Hi Benson,
> This patch adds support for the Cypress APA Smbus Trackpad type,
> which uses a modified register map that fits within the
> limitations of the smbus protocol.
>
> Devices that use this protocol include:
> CYTRA-116001-00 - Samsung Series 5 550 Chromebook trackpad
> CYTRA-103002-00 - Acer C7 Chromebook trackpad
>
> Signed-off-by: Dudley Du <d...@cypress.com>
> Signed-off-by: Benson Leung <ble...@chromium.org>
> Reviewed-by: Daniel Kurtz <djku...@chromium.org>
> ---
> drivers/input/mouse/cyapa.c | 184
> ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 179 insertions(+), 5 deletions(-)
Looking good, thank you. Just a really tiny style comment inline.
> diff --git a/drivers/input/mouse/cyapa.c b/drivers/input/mouse/cyapa.c
> index 1a14688..4ce0cb4 100644
> --- a/drivers/input/mouse/cyapa.c
> +++ b/drivers/input/mouse/cyapa.c
> @@ -208,6 +208,7 @@ struct cyapa {
> char phys[32]; /* device physical location */
> int irq;
> bool irq_wake; /* irq wake is enabled */
> + bool smbus;
>
> /* read from query data region. */
> char product_id[16];
> @@ -229,6 +230,60 @@ struct cyapa_cmd_len {
> u8 len;
> };
>
> +#define CYAPA_ADAPTER_FUNC_NONE 0
> +#define CYAPA_ADAPTER_FUNC_I2C 1
> +#define CYAPA_ADAPTER_FUNC_SMBUS 2
> +#define CYAPA_ADAPTER_FUNC_BOTH 3
> +
> +/*
> + * macros for SMBus communication
> + */
> +#define SMBUS_READ 0x01
> +#define SMBUS_WRITE 0x00
> +#define SMBUS_ENCODE_IDX(cmd, idx) ((cmd) | (((idx) & 0x03) << 1))
> +#define SMBUS_ENCODE_RW(cmd, rw) ((cmd) | ((rw) & 0x01))
> +#define SMBUS_BYTE_BLOCK_CMD_MASK 0x80
> +#define SMBUS_GROUP_BLOCK_CMD_MASK 0x40
> +
> + /* for byte read/write command */
> +#define CMD_RESET 0
> +#define CMD_POWER_MODE 1
> +#define CMD_DEV_STATUS 2
> +#define SMBUS_BYTE_CMD(cmd) (((cmd) & 0x3f) << 1)
> +#define CYAPA_SMBUS_RESET SMBUS_BYTE_CMD(CMD_RESET)
> +#define CYAPA_SMBUS_POWER_MODE SMBUS_BYTE_CMD(CMD_POWER_MODE)
> +#define CYAPA_SMBUS_DEV_STATUS SMBUS_BYTE_CMD(CMD_DEV_STATUS)
> +
> + /* for group registers read/write command */
> +#define REG_GROUP_DATA 0
> +#define REG_GROUP_CMD 2
> +#define REG_GROUP_QUERY 3
> +#define SMBUS_GROUP_CMD(grp) (0x80 | (((grp) & 0x07) << 3))
> +#define CYAPA_SMBUS_GROUP_DATA SMBUS_GROUP_CMD(REG_GROUP_DATA)
> +#define CYAPA_SMBUS_GROUP_CMD SMBUS_GROUP_CMD(REG_GROUP_CMD)
> +#define CYAPA_SMBUS_GROUP_QUERY SMBUS_GROUP_CMD(REG_GROUP_QUERY)
> +
> + /* for register block read/write command */
> +#define CMD_BL_STATUS 0
> +#define CMD_BL_HEAD 1
> +#define CMD_BL_CMD 2
> +#define CMD_BL_DATA 3
> +#define CMD_BL_ALL 4
> +#define CMD_BLK_PRODUCT_ID 5
> +#define CMD_BLK_HEAD 6
> +#define SMBUS_BLOCK_CMD(cmd) (0xc0 | (((cmd) & 0x1f) << 1))
> +
> +/* register block read/write command in bootloader mode */
> +#define CYAPA_SMBUS_BL_STATUS SMBUS_BLOCK_CMD(CMD_BL_STATUS)
> +#define CYAPA_SMBUS_BL_HEAD SMBUS_BLOCK_CMD(CMD_BL_HEAD)
> +#define CYAPA_SMBUS_BL_CMD SMBUS_BLOCK_CMD(CMD_BL_CMD)
> +#define CYAPA_SMBUS_BL_DATA SMBUS_BLOCK_CMD(CMD_BL_DATA)
> +#define CYAPA_SMBUS_BL_ALL SMBUS_BLOCK_CMD(CMD_BL_ALL)
> +
> +/* register block read/write command in operational mode */
> +#define CYAPA_SMBUS_BLK_PRODUCT_ID SMBUS_BLOCK_CMD(CMD_BLK_PRODUCT_ID)
