Hi Ramesh,
On Wed, Oct 12, 2016 at 4:10 PM, Ramesh Shanmugasundaram
<ramesh.shanmugasundaram@xxxxxxxxxxxxxx> wrote:
> This patch adds driver support for MAX2175 chip. This is Maxim
> Integrated's RF to Bits tuner front end chip designed for software-defined
> radio solutions. This driver exposes the tuner as a sub-device instance
> with standard and custom controls to configure the device.
>
> Signed-off-by: Ramesh Shanmugasundaram < for your patch!amesh.shanmugasundaram@xxxxxxxxxxxxxx>
Thanks for your patch!
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/max2175.txt
> @@ -0,0 +1,60 @@
> +Maxim Integrated MAX2175 RF to Bits tuner
> +-----------------------------------------
> +
> +The MAX2175 IC is an advanced analog/digital hybrid-radio receiver with
> +RF to Bits® front-end designed for software-defined radio solutions.
> +
> +Required properties:
> +--------------------
> +- compatible: "maxim,max2175" for MAX2175 RF-to-bits tuner.
> +- clocks: phandle to the fixed xtal clock.
> +- clock-names: name of the fixed xtal clock.
> +- port: video interface child port node of a tuner that defines the local
> + and remote endpoints. The remote endpoint is assumed to be an SDR device
> + that is capable of receiving the digital samples from the tuner.
> +
> +Optional properties:
> +--------------------
> +- maxim,slave : empty property indicates this is a slave of another
> + master tuner. This is used to define two tuners in
> + diversity mode (1 master, 1 slave). By default each
> + tuner is an individual master.
> +- maxim,refout-load: load capacitance value (in pF) on reference output
> + drive level. The mapping of these load values to
> + respective bit values are given below.
> + 0 - Reference output disabled
> + 1 - 10pF load
> + 2 - 20pF load
> + 3 - 30pF load
> + 4 - 40pF load
> + 5 - 60pF load
> + 6 - 70pF load
For properties involving units, usually the unit is made part of the
property name, e.g. maxim,refout-load-pF = 40.
This avoids confusion, and allows for extension later.
> +/* A tuner device instance under i2c bus */
> +max2175_0: tuner@60 {
> + #clock-cells = <0>;
> + compatible = "maxim,max2175";
> + reg = <0x60>;
> + clocks = <&maxim_xtal>;
> + clock-names = "xtal";
> + maxim,refout-load = <10>;
10 is not listed above. Perhaps you meant 10 pF?
> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.c
> @@ -0,0 +1,1624 @@
> +/* NOTE: Any addition/deletion in the below list should be reflected in
> + * max2175_modetag enum
> + */
You can drop the above comment if you make this explicit using C99
designated initializers, cfr. below.
> +static const struct max2175_rxmode eu_rx_modes[] = { /* Indexed by EU modetag */
> + /* EU modes */
> + { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },
[MAX2175_DAB_1_2] = { MAX2175_BAND_VHF, 182640000, 0, { 0, 0, 0, 0 } },
> +};
> +
> +static const struct max2175_rxmode na_rx_modes[] = { /* Indexed by NA modetag */
> + /* NA modes */
> + { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },
[MAX2175_NA_FM_1_0] = { MAX2175_BAND_FM, 98255520, 1, { 0, 0, 0, 0 } },
> +struct max2175_ctx {
> + struct v4l2_subdev sd;
> + struct i2c_client *client;
> + struct device *dev;
> +
> + /* Cached configuration */
> + u8 regs[256];
> + enum max2175_modetag mode; /* Receive mode tag */
> + u32 freq; /* In Hz */
> + struct max2175_rxmode *rx_modes;
> +
> + /* Device settings */
> + bool master;
> + u32 decim_ratio;
> + u64 xtal_freq;
> +
> + /* ROM values */
> + u8 rom_bbf_bw_am;
> + u8 rom_bbf_bw_fm;
> + u8 rom_bbf_bw_dab;
> +
> + /* Local copy of old settings */
> + u8 i2s_test;
> +
> + u8 nbd_gain;
> + u8 nbd_threshold;
> + u8 wbd_gain;
> + u8 wbd_threshold;
> + u8 bbd_threshold;
> + u8 bbdclip_threshold;
> + u8 lt_wbd_threshold;
> + u8 lt_wbd_gain;
> +
> + /* Controls */
> + struct v4l2_ctrl_handler ctrl_hdl;
> + struct v4l2_ctrl *lna_gain; /* LNA gain value */
> + struct v4l2_ctrl *if_gain; /* I/F gain value */
> + struct v4l2_ctrl *pll_lock; /* PLL lock */
> + struct v4l2_ctrl *i2s_en; /* I2S output enable */
> + struct v4l2_ctrl *i2s_mode; /* I2S mode value */
> + struct v4l2_ctrl *am_hiz; /* AM High impledance input */
> + struct v4l2_ctrl *hsls; /* High-side/Low-side polarity */
> + struct v4l2_ctrl *rx_mode; /* Receive mode */
> +
> + /* Driver private variables */
> + bool mode_resolved; /* Flag to sanity check settings */
> +};
Sorting the struct members by decreasing size helps to avoid gaps due to
alignment restrictions, and may reduce memory consumption.
