Re: [PATCH v4 3/4] Input: cyttsp - switch to using device properties

Dmitry Torokhov
2016-01-21T19:35:56Z

On Thu, Jan 21, 2016 at 08:25:53PM +0100, Oreste Salerno wrote:
> On Thu, Jan 21, 2016 at 08:21:15PM +0100, Oreste Salerno wrote:
> > Drop support for platform data passed via a C-structure and switch to
> > device properties instead, which should make the driver compatible
> > with all platforms: OF, ACPI and static boards. Static boards should
> > use property sets to communicate device parameters to the driver.
> >
> > Signed-off-by: Oreste Salerno <oreste.salerno@tomtom.com>
> > ---
> > .../bindings/input/touchscreen/cyttsp.txt | 95 ++++++++++++
> > drivers/input/touchscreen/cyttsp_core.c | 167 ++++++++++++++-------
> > drivers/input/touchscreen/cyttsp_core.h | 10 +-
> > drivers/input/touchscreen/cyttsp_i2c.c | 10 --
> > drivers/input/touchscreen/cyttsp_spi.c | 10 --
> > include/linux/input/cyttsp.h | 15 --
> > 6 files changed, 213 insertions(+), 94 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> >
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt b/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> > new file mode 100644
> > index 0000000..b0fccae
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/cyttsp.txt
> > @@ -0,0 +1,95 @@
> > +* Cypress cyttsp touchscreen controller
> > +
> > +Required properties:
> > + - compatible : must be "cypress,cyttsp-i2c" or "cypress,cyttsp-spi"
> > + - reg : Device I2C address or SPI chip select number
> > + - spi-max-frequency : Maximum SPI clocking speed of the device (for cyttsp-spi)
> > + - interrupt-parent : the phandle for the gpio controller
> > + (see interrupt binding[0]).
> > + - interrupts : (gpio) interrupt to which the chip is connected
> > + (see interrupt binding[0]).
> > + - reset-gpios : the reset gpio the chip is connected to
> > + (see GPIO binding[1] for more details).

Why do we have to have reset gpio available? If platform firmware powers up and
resets the controller and keeps it's power do they have to expose reset
gpio?

Also, maybe you also need to wire up power supply support (maybe a
follwup patch)?

> > + - touchscreen-size-x : horizontal resolution of touchscreen (in pixels)
> > + - touchscreen-size-y : vertical resolution of touchscreen (in pixels)

Do these have to be mandatory? Will not the driver work without them?

>
> I decided to explicitly specify the generic touchscreen properties here (instead of
> referring to touchscreen.txt) because not all properties listed in touchscreen.txt
> are actually parsed by the driver.

Fair enough.

Thanks.