> +#define CYAPA_SMBUS_BLK_HEAD SMBUS_BLOCK_CMD(CMD_BLK_HEAD)
> +
> static const struct cyapa_cmd_len cyapa_i2c_cmds[] = {
> { CYAPA_OFFSET_SOFT_RESET, 1 },
> { REG_OFFSET_COMMAND_BASE + 1, 1 },
> @@ -245,6 +300,22 @@ static const struct cyapa_cmd_len cyapa_i2c_cmds[] = {
> { REG_OFFSET_DATA_BASE, 32 }
> };
>
> +static const struct cyapa_cmd_len cyapa_smbus_cmds[] = {
> + { CYAPA_SMBUS_RESET, 1 },
> + { CYAPA_SMBUS_POWER_MODE, 1 },
> + { CYAPA_SMBUS_DEV_STATUS, 1 },
> + { CYAPA_SMBUS_GROUP_DATA, sizeof(struct cyapa_reg_data) },
> + { CYAPA_SMBUS_GROUP_CMD, 2 },
> + { CYAPA_SMBUS_GROUP_QUERY, QUERY_DATA_SIZE },
> + { CYAPA_SMBUS_BL_STATUS, 3 },
> + { CYAPA_SMBUS_BL_HEAD, 16 },
> + { CYAPA_SMBUS_BL_CMD, 16 },
> + { CYAPA_SMBUS_BL_DATA, 16 },
> + { CYAPA_SMBUS_BL_ALL, 32 },
> + { CYAPA_SMBUS_BLK_PRODUCT_ID, PRODUCT_ID_SIZE },
> + { CYAPA_SMBUS_BLK_HEAD, 16 },
> +};
> +
> static ssize_t cyapa_i2c_reg_read_block(struct cyapa *cyapa, u8 reg, size_t
> len,
> u8 *values)
> {
> @@ -257,26 +328,96 @@ static ssize_t cyapa_i2c_reg_write_block(struct cyapa
> *cyapa, u8 reg,
> return i2c_smbus_write_i2c_block_data(cyapa->client, reg, len, values);
> }
>
> +/*
> + * cyapa_smbus_read_block - perform smbus block read command
> + * @cyapa - private data structure of the driver
> + * @cmd - the properly encoded smbus command
> + * @len - expected length of smbus command result
> + * @values - buffer to store smbus command result
> + *
> + * Returns negative errno, else the number of bytes written.
> + *
> + * Note:
> + * In trackpad device, the memory block allocated for I2C register map
> + * is 256 bytes, so the max read block for I2C bus is 256 bytes.
> + */
> +static ssize_t cyapa_smbus_read_block(struct cyapa *cyapa, u8 cmd, size_t
> len,
> + u8 *values)
> +{
> + ssize_t ret;
> + u8 index;
> + u8 smbus_cmd;
> + u8 *buf;
> + struct i2c_client *client = cyapa->client;
> + struct device *dev = &client->dev;
> +
> + if (!(SMBUS_BYTE_BLOCK_CMD_MASK & cmd))
> + return -EINVAL;
> +
> + if (SMBUS_GROUP_BLOCK_CMD_MASK & cmd) {
> + /* read specific block registers command. */
> + smbus_cmd = SMBUS_ENCODE_RW(cmd, SMBUS_READ);
> + ret = i2c_smbus_read_block_data(client, smbus_cmd, values);
> + goto out;
> + }
> +
> + ret = 0;
> + for (index = 0; index * I2C_SMBUS_BLOCK_MAX < len; index++) {
> + smbus_cmd = SMBUS_ENCODE_IDX(cmd, index);
> + smbus_cmd = SMBUS_ENCODE_RW(smbus_cmd, SMBUS_READ);
> + buf = values + I2C_SMBUS_BLOCK_MAX * index;
> + ret = i2c_smbus_read_block_data(client, smbus_cmd, buf);
> + if (ret < 0)
> + goto out;
> + }
> +
> +out:
> +
> + return (ret > 0) ? len : ret;
> +}
> +
> static s32 cyapa_read_byte(struct cyapa *cyapa, u8 cmd_idx)
> {
> - u8 cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> + struct device *dev = &cyapa->client->dev;
> + u8 cmd;
>
> + if (cyapa->smbus) {
> + cmd = cyapa_smbus_cmds[cmd_idx].cmd;
> + cmd = SMBUS_ENCODE_RW(cmd, SMBUS_READ);
> + } else {
> + cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> + }
> return i2c_smbus_read_byte_data(cyapa->client, cmd);
> }
>
> static s32 cyapa_write_byte(struct cyapa *cyapa, u8 cmd_idx, u8 value)
> {
