DOCKRAM_ENTRY_BUFSIZE, buf); + if (ret < 0) + return ret; + + if (buf[0] > DOCKRAM_ENTRY_SIZE) { + dev_err(dev, "bad data len; buffer: %*ph; ret: %d\n", + DOCKRAM_ENTRY_BUFSIZE, buf, ret); + return -EPROTO; + } + + dev_dbg(dev, "got data; buffer: %*ph; ret: %d\n", + DOCKRAM_ENTRY_BUFSIZE, buf, ret); + + return 0; +} +EXPORT_SYMBOL_GPL(asus_dockram_read); + +/** + * asus_dockram_write - Write a byte array to a register of the DockRAM device. + * @client: Handle to the DockRAM device. + * @reg: Register to write to. + * @buf: Byte array to be written (up to DOCKRAM_ENTRY_SIZE bytes). + * + * This executes the DockRAM write based on the SMBus "block write" protocol + * or its emulation. It writes DOCKRAM_ENTRY_SIZE bytes to the specified + * register address. + * + * Returns a negative errno code else zero on success. + */ +int asus_dockram_write(struct i2c_client *client, int reg, const char *buf) +{ + if (buf[0] > DOCKRAM_ENTRY_SIZE) + return -EINVAL; + + dev_dbg(&client->dev, "sending data; buffer: %*ph\n", buf[0] + 1, buf); + + return i2c_smbus_write_i2c_block_data(client, reg, buf[0] + 1, buf); +} +EXPORT_SYMBOL_GPL(asus_dockram_write); + +/** + * asus_dockram_access_ctl - Read from or write to the DockRAM control register. + * @client: Handle to the DockRAM device. + * @out: Pointer to a variable where the register value will be stored. + * @mask: Bitmask of bits to be cleared. + * @xor: Bitmask of bits to be set (via XOR). + * + * This performs a control register read if @out is provided and both @mask + * and @xor are zero. Otherwise, it performs a control register update if + * @mask and @xor are provided. + * + * Returns a negative errno code else zero on success. + */ +int asus_dockram_access_ctl(struct i2c_client *client, u64 *out, u64 mask, + u64 xor) +{ + struct dockram_ec_data *priv = i2c_get_clientdata(client); + char *buf = priv->ctl_data; + u64 val; + int ret = 0; + + guard(mutex)(&priv->ctl_lock); + + ret = asus_dockram_read(client, ASUSEC_DOCKRAM_CONTROL, buf); + if (ret < 0) + goto exit; + + if (buf[0] != ASUSEC_CTL_SIZE) { + ret = -EPROTO; + goto exit; + } + + val = get_unaligned_le64(buf + 1); + + if (out) + *out = val; + + if (mask || xor) { + put_unaligned_le64((val & ~mask) ^ xor, buf + 1); + ret = asus_dockram_write(client, ASUSEC_DOCKRAM_CONTROL, buf); + } + +exit: + if (ret < 0) + dev_err(&client->dev, "Failed to access control flags: %d\n", + ret); + + return ret; +} +EXPORT_SYMBOL_GPL(asus_dockram_access_ctl); + +static ssize_t dockram_read(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct i2c_client *client = filp->private_data; + unsigned int reg, rsize; + ssize_t n_read = 0, val; + loff_t off = *ppos; + char *data; + int ret; + + reg = off / DOCKRAM_ENTRY_SIZE; + off %= DOCKRAM_ENTRY_SIZE; + rsize = DOCKRAM_ENTRIES * DOCKRAM_ENTRY_SIZE; + + if (!count) + return 0; + + data = kmalloc(DOCKRAM_ENTRY_BUFSIZE, GFP_KERNEL); + + while (reg < DOCKRAM_ENTRIES) { + unsigned int len = DOCKRAM_ENTRY_SIZE - off; + + if (len > rsize) + len = rsize; + + ret = asus_dockram_read(client, reg, data); + if (ret < 0) { + if (!n_read) + n_read = ret; + break; + } + + val = copy_to_user(buf, data + 1 + off, len); + if (val == len) + return -EFAULT; + + *ppos += len; + n_read += len; + + if (len == rsize) + break; + + rsize -= len; + buf += len; + off = 0; + ++reg; + } + + kfree(data); + + return n_read; +} + +static int dockram_write_one(struct i2c_client *client, int reg, + const char __user *buf, size_t count) +{ + struct dockram_ec_data *priv = i2c_get_clientdata(client); + int ret; + + if (!count || count > DOCKRAM_ENTRY_SIZE) + return -EINVAL; + if (buf[0] != count - 1) + return -EINVAL; + + guard(mutex)(&priv->ctl_lock); + + priv->ctl_data[0] = (u8)count; + memcpy(priv->ctl_data + 1, buf, count); + ret = asus_dockram_write(client, reg, priv->ctl_data); + + return ret; +} + +static ssize_t dockram_write(struct file *filp, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct i2c_client *client = filp->private_data; + unsigned int reg; + loff_t off = *ppos; + int ret; + + if (off % DOCKRAM_ENTRY_SIZE != 0) + return -EINVAL; + + reg = off / DOCKRAM_ENTRY_SIZE; + if (reg >= DOCKRAM_ENTRIES) + return -EINVAL; + + ret = dockram_write_one(client, reg, buf, count); + + return ret < 0 ? ret : count; +} + +static const struct debugfs_short_fops dockram_fops = { + .read = dockram_read, + .write = dockram_write, + .llseek = default_llseek, +}; + +static int control_reg_get(void *client, u64 *val) +{ + return asus_dockram_access_ctl(client, val, 0, 0); +} + +static int