>
> > + - bootloader-key : the 8-byte bootloader key that is required to switch
> > + the chip from bootloader mode (default mode) to
> > + application mode.
> > + This property has to be specified as an array of 8
> > + '/bits/ 8' values.
> > +
> > +Optional properties:
> > + - touchscreen-fuzz-x : horizontal noise value of the absolute input device
> > + (in pixels)
> > + - touchscreen-fuzz-y : vertical noise value of the absolute input device
> > + (in pixels)
> > + - active-distance : the distance in pixels beyond which a touch must move
> > + before movement is detected and reported by the device.
> > + Valid values: 0-15.
> > + - active-interval-ms : the minimum period in ms between consecutive
> > + scanning/processing cycles when the chip is in active mode.
> > + Valid values: 0-255.
> > + - lowpower-interval-ms : the minimum period in ms between consecutive
> > + scanning/processing cycles when the chip is in low-power mode.
> > + Valid values: 0-2550
> > + - touch-timeout-ms : minimum time in ms spent in the active power state while no
> > + touches are detected before entering low-power mode.
> > + Valid values: 0-2550
> > + - use-handshake : enable register-based handshake (boolean). This should
> > + only be used if the chip is configured to use 'blocking
> > + communication with timeout' (in this case the device
> > + generates an interrupt at the end of every
> > + scanning/processing cycle).
> > +
> > +[0]: Documentation/devicetree/bindings/interrupt-controller/interrupts.txt
> > +[1]: Documentation/devicetree/bindings/gpio/gpio.txt
> > +
> > +Example:
> > + &i2c1 {
> > + /* ... */
> > + cyttsp@a {
> > + compatible = "cypress,cyttsp-i2c";
> > + reg = <0xa>;
> > + interrupt-parent = <&gpio0>;
> > + interrupts = <28 0>;
> > + reset-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
> > +
> > + touchscreen-size-x = <800>;
> > + touchscreen-size-y = <480>;
> > + touchscreen-fuzz-x = <4>;
> > + touchscreen-fuzz-y = <7>;
> > +
> > + bootloader-key = /bits/ 8 <0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08>;
> > + active-distance = <8>;
> > + active-interval-ms = <0>;
> > + lowpower-interval-ms = <200>;
> > + touch-timeout-ms = <100>;
> > + };
> > +
> > + /* ... */
> > + };
> > +
> > + &mcspi1 {
> > + /* ... */
> > + cyttsp@0 {
> > + compatible = "cypress,cyttsp-spi";
> > + spi-max-frequency = <6000000>;
> > + reg = <0>;
> > + interrupt-parent = <&gpio0>;
> > + interrupts = <28 0>;
> > + reset-gpios = <&gpio3 4 GPIO_ACTIVE_LOW>;
> > +
> > + touchscreen-size-x = <800>;
> > + touchscreen-size-y = <480>;
> > + touchscreen-fuzz-x = <4>;
> > + touchscreen-fuzz-y = <7>;
> > +
> > + bootloader-key = /bits/ 8 <0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08>;
> > + active-distance = <8>;
> > + active-interval-ms = <0>;
> > + lowpower-interval-ms = <200>;
> > + touch-timeout-ms = <100>;
> > + };
> > +
> > + /* ... */
> > + };
> > diff --git a/drivers/input/touchscreen/cyttsp_core.c b/drivers/input/touchscreen/cyttsp_core.c
> > index 10379bc..92b459d 100644
> > --- a/drivers/input/touchscreen/cyttsp_core.c
> > +++ b/drivers/input/touchscreen/cyttsp_core.c
> > @@ -30,9 +30,12 @@
> > #include <linux/delay.h>
> > #include <linux/input.h>
> > #include <linux/input/mt.h>
> > +#include <linux/input/touchscreen.h>
> > #include <linux/gpio.h>
> > #include <linux/interrupt.h>
> > #include <linux/slab.h>
> > +#include <linux/property.h>
> > +#include <linux/gpio/consumer.h>
> >
> > #include "cyttsp_core.h"
> >
> > @@ -57,6 +60,7 @@
> > #define CY_DELAY_DFLT 20 /* ms */
> > #define CY_DELAY_MAX 500
> > #define CY_ACT_DIST_DFLT 0xF8
> > +#define CY_ACT_DIST_MASK 0x0F
> > #define CY_HNDSHK_BIT 0x80
> > /* device mode bits */
> > #define CY_OPERATE_MODE 0x00
> > @@ -120,7 +124,7 @@ static int ttsp_send_command(struct cyttsp *ts, u8 cmd)
> >
> > static int cyttsp_handshake(struct cyttsp *ts)
> > {
> > - if (ts->pdata->use_hndshk)
> > + if (ts->use_hndshk)
> > return ttsp_send_command(ts,
> > ts->xy_data.hst_mode ^ CY_HNDSHK_BIT);
> >
> > @@ -142,9 +146,9 @@ static int cyttsp_exit_bl_mode(struct cyttsp *ts)
> > u8 bl_cmd[sizeof(bl_command)];
> >
> > memcpy(bl_cmd, bl_command, sizeof(bl_command));
> > - if (ts->pdata->bl_keys)
> > + if (ts->bl_keys)
> > memcpy(&bl_cmd[sizeof(bl_command) - CY_NUM_BL_KEYS],
> > - ts->pdata->bl_keys, CY_NUM_BL_KEYS);
> > + ts->bl_keys, CY_NUM_BL_KEYS);
> >
> > error = ttsp_write_block_data(ts, CY_REG_BASE,
> > sizeof(bl_cmd), bl_cmd);
> > @@ -217,14 +221,14 @@ static int cyttsp_set_sysinfo_regs(struct cyttsp *ts)
> > {
> > int retval = 0;
> >
