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

From: Oreste Salerno
Date: Thu Jan 21 2016 - 15:44:39 EST

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On Thu, Jan 21, 2016 at 11:35:46AM -0800, Dmitry Torokhov wrote:
> 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@xxxxxxxxxx>
> > > ---
> > > .../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?

No, if this is handled in some other way I guess it won't be necessary.
I can make it optional.

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

Yes, I can do that in a followup patch if that's ok.

>
> > > + - 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?
>

To be honest I had not tried it yet. I've just tried and it works ok.

> >
> > 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.
>

Something like "Cypress TTSP touchscreen"? Same naming used in the Kconfig.

> Thanks.
>
> --
> Dmitry

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