> +/* Flush local copy to device from idx to idx+len (inclusive) */
> +static void max2175_flush_regstore(struct max2175_ctx *ctx, u8 idx, u8 len)
> +{
> + u8 i;
I'd just use unsigned int for loop counters.
> +
> + for (i = idx; i <= len; i++)
> + max2175_reg_write(ctx, i, ctx->regs[i]);
> +}
> +static int max2175_update_i2s_mode(struct max2175_ctx *ctx, u32 i2s_mode)
> +{
> + /* Only change if it's new */
> + if (max2175_read_bits(ctx, 29, 2, 0) == i2s_mode)
Many magic numbers, not only here (29, 2), but everywhere.
Can you please add #defines for these?
> + return 0;
> +
> + max2175_write_bits(ctx, 29, 2, 0, i2s_mode);
> +
> + /* Based on I2S mode value I2S_WORD_CNT values change */
> + if (i2s_mode == MAX2175_I2S_MODE3) {
> + max2175_write_bits(ctx, 30, 6, 0, 1);
> + } else if (i2s_mode == MAX2175_I2S_MODE2 ||
> + i2s_mode == MAX2175_I2S_MODE4) {
> + max2175_write_bits(ctx, 30, 6, 0, 0);
> + } else if (i2s_mode == MAX2175_I2S_MODE0) {
> + max2175_write_bits(ctx, 30, 6, 0,
> + ctx->rx_modes[ctx->mode].i2s_word_size);
> + } else {
> + v4l2_err(ctx->client,
> + "failed: i2s_mode %u unsupported\n", i2s_mode);
> + return 1;
> + }
switch (i2s_mode) { ... }
> + mxm_dbg(ctx, "updated i2s_mode %u\n", i2s_mode);
> + return 0;
> +}
> +static void max2175_set_filter_coeffs(struct max2175_ctx *ctx, u8 m_sel,
> + u8 bank, const u16 *coeffs)
> +{
> + u8 i, coeff_addr, upper_address;
I'd just use unsigned int for these.
> +
> + mxm_dbg(ctx, "start: m_sel %d bank %d\n", m_sel, bank);
> + max2175_write_bits(ctx, 114, 5, 4, m_sel);
> +
> + if (m_sel == 2)
> + upper_address = 12;
> + else
> + upper_address = 24;
> +
> + max2175_set_bit(ctx, 117, 7, 1);
> + for (i = 0; i < upper_address; i++) {
> + coeff_addr = i + (bank * 24);
> + max2175_set_bits(ctx, 115, 7, 0,
> + (u8)((coeffs[i] >> 8) & 0xff));
> + max2175_set_bits(ctx, 116, 7, 0, (u8)(coeffs[i] & 0xff));
I don't think you need the casts to u8, or the masking with 0xff.
> + max2175_set_bits(ctx, 117, 6, 0, coeff_addr);
> + max2175_flush_regstore(ctx, 115, 3);
> + }
> + max2175_write_bit(ctx, 117, 7, 0);
> +}
> +
> +static void max2175_load_dab_1p2(struct max2175_ctx *ctx)
> +{
> + u32 i;
unsigned int?