> > - if (ts->pdata->act_intrvl != CY_ACT_INTRVL_DFLT ||
> > - ts->pdata->tch_tmout != CY_TCH_TMOUT_DFLT ||
> > - ts->pdata->lp_intrvl != CY_LP_INTRVL_DFLT) {
> > + if (ts->act_intrvl != CY_ACT_INTRVL_DFLT ||
> > + ts->tch_tmout != CY_TCH_TMOUT_DFLT ||
> > + ts->lp_intrvl != CY_LP_INTRVL_DFLT) {
> >
> > u8 intrvl_ray[] = {
> > - ts->pdata->act_intrvl,
> > - ts->pdata->tch_tmout,
> > - ts->pdata->lp_intrvl
> > + ts->act_intrvl,
> > + ts->tch_tmout,
> > + ts->lp_intrvl
> > };
> >
> > /* set intrvl registers */
> > @@ -263,7 +267,7 @@ out:
> >
> > static int cyttsp_act_dist_setup(struct cyttsp *ts)
> > {
> > - u8 act_dist_setup = ts->pdata->act_dist;
> > + u8 act_dist_setup = ts->act_dist;
> >
> > /* Init gesture; active distance setup */
> > return ttsp_write_block_data(ts, CY_REG_ACT_DIST,
> > @@ -528,45 +532,107 @@ static void cyttsp_close(struct input_dev *dev)
> > cyttsp_disable(ts);
> > }
> >
> > +static int cyttsp_parse_properties(struct cyttsp *ts)
> > +{
> > + struct device *dev = ts->dev;
> > + u32 dt_value;
> > + int ret;
> > +
> > + ts->bl_keys = devm_kzalloc(dev, CY_NUM_BL_KEYS, GFP_KERNEL);
> > + if (!ts->bl_keys)
> > + return -ENOMEM;
> > +
> > + /* Set some default values */
> > + ts->use_hndshk = false;
> > + ts->act_dist = CY_ACT_DIST_DFLT;
> > + ts->act_intrvl = CY_ACT_INTRVL_DFLT;
> > + ts->tch_tmout = CY_TCH_TMOUT_DFLT;
> > + ts->lp_intrvl = CY_LP_INTRVL_DFLT;
> > +
> > + ret = device_property_read_u8_array(dev, "bootloader-key",
> > + ts->bl_keys, CY_NUM_BL_KEYS);
> > + if (ret) {
> > + dev_err(dev,
> > + "bootloader-key property could not be retrieved\n");
> > + return ret;
> > + }
> > +
> > + ts->use_hndshk = device_property_present(dev, "use-handshake");
> > +
> > + if (!device_property_read_u32(dev, "active-distance", &dt_value)) {
> > + if (dt_value > 15) {
> > + dev_err(dev, "active-distance (%u) must be [0-15]\n",
> > + dt_value);
> > + return -EINVAL;
> > + }
> > + ts->act_dist &= ~CY_ACT_DIST_MASK;
> > + ts->act_dist |= dt_value;
> > + }
> > +
> > + if (!device_property_read_u32(dev, "active-interval-ms", &dt_value)) {
> > + if (dt_value > 255) {
> > + dev_err(dev, "active-interval-ms (%u) must be [0-255]\n",
> > + dt_value);
> > + return -EINVAL;
> > + }
> > + ts->act_intrvl = dt_value;
> > + }
> > +
> > + if (!device_property_read_u32(dev, "lowpower-interval-ms", &dt_value)) {
> > + if (dt_value > 2550) {
> > + dev_err(dev, "lowpower-interval-ms (%u) must be [0-2550]\n",
> > + dt_value);
> > + return -EINVAL;
> > + }
> > + /* Register value is expressed in 0.01s / bit */
> > + ts->lp_intrvl = dt_value / 10;
> > + }
> > +
> > + if (!device_property_read_u32(dev, "touch-timeout-ms", &dt_value)) {
> > + if (dt_value > 2550) {
> > + dev_err(dev, "touch-timeout-ms (%u) must be [0-2550]\n",
> > + dt_value);
> > + return -EINVAL;
> > + }
> > + /* Register value is expressed in 0.01s / bit */
> > + ts->tch_tmout = dt_value/10;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > struct cyttsp *cyttsp_probe(const struct cyttsp_bus_ops *bus_ops,
> > struct device *dev, int irq, size_t xfer_buf_size)
> > {
> > - const struct cyttsp_platform_data *pdata = dev_get_platdata(dev);
> > struct cyttsp *ts;
> > struct input_dev *input_dev;
> > int error;
> >
> > - if (!pdata || !pdata->name || irq <= 0) {
> > - error = -EINVAL;
> > - goto err_out;
> > - }
> > -
> > ts = devm_kzalloc(dev, sizeof(*ts) + xfer_buf_size, GFP_KERNEL);
> > input_dev = devm_input_allocate_device(dev);
> > - if (!ts || !input_dev) {
> > - error = -ENOMEM;
> > - goto err_out;
> > - }
> > + if (!ts || !input_dev)
> > + return ERR_PTR(-ENOMEM);
> >
> > ts->dev = dev;
> > ts->input = input_dev;
> > - ts->pdata = dev_get_platdata(dev);
> > ts->bus_ops = bus_ops;
> > ts->irq = irq;
> >
> > + ts->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
> > + if (IS_ERR(ts->reset_gpio)) {
> > + error = PTR_ERR(ts->reset_gpio);
> > + dev_err(dev, "Failed to request reset gpio, error %d\n", error);
> > + return ERR_PTR(error);
> > + }
> > +
> > + error = cyttsp_parse_properties(ts);
> > + if (error)
> > + return ERR_PTR(error);
> > +
> > init_completion(&ts->bl_ready);
> > snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));
> >
> > - if (pdata->init) {
> > - error = pdata->init();
> > - if (error) {
> > - dev_err(ts->dev, "platform init failed, err: %d\n",
> > - error);
> > - goto err_out;
> > - }
> > - }
> > -
> > - input_dev->name = pdata->name;
> > + input_dev->name = "cyttsp";

Is there a friendlier name we could use? It is exported in
/proc/bus/input/devices and usually is more descriptive.

Thanks.

--
Dmitry