control_reg_set(void *client, u64 val) +{ + return asus_dockram_access_ctl(client, NULL, ~0ull, val); +} + +DEFINE_DEBUGFS_ATTRIBUTE(control_reg_fops, control_reg_get, control_reg_set, "%016llx\n"); + +/** + * asus_dockram_debugfs_init - Register DockRAM debugfs. + * @client: Handle to the DockRAM device. + * @debugfs_root: Pointer to the root directory dentry. + * + * Creates a debugfs setup for DockRAM in the directory of the linked EC. + * The debugfs setup must be removed by the caller. + * + * Return: 0 on success or a negative error code on failure. + */ +void asus_dockram_debugfs_init(struct i2c_client *client, struct dentry *debugfs_root) +{ + struct dentry *dockram_dir; + + dockram_dir = debugfs_create_dir("dockram", debugfs_root); + + debugfs_create_file("control_reg", 0644, dockram_dir, client, &control_reg_fops); + debugfs_create_file("dockram", 0644, dockram_dir, client, &dockram_fops); +} +EXPORT_SYMBOL_GPL(asus_dockram_debugfs_init); + +static int asus_dockram_probe(struct i2c_client *client) +{ + struct dockram_ec_data *priv; + struct device *dev = &client->dev; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) + return dev_err_probe(dev, -ENXIO, + "I2C bus is missing required SMBus block mode support\n"); + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + i2c_set_clientdata(client, priv); + mutex_init(&priv->ctl_lock); + + return 0; +} + +static const struct of_device_id asus_dockram_ids[] = { + { .compatible = "asus,dockram" }, + { } +}; +MODULE_DEVICE_TABLE(of, asus_dockram_ids); + +static struct i2c_driver asus_dockram_driver = { + .driver = { + .name = "asus-dockram", + .of_match_table = of_match_ptr(asus_dockram_ids), + }, + .probe = asus_dockram_probe, +}; +module_i2c_driver(asus_dockram_driver); + +static void devm_i2c_device_release(struct device *dev, void *res) +{ + struct i2c_client **pdev = res; + struct i2c_client *child = *pdev; + + if (child) + put_device(&child->dev); +} + +static struct i2c_client *devm_i2c_device_get_by_phandle(struct device *dev, + const char *name, + int index) +{ + struct device_node *np; + struct i2c_client **pdev; + + pdev = devres_alloc(devm_i2c_device_release, sizeof(*pdev), + GFP_KERNEL); + if (!pdev) + return ERR_PTR(-ENOMEM); + + np = of_parse_phandle(dev_of_node(dev), name, index); + if (!np) { + devres_free(pdev); + dev_err(dev, "can't resolve phandle %s: %d\n", name, index); + return ERR_PTR(-ENODEV); + } + + *pdev = of_find_i2c_device_by_node(np); + of_node_put(np); + + if (!*pdev) { + devres_free(pdev); + return ERR_PTR(-EPROBE_DEFER); + } + + devres_add(dev, pdev); + + return *pdev; +} + +/** + * devm_asus_dockram_get - Device-managed request of DockRAM via device phandle. + * @parent: Parent device which requests the DockRAM device. + * + * Request the DockRAM device by phandle from the parent's device-tree node. + * The DockRAM device phandle will be automatically released and DockRAM will be + * detached on parent driver detach. + * + * Return: Pointer to the DockRAM I2C device on success, or an ERR_PTR on failure. + */ +struct i2c_client *devm_asus_dockram_get(struct device *parent) +{ + struct i2c_client *dockram = + devm_i2c_device_get_by_phandle(parent, "asus,dockram", 0); + + if (IS_ERR(dockram)) + return dockram; + if (!dockram->dev.driver) + return ERR_PTR(-EPROBE_DEFER); + if (dockram->dev.driver != &asus_dockram_driver.driver) + return ERR_PTR(-EBUSY); + + return dockram; +} +EXPORT_SYMBOL_GPL(devm_asus_dockram_get); + +MODULE_AUTHOR("Michał Mirosław "); +MODULE_DESCRIPTION("ASUS Transformer's dockram driver"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/mfd/asus-ec.h b/include/linux/mfd/asus-ec.h new file mode 100644 index 000000000000..6a36313b9ebd --- /dev/null +++ b/include/linux/mfd/asus-ec.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef __MISC_ASUS_EC_H +#define __MISC_ASUS_EC_H + +struct i2c_client; + +#define DOCKRAM_ENTRIES 0x100 +#define DOCKRAM_ENTRY_SIZE 32 +#define DOCKRAM_ENTRY_BUFSIZE (DOCKRAM_ENTRY_SIZE + 1) + +/* control register [0x0A] layout */ +#define ASUSEC_CTL_SIZE 8 + +#define ASUSEC_DOCKRAM_CONTROL 0x0a + +/* dockram comm */ +int asus_dockram_read(struct i2c_client *client, int reg, char *buf); +int asus_dockram_write(struct i2c_client *client, int reg, const char *buf); +int asus_dockram_access_ctl(struct i2c_client *client, + u64 *out, u64 mask, u64 xor); +struct i2c_client *devm_asus_dockram_get(struct device *parent); +void asus_dockram_debugfs_init(struct i2c_client *client, + struct dentry *debugfs_root); +#endif /* __MISC_ASUS_EC_H */ -- 2.51.0