> +static int max2175_set_lo_freq(struct max2175_ctx *ctx, u64 lo_freq)
> +{
> + int ret;
> + u32 lo_mult;
> + u64 scaled_lo_freq;
> + const u64 scale_factor = 1000000ULL;
> + u64 scaled_npf, scaled_integer, scaled_fraction;
> + u32 frac_desired, int_desired;
> + u8 loband_bits, vcodiv_bits;
> +
> + scaled_lo_freq = lo_freq;
> + /* Scale to larger number for precision */
> + scaled_lo_freq = scaled_lo_freq * scale_factor * 100;
> +
> + mxm_dbg(ctx, "scaled lo_freq %llu lo_freq %llu\n",
> + scaled_lo_freq, lo_freq);
> +
> + if (MAX2175_IS_BAND_AM(ctx)) {
> + if (max2175_get_bit(ctx, 5, 7) == 0)
> + loband_bits = 0;
> + vcodiv_bits = 0;
> + lo_mult = 16;
> + } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_FM) {
> + if (lo_freq <= 74700000) {
> + loband_bits = 0;
> + vcodiv_bits = 0;
> + lo_mult = 16;
> + } else if ((lo_freq > 74700000) && (lo_freq <= 110000000)) {
> + loband_bits = 1;
> + vcodiv_bits = 0;
> + } else {
> + loband_bits = 1;
> + vcodiv_bits = 3;
> + }
> + lo_mult = 8;
> + } else if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_VHF) {
> + if (lo_freq <= 210000000) {
> + loband_bits = 2;
> + vcodiv_bits = 2;
> + } else {
> + loband_bits = 2;
> + vcodiv_bits = 1;
> + }
> + lo_mult = 4;
> + } else {
> + loband_bits = 3;
> + vcodiv_bits = 2;
> + lo_mult = 2;
> + }
> +
> + if (max2175_get_bits(ctx, 5, 1, 0) == MAX2175_BAND_L)
> + scaled_npf = (scaled_lo_freq / ctx->xtal_freq / lo_mult) / 100;
> + else
> + scaled_npf = (scaled_lo_freq / ctx->xtal_freq * lo_mult) / 100;
Please use one of the div64*() functions for divisions involving 64-bit
quantities (try to build for 32-bit and see). More of these below...
> + scaled_integer = scaled_npf / scale_factor * scale_factor;
> + int_desired = (u32)(scaled_npf / scale_factor);
> + scaled_fraction = scaled_npf - scaled_integer;
> + frac_desired = (u32)(scaled_fraction * 1048576 / scale_factor);
> + /* Write the calculated values to the appropriate registers */
> + max2175_set_bits(ctx, 5, 3, 2, loband_bits);
> + max2175_set_bits(ctx, 6, 7, 6, vcodiv_bits);
> + max2175_set_bits(ctx, 1, 7, 0, (u8)(int_desired & 0xff));
> + max2175_set_bits(ctx, 2, 3, 0, (u8)((frac_desired >> 16) & 0x1f));
> + max2175_set_bits(ctx, 3, 7, 0, (u8)((frac_desired >> 8) & 0xff));
> + max2175_set_bits(ctx, 4, 7, 0, (u8)(frac_desired & 0xff));
No need for casts etc.
> + /* Flush the above registers to device */
> + max2175_flush_regstore(ctx, 1, 6);
> + return ret;
> +}
> +
> +static int max2175_set_nco_freq(struct max2175_ctx *ctx, s64 nco_freq_desired)
> +{
> + int ret;
> + u64 clock_rate, abs_nco_freq;
> + s64 nco_freq, nco_val_desired;
> + u32 nco_reg;
> + const u64 scale_factor = 1000000ULL;
> +
> + mxm_dbg(ctx, "nco_freq: freq = %lld\n", nco_freq_desired);
> + clock_rate = ctx->xtal_freq / ctx->decim_ratio;
> + nco_freq = -nco_freq_desired;
> +
> + if (nco_freq < 0)
> + abs_nco_freq = -nco_freq;
> + else
> + abs_nco_freq = nco_freq;
> +
> + /* Scale up the values for precision */
> + if (abs_nco_freq < (clock_rate / 2)) {
> + nco_val_desired = (2 * nco_freq * scale_factor) / clock_rate;
> + } else {
> + if (nco_freq < 0)
> + nco_val_desired = (-2 * (clock_rate - abs_nco_freq) *
> + scale_factor) / clock_rate;
> + else
> + nco_val_desired = (2 * (clock_rate - abs_nco_freq) *
> + scale_factor) / clock_rate;
> + }
> +
> + /* Scale down to get the fraction */
> + if (nco_freq < 0)
> + nco_reg = 0x200000 + ((nco_val_desired * 1048576) /
> + scale_factor);
> + else
> + nco_reg = (nco_val_desired * 1048576) / scale_factor;
More 64-bit divisions. In addition, the dividers are 64-bit too.
Can't they be 32-bit?
> +static int max2175_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct max2175_ctx *ctx;
> + struct device *dev = &client->dev;
> + struct v4l2_subdev *sd;
> + struct v4l2_ctrl_handler *hdl;
> + struct clk *clk;
> + bool master = true;
> + u32 refout_load, refout_bits = 0; /* REFOUT disabled */
> + int ret;
> +
> + /* Check if the adapter supports the needed features */
> + if (!i2c_check_functionality(client->adapter,
> + I2C_FUNC_SMBUS_BYTE_DATA)) {
> + dev_err(&client->dev, "i2c check failed\n");
> + return -EIO;
> + }
> +
> + if (of_find_property(client->dev.of_node, "maxim,slave", NULL))
> + master = false;
> +
> + if (!of_property_read_u32(client->dev.of_node, "maxim,refout-load",
> + &refout_load))
> + refout_bits = max2175_refout_load_to_bits(client, refout_load);
> +
> + clk = devm_clk_get(&client->dev, "xtal");
> + if (IS_ERR(clk)) {
> + ret = PTR_ERR(clk);
> + dev_err(&client->dev, "cannot get xtal clock %d\n", ret);
> + return -ENODEV;
> + }
> +
> + ctx = kzalloc(sizeof(struct max2175_ctx),
> + GFP_KERNEL);
devm_kzalloc()?