> - u8 cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> + struct device *dev = &cyapa->client->dev;
> + u8 cmd;
>
> + if (cyapa->smbus) {
> + cmd = cyapa_smbus_cmds[cmd_idx].cmd;
> + cmd = SMBUS_ENCODE_RW(cmd, SMBUS_WRITE);
> + } else {
> + cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> + }
> return i2c_smbus_write_byte_data(cyapa->client, cmd, value);
> }
>
> static ssize_t cyapa_read_block(struct cyapa *cyapa, u8 cmd_idx, u8 *values)
> {
> - u8 cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> - size_t len = cyapa_i2c_cmds[cmd_idx].len;
> + u8 cmd;
> + size_t len;
>
> - return cyapa_i2c_reg_read_block(cyapa, cmd, len, values);
> + if (cyapa->smbus) {
> + cmd = cyapa_smbus_cmds[cmd_idx].cmd;
> + len = cyapa_smbus_cmds[cmd_idx].len;
> + return cyapa_smbus_read_block(cyapa, cmd, len, values);
> + } else {
> + cmd = cyapa_i2c_cmds[cmd_idx].cmd;
> + len = cyapa_i2c_cmds[cmd_idx].len;
> + return cyapa_i2c_reg_read_block(cyapa, cmd, len, values);
> + }
> }
>
> /*
> @@ -298,6 +439,16 @@ static int cyapa_get_state(struct cyapa *cyapa)
> */
> ret = cyapa_i2c_reg_read_block(cyapa, BL_HEAD_OFFSET, BL_STATUS_SIZE,
> status);
> +
> + /*
> + * On smbus systems in OP mode, the i2c_reg_read will fail with
> + * -ETIMEDOUT. In this case, try again using the smbus equivalent
> + * command. This should return a BL_HEAD indicating CYAPA_STATE_OP.
> + */
> + if (cyapa->smbus && (ret == -ETIMEDOUT || ret == -ENXIO)) {
> + ret = cyapa_read_block(cyapa, CYAPA_CMD_BL_STATUS, status);
> + }
It is customary to skip brackets for single expressions.
> +
> if (ret != BL_STATUS_SIZE)
> goto error;
>
> @@ -594,6 +745,19 @@ out:
> return IRQ_HANDLED;
> }
>
> +static u8 cyapa_check_adapter_functionality(struct i2c_client *client)
> +{
> + u8 ret = CYAPA_ADAPTER_FUNC_NONE;
> +
> + if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
> + ret |= CYAPA_ADAPTER_FUNC_I2C;
> + if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> + I2C_FUNC_SMBUS_BLOCK_DATA |
> + I2C_FUNC_SMBUS_I2C_BLOCK))
> + ret |= CYAPA_ADAPTER_FUNC_SMBUS;
> + return ret;
> +}
> +
> static int cyapa_create_input_dev(struct cyapa *cyapa)
> {
> struct device *dev = &cyapa->client->dev;
> @@ -668,9 +832,16 @@ static int cyapa_probe(struct i2c_client *client,
> const struct i2c_device_id *dev_id)
> {
> int ret;
> + u8 adapter_func;
> struct cyapa *cyapa;
> struct device *dev = &client->dev;
>
> + adapter_func = cyapa_check_adapter_functionality(client);
> + if (adapter_func == CYAPA_ADAPTER_FUNC_NONE) {
> + dev_err(dev, "not a supported I2C/SMBus adapter\n");
> + return -EIO;
> + }
> +
> cyapa = kzalloc(sizeof(struct cyapa), GFP_KERNEL);
> if (!cyapa) {
> dev_err(dev, "allocate memory for cyapa failed\n");
> @@ -683,6 +854,9 @@ static int cyapa_probe(struct i2c_client *client,
> sprintf(cyapa->phys, "i2c-%d-%04x/input0", client->adapter->nr,
> client->addr);
>
> + /* i2c isn't supported, set smbus */
> + if (adapter_func == CYAPA_ADAPTER_FUNC_SMBUS)
> + cyapa->smbus = true;
> cyapa->state = CYAPA_STATE_NO_DEVICE;
> ret = cyapa_check_is_operational(cyapa);
> if (ret) {
> --
> 1.8.1
>
Thanks,
Henrik
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