On Thu, Nov 5, 2020 at 3:32 AM Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx> wrote:
>
> The mcp2221 driver GPIO output handling has has several issues.
>
> * A wrong value is used for the GPIO direction.
>
> * Wrong offsets are calculated for some GPIO set value/set direction
> operations, when offset is larger than 0.
>
> This has been fixed by introducing proper manifest constants for the
> direction encoding, and using 'offsetof' when calculating GPIO
> register offsets.
>
> The updated driver has been tested with the Sparx5 pcb134/pcb135
> board, which has the mcp2221 device with several (output) GPIO's.
>
> Signed-off-by: Lars Povlsen <lars.povlsen@xxxxxxxxxxxxx>
> ---
> drivers/hid/hid-mcp2221.c | 48 +++++++++++++++++++++++++++++++--------
> 1 file changed, 39 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/hid/hid-mcp2221.c b/drivers/hid/hid-mcp2221.c
> index 0d27ccb55dd9..4211b9839209 100644
> --- a/drivers/hid/hid-mcp2221.c
> +++ b/drivers/hid/hid-mcp2221.c
> @@ -49,6 +49,36 @@ enum {
> MCP2221_ALT_F_NOT_GPIOD = 0xEF,
> };
>
> +/* MCP GPIO direction encoding */
> +enum {
> + MCP2221_DIR_OUT = 0x00,
> + MCP2221_DIR_IN = 0x01,
> +};
> +
> +#define MCP_NGPIO 4
> +
> +/* MCP GPIO set command layout */
> +struct mcp_set_gpio {
> + u8 cmd;
> + u8 dummy;
> + struct {
> + u8 change_value;
> + u8 value;
> + u8 change_direction;
> + u8 direction;
> + } gpio[MCP_NGPIO];
> +} __packed;
> +
> +/* MCP GPIO get command layout */
> +struct mcp_get_gpio {
> + u8 cmd;
> + u8 dummy;
> + struct {
> + u8 direction;
> + u8 value;
> + } gpio[MCP_NGPIO];
> +} __packed;
> +
> /*
> * There is no way to distinguish responses. Therefore next command
> * is sent only after response to previous has been received. Mutex
> @@ -542,7 +572,7 @@ static int mcp_gpio_get(struct gpio_chip *gc,
>
> mcp->txbuf[0] = MCP2221_GPIO_GET;
>
> - mcp->gp_idx = (offset + 1) * 2;
> + mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset].value);
>
> mutex_lock(&mcp->lock);
> ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
> @@ -559,7 +589,7 @@ static void mcp_gpio_set(struct gpio_chip *gc,
> memset(mcp->txbuf, 0, 18);
> mcp->txbuf[0] = MCP2221_GPIO_SET;
>
> - mcp->gp_idx = ((offset + 1) * 4) - 1;
> + mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].value);
>
> mcp->txbuf[mcp->gp_idx - 1] = 1;
> mcp->txbuf[mcp->gp_idx] = !!value;
> @@ -575,7 +605,7 @@ static int mcp_gpio_dir_set(struct mcp2221 *mcp,
> memset(mcp->txbuf, 0, 18);
> mcp->txbuf[0] = MCP2221_GPIO_SET;
>
> - mcp->gp_idx = (offset + 1) * 5;
> + mcp->gp_idx = offsetof(struct mcp_set_gpio, gpio[offset].direction);
>
> mcp->txbuf[mcp->gp_idx - 1] = 1;
> mcp->txbuf[mcp->gp_idx] = val;
> @@ -590,7 +620,7 @@ static int mcp_gpio_direction_input(struct gpio_chip *gc,
> struct mcp2221 *mcp = gpiochip_get_data(gc);
>
> mutex_lock(&mcp->lock);
> - ret = mcp_gpio_dir_set(mcp, offset, 0);
> + ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_IN);
> mutex_unlock(&mcp->lock);
>
> return ret;
> @@ -603,7 +633,7 @@ static int mcp_gpio_direction_output(struct gpio_chip *gc,
> struct mcp2221 *mcp = gpiochip_get_data(gc);
>
> mutex_lock(&mcp->lock);
> - ret = mcp_gpio_dir_set(mcp, offset, 1);
> + ret = mcp_gpio_dir_set(mcp, offset, MCP2221_DIR_OUT);
> mutex_unlock(&mcp->lock);
>
> /* Can't configure as output, bailout early */
> @@ -623,7 +653,7 @@ static int mcp_gpio_get_direction(struct gpio_chip *gc,
>
> mcp->txbuf[0] = MCP2221_GPIO_GET;
>
> - mcp->gp_idx = (offset + 1) * 2;
> + mcp->gp_idx = offsetof(struct mcp_get_gpio, gpio[offset].direction);
>
> mutex_lock(&mcp->lock);
> ret = mcp_send_data_req_status(mcp, mcp->txbuf, 1);
> @@ -632,7 +662,7 @@ static int mcp_gpio_get_direction(struct gpio_chip *gc,
> if (ret)
> return ret;
>
> - if (mcp->gpio_dir)
> + if (mcp->gpio_dir == MCP2221_DIR_IN)
> return GPIO_LINE_DIRECTION_IN;
>
> return GPIO_LINE_DIRECTION_OUT;
> @@ -758,7 +788,7 @@ static int mcp2221_raw_event(struct hid_device *hdev,
> mcp->status = -ENOENT;
> } else {
> mcp->status = !!data[mcp->gp_idx];
> - mcp->gpio_dir = !!data[mcp->gp_idx + 1];
> + mcp->gpio_dir = data[mcp->gp_idx + 1];
> }
> break;
> default:
> @@ -860,7 +890,7 @@ static int mcp2221_probe(struct hid_device *hdev,
> mcp->gc->get_direction = mcp_gpio_get_direction;
> mcp->gc->set = mcp_gpio_set;
> mcp->gc->get = mcp_gpio_get;
> - mcp->gc->ngpio = 4;
> + mcp->gc->ngpio = MCP_NGPIO;
> mcp->gc->base = -1;
> mcp->gc->can_sleep = 1;
> mcp->gc->parent = &hdev->dev;
> --
> 2.25.1
>
Reviewed-by: Rishi Gupta <gupt21@xxxxxxxxx>
Regards,
Rishi