> + if (ctx == NULL)
> + return -ENOMEM;
> +
> + sd = &ctx->sd;
> + ctx->master = master;
> + ctx->mode_resolved = false;
> +
> + /* Set the defaults */
> + ctx->freq = bands_rf.rangelow;
> +
> + ctx->xtal_freq = clk_get_rate(clk);
> + dev_info(&client->dev, "xtal freq %lluHz\n", ctx->xtal_freq);
> +
> + v4l2_i2c_subdev_init(sd, client, &max2175_ops);
> + ctx->client = client;
> +
> + sd->flags = V4L2_SUBDEV_FL_HAS_DEVNODE;
> + ctx->dev = dev;
> +
> + /* Controls */
> + hdl = &ctx->ctrl_hdl;
> + ret = v4l2_ctrl_handler_init(hdl, 8);
> + if (ret) {
> + dev_err(&client->dev, "ctrl handler init failed\n");
> + goto err;
> + }
> +
> + ctx->lna_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> + V4L2_CID_RF_TUNER_LNA_GAIN,
> + 0, 15, 1, 2);
> + ctx->lna_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> + V4L2_CTRL_FLAG_READ_ONLY);
> + ctx->if_gain = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> + V4L2_CID_RF_TUNER_IF_GAIN,
> + 0, 31, 1, 0);
> + ctx->if_gain->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> + V4L2_CTRL_FLAG_READ_ONLY);
> + ctx->pll_lock = v4l2_ctrl_new_std(hdl, &max2175_ctrl_ops,
> + V4L2_CID_RF_TUNER_PLL_LOCK,
> + 0, 1, 1, 0);
> + ctx->pll_lock->flags |= (V4L2_CTRL_FLAG_VOLATILE |
> + V4L2_CTRL_FLAG_READ_ONLY);
> + ctx->i2s_en = v4l2_ctrl_new_custom(hdl, &max2175_i2s_en, NULL);
> + ctx->i2s_mode = v4l2_ctrl_new_custom(hdl, &max2175_i2s_mode, NULL);
> + ctx->am_hiz = v4l2_ctrl_new_custom(hdl, &max2175_am_hiz, NULL);
> + ctx->hsls = v4l2_ctrl_new_custom(hdl, &max2175_hsls, NULL);
> +
> + if (ctx->xtal_freq == MAX2175_EU_XTAL_FREQ) {
> + ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> + &max2175_eu_rx_mode, NULL);
> + ctx->rx_modes = (struct max2175_rxmode *)eu_rx_modes;
> + } else {
> + ctx->rx_mode = v4l2_ctrl_new_custom(hdl,
> + &max2175_na_rx_mode, NULL);
> + ctx->rx_modes = (struct max2175_rxmode *)na_rx_modes;
> + }
The casts are meant to cast away constness. Can that be avoided?
> --- /dev/null
> +++ b/drivers/media/i2c/max2175/max2175.h
> +/* NOTE: Any addition/deletion in the below enum should be reflected in
> + * V4L2_CID_MAX2175_RX_MODE ctrl strings
Which strings exactly?
> + */
> +enum max2175_modetag {
> + /* EU modes */
> + MAX2175_DAB_1_2 = 0,
> +
> + /* Other possible modes to add in future
> + * MAX2175_DAB_1_0,
> + * MAX2175_DAB_1_3,
> + * MAX2175_EU_FM_2_2,
> + * MAX2175_EU_FM_1_0,
> + * MAX2175_EU_FMHD_4_0,
> + * MAX2175_EU_AM_1_0,
> + * MAX2175_EU_AM_2_2,
> + */
> +
> + /* NA modes */
> + MAX2175_NA_FM_1_0 = 0,
> +
> + /* Other possible modes to add in future
> + * MAX2175_NA_FM_1_2,
> + * MAX2175_NA_FMHD_1_0,
> + * MAX2175_NA_FMHD_1_2,
> + * MAX2175_NA_AM_1_0,
> + * MAX2175_NA_AM_1_2,
> + */
The MAX2175_NA_* definitions share their values with the MAX2175_DAB_* and
future MAX2175_EU_* values. Do you have to use a single enum for both?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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